I bought a "dead" 1551 drive a few months ago. It's a european model, only 220v, and they said "it smoked when it was on". Well, i figured it was dead but I figured maybe not dead dead.
So, step one was removing the .. huge ass transformer.
I stripped off the regulators and hooked it up to a pair of bench supplies to feed 5v and 12v with a current limit.
(And yes, by this stage I had done a bunch of debugging already, so i had taken out the ROM, PLA and RAM and socketed the PLA / RAM.)
I unplugged the drive head cable and measured it - the heads measured just fine. So, I left them off whilst I debugged everything else.
Then I fired it up - the drive spun, a bunch of CPU pins were blinking on the oscilloscope, but nothing quite worked. The drive constantly spinning is a sign that even the early boot code isn't running.
So I then wanted to know if the CPU worked. The problem? All the pins kinda looked fine. Except A15.
It looked very sus. Like ok, NMOS has some fun rise times, but the other pins weren't this fun.
I decided to socket everything so I could pull the RAM and address decode gate array out. I thought about the 42 pin drive gate array IC but I figured if that was fried I was in for an unfun time.
The next thing was to figure out how to test that the CPU kinda worked. I figured I could write a little program to toggle the activity LED quickly and see it on my scope. I started with the disassembly here - http://www.cbmhardware.de/show.php?r=7&id=21 - to see how the LED is blinked. The 6510T CPU has an 8 bit IO port (versus the 6 bit IO port on the 6510 CPU).
The program looked roughly like this:
.org $ff00 SEI ; disable interrupts CLD ; clear flags LDA #$6F ; IO direction bits STA $00 ; program IO direction bits loop: LDA #$60 ; turn on LED STA $01 ; program IO port LDA #$68 ; turn off LED STA $01 ; program IO port JMP loop
.org $fffa .byte $00, $ff, $00, $ff, $00, $ff
This didn't work. So, I got a new CPU. A15 on that CPU was much better.
Then this did work. The LED was blinking at a few hundred kilohertz. Ok, but the original ROM? Nothing. My guess is the ROM is also busted, so I programmed another 27128 EPROM with the right image and inserted it into the drive.
Everything worked! So, time to plug in the head cable OH CRAP I PLUGGED IT IN BACKWARDS. Bang, I blew the head coils. Crap.
Anyway, the rest of the drive seemed fine. Stepper motor, drive motor control. Now, the challenge - it's a mitsumi drive. I went on ebay to find a replacement drive - lots of "untested" 1541's everywhere. But I did find a "tested, guaranteed works" SX-64 drive. However, it's an Alps drive. They're supposed to be more reliable, but .. well, it arrived a few days later.
The main physical difference between the two is the connector. The thing I remember is that the write current is slightly different and some 1541 drives have a jumper to change said current.
Luckily there's a 1541 service manual and it has the Alps drive pinout for the 1541, which is surprisingly exactly what I need for the 1551:
So I followed this guide, verified at each step that it worked, and connected it all up.
And yes, I put superglue in the key hole for the head connector so I didn't plug it in backwards.
And .. well, it works!
Well, kinda. I had the commodore 16 drop into the monitor after HEADER (which formats a blank disk) completed. I've also had some issues with commands hanging and not running on the drive. So, there may be some other issues lurking.
I also want to figure out a suitable mod for the write head current change.
But hey, I guess I do have a working Alps drive in my 1551.
And yes I did tear the head apart to see how it's put together... :-)
A SWAY session by Joanne of Royal Far West School. http://sway.org.au/ via https://coviu.com/ SWAY is an oral language and literacy program based on Aboriginal knowledge, culture and stories. It has been developed by Educators, Aboriginal Education Officers and Speech Pathologists at the Royal Far West School in Manly, NSW.
The XKCD comic Code Quality [1] inspired me to test out emoji in source. I really should have done this years ago when that XKCD was first published.
The following code compiles in gcc and runs in the way that anyone who wants to write such code would want it to run. The hover text in the XKCD comic is correct. You could have a style guide for such programming, store error messages in the doctor and nurse emoji for example.
#include <stdio.h>
int main()
{
int 😇 = 1, 😈 = 2;
printf("😇=%d, 😈=%d\n", 😇, 😈);
return 0;
}
To get this to display correctly in Debian you need to install the fonts-noto-color-emoji package (used by the KDE emoji picker that runs when you press Windows-. among other things) and restart programs that use emoji. The Konsole terminal emulator will probably need it’s profile settings changed to work with this if you ran Konsole before installing fonts-noto-color-emoji. The Kitty terminal emulator works if you restart it after installing fonts-noto-color-emoji.
This web page gives a list of HTML codes for emoji [2]. If I start writing real code with emoji variable names then I’ll have to update my source to HTML conversion script (which handles <>" and repeated spaces) to convert emoji.
I spent a couple of hours on this and I think it’s worth it. I have filed several Debian bug reports about improvements needed to issues related to emoji.
To resolve that you could upgrade to SE Linux, but the other option is to create a file named /etc/apparmor.d/bwrap with the following contents:
abi <abi/4.0>,
include <tunables/global>
profile bwrap /usr/bin/bwrap flags=(unconfined) {
userns,
# Site-specific additions and overrides. See local/README for details.
include if exists <local/bwrap>
}
The PinePhone keyboard contains a battery, which will be used to charge the PinePhone when the keyboard is attached. Althrough there are existing warnings on the pine64 wiki which sums up to ‘don’t charge or connect anything to your pinephone’s type C interface when the keyboard is attached’, my two pinephone keyboards still managed to fry themselves, with one releasing stinky magic smoke and the other melting the plastic around the pogo pins on the pinephone backplate.
This all happened while the pinephone’s type C interface being physically block when attached to the keyboard. In the first case, the keyboard’s controller PCB blew up when I tried to charge it, in the latter case the keyboard somehow overheated and melted the plastic near the pogo interface on the phone side.
Pine64 provided me a free replacement keyboard after multiple emails back and forth, but according to Pine64 there will be no more free replacement for me in future, and there is no guarantee that this will not happen to my replacement keyboard.
The cost for replacing all the fried parts with spare parts from the Pine64 store is about 40 USD (pogo pins + backplate + keyboard PCB), and considering this problem is likely to happen again, I don’t think purchasing those parts is a wise decision.
Both the melting plastic and the magic smoke originated from the fact that charges are constantly shuffled around when the keyboard is attached to the pinephone, and since the keyboard can function independently from the battery, we can disconnect and remove the battery from the keyboard case to make sure it will not blow up again. After such precedure the keyboard will keep functioning althrough the keyboard-attached pinephone might flip over much more easily due to the lightened keyboard base. Be aware that the keyboard isn’t designed to be taken apart, and doing so will likely result in scratches on the case. As for me, I’d much rather have a keyboard case without builtin battery than have something that can overheat or blow up.
So I read this paper over the weekend. Naively, its a resonably interesting piece of research around using a generative AI to use descriptions of CVEs from their responsible disclosures to exploit unpatched systems autonomously. Now read that sentence again — these people prompted Chat GPT4 with CVES which didn’t have fixes yet, and had it hacking unpatched systems with an 85% success rate.
In New python syntax I was previously unaware of, I discussed some new operators I’d recently discovered. One of them is called the Walrus operator, which lets you write code like this:
list = ['a', 'b', 'c']
def get_one():
if not list:
return None
return list.pop()
while one := get_one():
print(one)
See where we do the assignment inside the while? That code returns:
c
b
a
Which is as expected. However, the Walrus operator is strict about needing a None returned to end the iteration. I had code which was more like this:
list = [('a', 1), ('b', 2), ('c', 3)]
def get_one():
if not list:
return None, None
return list.pop()
while one := get_one():
print(one)
And the while loop never terminates. It just prints (None, None) over and over. So there you go.
Developing in the open, building a product with our users by Toby Bellwood
The Lagoon Story
At amazee.io . Is Lagoon Lead
What is Lagoon
Application to Kubernetes (docker build for customer, converts to k8s)
Docker based
Based on git workflows. Mostly Drupal, WordPress, PHP and NodeJS apps
Presets for the extra stuff like monitoring etc
Why
Cause Developers are too busy to do all that extra stuff
and it means Ops prefer if it was all automated away (the right way)
8 full-time team members
Knows a lot about application, not so much about the users (apart from Amazee.io)
Users: Hosting providers, Agencies, Developers
The Adopter: Someone using it for something else, weird use cases
Agencies: Need things to go out quickly, want automation, like documentation to be good. Often will need weird technologies cause customers wants that.
Developers: Just want it stabele. Only worried about one project at at time. Often OS minded
User Mindset
Building own tools using application
Do walking tours of the system, recorded zoom session
Use developer tools
Discord, Slack, Office Hours, Events, Easy Access to the team
Balance priorities
eg stuff customers will use even those Amazee won’t use
Engaging Upstream
Try to be a good participant, What they would want their customers to be
Encourage our teams to “contribute first”. Usually works well
Empowering the Team
Contribute under your own name
Participate in communities
How to stay Open Source forever?
Widening the Core Contributor Group
Learn from others in the Community. But most companies are not open sourcing the main component of their business.
Unsuccessful CNCF Sandbox project
Presenting n3n – A simple Peer to Peer VPN by Hamish Coleman
How to compares to other VPNs?
Peer to peer
NAT piecing
Not all packets need to go via the server
Distributed ethernet switch – gives extra features
Userspace except for tuntap driver which is pretty common
Low deployment requirements, easy to install in multiple environments
Relatively simple security, not super secure
History
Based off n2n (developed by the people who did ntop)
But they changed the license in October 2023
Decided to fork into a new project
First release of n3n in April 2024
Big change was they introduced a CLA (contributor licensing agreement)
CLAs have problems
Legal document
Needs real day, contributor hostile, asymmetry of power
Can lead to surprise relicencing
Alternatives to a CLA
Preserving Git history
Developer’s Certificate of Origin
Or it could be a CLA
Handling Changes
Don’t surprise your Volunteers
Don’t ignore your Volunteers
Do discuss with you Volunteers and bring them along
Alternatives
Wireguard – No NAT piercing
OpenVPN – Mostly client to Server. Also Too configurable
Why prefer
One simple access method (Speaker uses 4x OS)
A single access method
p2p avoid latency delays because local instances to talk directly
Goals
Protocol compatibility with n2n
Don’t break user visible APIs
Incrementally clean and improve codebase
How it works now
Supernode – Central co-ordination point, public IP, Some access control, Last-resort for packet forwarding
Communities – Nodes join, form a virtual segment
IP addresses
Can just run a DHCP server inside the network
Design
Tries to create a full mesh of nodes
Multiple Supernodes for metadata
Added a few features from n2n
INI file, Help text, Tidied up the CLI options and reduced options
Tried to make the defaults work better
Built in web server
Status page, jsonRPC, Socket interfaces, Monitoring/Stats
Current State of fork
Still young. Another contributor
Only soft announced. Growing base of awareness
Plans
IPv6
Optimise encryption/compression
Improve packaging and submit to distros
Test coverage
Better NAT piercing
Continue improve config experience
Selectable tuntap drivers
Mobile phone support hoped for but probably some distance away
Speaker’s uses for software
Manage mothers computer
Management interface for various servers around the world
From the stone age to silicon: The Dwarf Axe guide to the evolution of technology by Steven Ellis
What is a “Dwarf Axe” ?
Snowflakes vs Dwarf Axes
It’s an Axe that handled down and consistently delivers a service
Both the head ( software ) and the handle ( hardware ) are maintained and upgraded separately and must be maintained. Treated like the same platform even though it is quite different from what it was originally. Delivers the same services though
Keeps a fairly similar services. Same box on a organisation diagram
Home IT
Phones handed down to family members. Often not getting security patches anymore
Enterprise IT
Systems kept long past their expected lifetime
Maintained via virtualisation
What is wrong with a Big Axe?
Too Big to Fail
Billion dollar projects fail.
Alternatives
Virtual Machines – Running on Axe somewhere,
Containers – Something big to orchestrate the containers
Microservices – Also needs orchestration
Redesign the Axe
The cloud – It’s just someone else Axe
Options
Everything as a service. 3rd party services
Re-use has an end-of-life
Modern hardware should have better )and longer) hardware support
Ephemeral Abstraction
Run anywhere
Scale out not up
Avoid single points of failure
Focus on the service (not the infra or the platform)
When I first started studying computer science setting up a programming project was easy, write source code files and a Makefile and that was it. IRC was the only IM system and email was the only other communications system that was used much. Writing Makefiles is difficult but products like the Borland Turbo series of IDEs did all that for you so you could just start typing code and press a function key to compile and run (F5 from memory).
Over the years the requirements and expectations of computer use have grown significantly. The typical office worker is now doing many more things with computers than serious programmers used to do. Running an IM system, an online document editing system, and a series of web apps is standard for companies nowadays. Developers have to do all that in addition to tools for version control, continuous integration, bug reporting, and feature tracking. The development process is also more complex with extra steps for reproducible builds, automated tests, and code coverage metrics for the tests. I wonder how many programmers who started in the 90s would have done something else if faced with Github as their introduction.
How much of this is good? Having the ability to send instant messages all around the world is great. Having dozens of different ways of doing so is awful. When a company uses multiple IM systems such as MS-Teams and Slack and forces some of it’s employees to use them both it’s getting ridiculous. Having different friend groups on different IM systems is anti-social networking. In the EU the Digital Markets Act [1] forces some degree of interoperability between different IM systems and as it’s impossible to know who’s actually in the EU that will end up being world-wide.
In corporations document management often involves multiple ways of storing things, you have Google Docs, MS Office online, hosted Wikis like Confluence, and more. Large companies tend to use several such systems which means that people need to learn multiple systems to be able to work and they also need to know which systems are used by the various groups that they communicate with. Microsoft deserves some sort of award for the range of ways they have for managing documents, Sharepoint, OneDrive, Office Online, attachments to Teams rooms, and probably lots more.
During WW2 the predecessor to the CIA produced an excellent manual for simple sabotage [2]. If something like that was written today the section General Interference with Organisations and Production would surely have something about using as many incompatible programs and web sites as possible in the work flow. The proliferation of software required for work is a form of denial of service attack against corporations.
The efficiency of companies doesn’t really bother me. It sucks that companies are creating a demoralising workplace that is unpleasant for workers. But the upside is that the biggest companies are the ones doing the worst things and are also the most afflicted by these problems. It’s almost like the Bureau of Sabotage in some of Frank Herbert’s fiction [3].
The thing that concerns me is the effect of multiple standards on free software development. We have IRC the most traditional IM support system which is getting replaced by Matrix but we also have some projects using Telegram, and Jabber hasn’t gone away. I’m sure there are others too. There are also multiple options for version control (although github seems to dominate the market), forums, bug trackers, etc. Reporting bugs or getting support in free software often requires interacting with several of them. Developing free software usually involves dealing with the bug tracking and documentation systems of the distribution you use as well as the upstream developers of the software. If the problem you have is related to compatibility between two different pieces of free software then you can end up dealing with even more bug tracking systems.
There are real benefits to some of the newer programs to track bugs, write documentation, etc. There is also going to be a cost in changing which gives an incentive for the older projects to keep using what has worked well enough for them in the past,
How can we improve things? Use only the latest tools? Prioritise ease of use? Aim more for the entry level contributors?
One of the other architects at work was running a reading group for our North American comrades, and I felt left out so I figured I may as well just pick up the book to see what the deal was. This book is a bit old, and was written at the time to try and be funny, but to be honest I don’t think the humour has aged well and it makes the book jarring to read. Overall I’d describe the book as having been written in the style of a long form chatty blog post, which is a bit unusual.
90% of the readers of this book will be looking for advice on how to debug software systems, but the book frequently uses hardwaare systems as examples. That speaks to the author’s background, but its not super helpful for modern audiences living in a software defined world.
The book is also a bit dated in terms of terminology and expectations of the work environment — for example, the discussion of repeatable testing doesn’t mention automated regression testing at all, and the only mention of automated tests is fleeting at best. Another example is that the author recommends that you read the manual for whatever system you are testing from cover to cover before starting. Really? When was the last time you saw a real world system with a manual? Certainly for modern software systems this is basically unheard of. There might be a user guide, but engineering documentation is a step we seem to always skip these days.
The awkward bit is the nine rules are actually pretty good advice and have stood the test of time. They are:
Understand the system
Make it fail (stimulate the failure, but be careful not to simulate it)
Quit thinking and look (don’t guess at possible causes, go and seek evidence via instrumentation and direct measurement)
Divide and conquer
Change one thing at a time
Keep an audit trail
Check the plug
Get a fresh view
If you didn’t fix it, it ain’t fixed
I think in summary this book would have been a good blog post, but hasn’t aged well as an actual book. Sorry Dave, better luck next time.
Debugging
David J. Agans
Business & Economics
Amacom Books
September 30, 2006
183
Written in a frank but engaging style, this guide provides simple, foolproof principles guaranteed to help find any hardware or software bug quickly. It is applicable for any system in any circumstance.
Last year a Debian Developer blogged about writing Haskell code to give a bad result for LLMs that were trained on it. I forgot who wrote the post and I’d appreciate the URL if anyone has it.
I respect such technical work to enforce one’s legal rights when they aren’t respected by corporations, but I have a different approach.
For what I write I am at this time happy to allow it to be used as part of a large training data set (consider this blog post a licence grant that applies until such time as I edit this post to change it). But only if aggregated with so much other data that my content is only a tiny portion of the data set by any metric. So I don’t want someone to make a programming LLM that has my code as the only C code or a political data set that has my blog posts as the only left-wing content. If someone wants to train an LLM on only my content to make a Russell-simulator then I don’t license my work for that purpose but also as it’s small enough that anyone with a bit of skill could do it on a weekend I can’t stop it. I would be really interested in seeing the results if someone from the FOSS community wanted to make a Russell-simulator and would probably issue them a license for such work if asked.
If my work comprises more than 0.1% of the content in a particular measure (theme, programming language, political position, etc) in a training data set then I don’t permit that without prior discussion.
Finally if someone wants to make a FOSS training data set to be used for FOSS LLM systems (maybe under the AGPL or some similar license) then I’ll allow my writing to be used as part of that.
Those of you who haven’t been in IT for far, far too long might not know that next month will be the 16th(!) anniversary of the disclosure of what was, at the time, a fairly earth-shattering revelation: that for about 18 months, the Debian OpenSSL package was generating entirely predictable private keys.
The recent xz-stential threat (thanks to @nixCraft for making me aware of that one), has got me thinking about my own serendipitous interaction with a major vulnerability.
Given that the statute of limitations has (probably) run out, I thought I’d share it as a tale of how “huh, that’s weird” can be a powerful threat-hunting tool – but only if you’ve got the time to keep pulling at the thread.
Prelude to an Adventure
Our story begins back in March 2008.
I was working at Engine Yard (EY), a now largely-forgotten Rails-focused hosting company, which pioneered several advances in Rails application deployment.
Probably EY’s greatest claim to lasting fame is that they helped launch a little code hosting platform you might have heard of, by providing them free infrastructure when they were little more than a glimmer in the Internet’s eye.
I am, of course, talking about everyone’s favourite Microsoft product: GitHub.
Since GitHub was in the right place, at the right time, with a compelling product offering, they quickly started to gain traction, and grow their userbase.
With growth comes challenges, amongst them the one we’re focusing on today: SSH login times.
Then, as now, GitHub provided SSH access to the git repos they hosted, by SSHing to git@github.com with publickey authentication.
They were using the standard way that everyone manages SSH keys: the ~/.ssh/authorized_keys file, and that became a problem as the number of keys started to grow.
The way that SSH uses this file is that, when a user connects and asks for publickey authentication, SSH opens the ~/.ssh/authorized_keys file and scans all of the keys listed in it, looking for a key which matches the key that the user presented.
This linear search is normally not a huge problem, because nobody in their right mind puts more than a few keys in their ~/.ssh/authorized_keys, right?
Of course, as a popular, rapidly-growing service, GitHub was gaining users at a fair clip, to the point that the one big file that stored all the SSH keys was starting to visibly impact SSH login times.
This problem was also not going to get any better by itself.
Something Had To Be Done.
EY management was keen on making sure GitHub ran well, and so despite it not really being a hosting problem, they were willing to help fix this problem.
For some reason, the late, great, Ezra Zygmuntowitz pointed GitHub in my direction, and let me take the time to really get into the problem with the GitHub team.
After examining a variety of different possible solutions, we came to the conclusion that the least-worst option was to patch OpenSSH to lookup keys in a MySQL database, indexed on the key fingerprint.
We didn’t take this decision on a whim – it wasn’t a case of “yeah, sure, let’s just hack around with OpenSSH, what could possibly go wrong?”.
We knew it was potentially catastrophic if things went sideways, so you can imagine how much worse the other options available were.
Ensuring that this wouldn’t compromise security was a lot of the effort that went into the change.
In the end, though, we rolled it out in early April, and lo! SSH logins were fast, and we were pretty sure we wouldn’t have to worry about this problem for a long time to come.
Normally, you’d think “patching OpenSSH to make mass SSH logins super fast” would be a good story on its own.
But no, this is just the opening scene.
Chekov’s Gun Makes its Appearance
Fast forward a little under a month, to the first few days of May 2008.
I get a message from one of the GitHub team, saying that somehow users were able to access other users’ repos over SSH.
Naturally, as we’d recently rolled out the OpenSSH patch, which touched this very thing, the code I’d written was suspect number one, so I was called in to help.
They're called The Usual Suspects for a reason, but sometimes, it really is Keyser Söze
Eventually, after more than a little debugging, we discovered that, somehow, there were two users with keys that had the same key fingerprint.
This absolutely shouldn’t happen – it’s a bit like winning the lottery twice in a row1 – unless the users had somehow shared their keys with each other, of course.
Still, it was worth investigating, just in case it was a web application bug, so the GitHub team reached out to the users impacted, to try and figure out what was going on.
The users professed no knowledge of each other, neither admitted to publicising their key, and couldn’t offer any explanation as to how the other person could possibly have gotten their key.
Then things went from “weird” to “what the…?”.
Because another pair of users showed up, sharing a key fingerprint – but it was a different shared key fingerprint.
The odds now have gone from “winning the lottery multiple times in a row” to as close to “this literally cannot happen” as makes no difference.
Once we were really, really confident that the OpenSSH patch wasn’t the cause of the problem, my involvement in the problem basically ended.
I wasn’t a GitHub employee, and EY had plenty of other customers who needed my help, so I wasn’t able to stay deeply involved in the on-going investigation of The Mystery of the Duplicate Keys.
However, the GitHub team did keep talking to the users involved, and managed to determine the only apparent common factor was that all the users claimed to be using Debian or Ubuntu systems, which was where their SSH keys would have been generated.
That was as far as the investigation had really gotten, when along came May 13, 2008.
Chekov’s Gun Goes Off
With the publication of DSA-1571-1, everything suddenly became clear.
Through a well-meaning but ultimately disasterous cleanup of OpenSSL’s randomness generation code, the Debian maintainer had inadvertently reduced the number of possible keys that could be generated by a given user from “bazillions” to a little over 32,000.
With so many people signing up to GitHub – some of them no doubt following best practice and freshly generating a separate key – it’s unsurprising that some collisions occurred.
You can imagine the sense of “oooooooh, so that’s what’s going on!” that rippled out once the issue was understood.
I was mostly glad that we had conclusive evidence that my OpenSSH patch wasn’t at fault, little knowing how much more contact I was to have with Debian weak keys in the future, running a huge store of known-compromised keys and using them to find misbehaving Certificate Authorities, amongst other things.
Lessons Learned
While I’ve not found a description of exactly when and how Luciano Bello discovered the vulnerability that became CVE-2008-0166, I presume he first came across it some time before it was disclosed – likely before GitHub tripped over it.
The stable Debian release that included the vulnerable code had been released a year earlier, so there was plenty of time for Luciano to have discovered key collisions and go “hmm, I wonder what’s going on here?”, then keep digging until the solution presented itself.
The thought “hmm, that’s odd”, followed by intense investigation, leading to the discovery of a major flaw is also what ultimately brought down the recent XZ backdoor.
The critical part of that sequence is the ability to do that intense investigation, though.
When I reflect on my brush with the Debian weak keys vulnerability, what sticks out to me is the fact that I didn’t do the deep investigation.
I wonder if Luciano hadn’t found it, how long it might have been before it was found.
The GitHub team would have continued investigating, presumably, and perhaps they (or I) would have eventually dug deep enough to find it.
But we were all super busy – myself, working support tickets at EY, and GitHub feverishly building features and fighting the fires in their rapidly-growing service.
As it was, Luciano was able to take the time to dig in and find out what was happening, but just like the XZ backdoor, I feel like we, as an industry, got a bit lucky that someone with the skills, time, and energy was on hand at the right time to make a huge difference.
It’s a luxury to be able to take the time to really dig into a problem, and it’s a luxury that most of us rarely have.
Perhaps an understated takeaway is that somehow we all need to wrestle back some time to follow our hunches and really dig into the things that make us go “hmm…”.
the odds are actually probably more like winning the lottery about twenty times in a row.
The numbers involved are staggeringly huge, so it’s easiest to just approximate it as “really, really unlikely”. ↩
Covers the career of the makers (ZAZ) and the long path to writing, pitching, pre-production and making of the classic movie. As well as reactions to it. 4/5
Following a cold case Maigret gatecrashes the weekend gathering of a group of friends when one is unexpectedly murdered. Felt a little unrealistic at times. 3/5
OpenBSD supported riscv64 since the 7.0 release, but officially supported hardwares are still not easy to obtain. To have some fun with OpenBSD/riscv64 without access to such hardware, and to potentially bring up other hardware platforms by extending kernel supports, we can run a Qemu virtual machine on a common x86 system. What’s documented here is done on a X86_64 Debian host, but any system with sufficiently new Qemu available should work.
I have been paid money to write Python code since about 2006, so I figured it was probably time that I should understand some of the inner workings of Python. I therefore picked up two books on the topic, this one being the first of the two.
This book to be honest isn’t completely what I expected. Its very well written and quite interesting, but its more about the things you’d need to know to become a Python core developer, rather than the things you should know as a user of Python like how the Python dictionary implementation is built.
(If you want that specifically, this video is an excellent introduction).
The book starts with the assumption that you are going to want to customize Python and recompile it (which while educational is probably a truly terrible idea in the real world), so the first couple of chapters are devoted to setting up a development and compilation environment for Python on various platforms, which seems fair enough to me. The book then moves into a discussion of how the language grammar is defined and parsed, which is something I haven’t really thought about since my compilers course at university.
Interestingly, within the first couple of chapters of the book I had learnt about Python syntax constructs I was unaware of as someone who struggles a bit to keep you with the development of the language over time. So even that aspect has been quite useful. I’ll document some examples of new syntax I learnt in another blog post so as to keep this post about the book itself.
The book then moves on to describing at a high level how the Python bytecode runtime works. It then describes memory allocation. Next is multiprocessing including the exact mechanism that Python uses to fork a new process or thread — punch line, its more complicated than it would look if your mental model is how fork works in C. These topics are all dealt with in detail, which is likely helpful to total computer science newbies, but is sometimes a bit excruciating if you already know what a semaphore is.
The coverage of misuses of yield, coroutines, and async is quite good I think. Sub interpreters sound interesting too, although too experimental for use quite yet. There is extensive coverage of the various Python data types, including how the Python number type is slightly bonkers and how unicode works under the hood. There is in fact even some coverage of how dictionaries work, but the video above is better to be honest.
Overall I enjoyed this book and I definitely learned things. I wouldn’t recommend it to a Python newbie, but if you’re an experienced developer and want to understand of what life is like under the hood then this is a good place to start.
CPython Internals
Anthony Shaw
May 5, 2021
396
Get your guided tour through the Python 3.9 interpreter: Unlock the inner workings of the Python language, compile the Python interpreter from source code, and participate in the development of CPython. Are there certain parts of Python that just seem like magic? This book explains the concepts, ideas, and technicalities of the Python interpreter in an approachable and hands-on fashion. Once you see how Python works at the interpreter level, you can optimize your applications and fully leverage the power of Python.
There have been many experiments with the sizes of computers, some of which have stayed around and some have gone away. The trend has been to make computers smaller, the early computers had buildings for them. Recently for come classes computers have started becoming as small as could be reasonably desired. For example phones are thin enough that they can blow away in a strong breeze, smart watches are much the same size as the old fashioned watches they replace, and NUC type computers are as small as they need to be given the size of monitors etc that they connect to.
This means that further development in the size and shape of computers will largely be determined by human factors.
I think we need to consider how computers might be developed to better suit humans and how to write free software to make such computers usable without being constrained by corporate interests.
Those of us who are involved in developing OSs and applications need to consider how to adjust to the changes and ideally anticipate changes. While we can’t anticipate the details of future devices we can easily predict general trends such as being smaller, higher resolution, etc.
Desktop/Laptop PCs
When home computers first came out it was standard to have the keyboard in the main box, the Apple ][ being the most well known example. This has lost popularity due to the demand to have multiple options for a light keyboard that can be moved for convenience combined with multiple options for the box part. But it still pops up occasionally such as the Raspberry Pi 400 [1] which succeeds due to having the computer part being small and light. I think this type of computer will remain a niche product. It could be used in a “add a screen to make a laptop” as opposed to the “add a keyboard to a tablet to make a laptop” model – but a tablet without a keyboard is more useful than a non-server PC without a display.
The PC as “box with connections for keyboard, display, etc” has a long future ahead of it. But the sizes will probably decrease (they should have stopped making PC cases to fit CD/DVD drives at least 10 years ago). The NUC size is a useful option and I think that DVD drives will stop being used for software soon which will allow a range of smaller form factors.
The Lenovo Thinkpad X1 Fold [3] and related Lenovo products are very interesting. Advances in materials allow laptops to be thinner and lighter which leaves the screen size as a major limitation to portability. There is a conflict between desiring a large screen to see lots of content and wanting a small size to carry and making a device foldable is an obvious solution that has recently become possible. Making a foldable laptop drives a desire for not having a permanently attached keyboard which then makes a touch screen keyboard a requirement. So this means that user interfaces for PCs have to be adapted to work well on touch screens. The Think line seems to be continuing the history of innovation that it had when owned by IBM. There are also a range of other laptops that have two regular screens so they are essentially the same as the Thinkpad X1 Fold but with two separate screens instead of one folding one, prices are as low as $600US.
I think that the typical interfaces for desktop PCs (EG MS-Windows and KDE) don’t work well for small devices and touch devices and the Android interface generally isn’t a good match for desktop systems. We need to invent more options for this. This is not a criticism of KDE, I use it every day and it works well. But it’s designed for use cases that don’t match new hardware that is on sale. As an aside it would be nice if Lenovo gave samples of their newest gear to people who make significant contributions to GUIs. Give a few Thinkpad Fold devices to KDE people, a few to GNOME people, and a few others to people involved in Wayland development and see how that promotes software development and future sales.
We also need to adopt features from laptops and phones into desktop PCs. When voice recognition software was first released in the 90s it was for desktop PCs, it didn’t take off largely because it wasn’t very accurate (none of them recognised my voice). Now voice recognition in phones is very accurate and it’s very common for desktop PCs to have a webcam or headset with a microphone so it’s time for this to be re-visited. GPS support in laptops is obviously useful and can work via Wifi location, via a USB GPS device, or via wwan mobile phone hardware (even if not used for wwan networking). Another possibility is using the same software interfaces as used for GPS on laptops for a static definition of location for a desktop PC or server.
The Interesting New Things
Watch Like
The wrist-watch [4] has been a standard format for easy access to data when on the go since it’s military use at the end of the 19th century when the practical benefits beat the supposed femininity of the watch. So it seems most likely that they will continue to be in widespread use in computerised form for the forseeable future. For comparison smart phones have been in widespread use as “pocket watches” for about 10 years.
The question is how will watch computers end up? Will we have Dick Tracy style watch phones that you speak into? Will it be the current smart watch functionality of using the watch to answer a call which goes to a bluetooth headset? Will smart watches end up taking over the functionality of the calculator watch [5] which was popular in the 80’s? With today’s technology you could easily have a fully capable PC strapped to your forearm, would that be useful?
Phone Like
Folding phones (originally popularised as Star Trek Tricorders) seem likely to have a long future ahead of them. Engineering technology has only recently developed to the stage of allowing them to work the way people would hope them to work (a folding screen with no gaps). Phones and tablets with multiple folds are coming out now [6]. This will allow phones to take much of the market share that tablets used to have while tablets and laptops merge at the high end. I’ve previously written about Convergence between phones and desktop computers [7], the increased capabilities of phones adds to the case for Convergence.
Folding phones also provide new possibilities for the OS. The Oppo OnePlus Open and the Google Pixel Fold both have a UI based around using the two halves of the folding screen for separate data at some times. I think that the current user interfaces for desktop PCs don’t properly take advantage of multiple monitors and the possibilities raised by folding phones only adds to the lack. My pet peeve with multiple monitor setups is when they don’t make it obvious which monitor has keyboard focus so you send a CTRL-W or ALT-F4 to the wrong screen by mistake, it’s a problem that also happens on a single screen but is worse with multiple screens. There are rumours of phones described as “three fold” (where three means the number of segments – with two folds between them), it will be interesting to see how that goes.
Will phones go the same way as PCs in terms of having a separation between the compute bit and the input device? It’s quite possible to have a compute device in the phone form factor inside a secure pocket which talks via Bluetooth to another device with a display and speakers. Then you could change your phone between a phone-size display and a tablet sized display easily and when using your phone a thief would not be able to easily steal the compute bit (which has passwords etc). Could the “watch” part of the phone (strapped to your wrist and difficult to steal) be the active part and have a tablet size device as an external display? There are already announcements of smart watches with up to 1GB of RAM (same as the Samsung Galaxy S3), that’s enough for a lot of phone functionality.
The Rabbit R1 [8] and the Humane AI Pin [9] have some interesting possibilities for AI speech interfaces. Could that take over some of the current phone use? It seems that visually impaired people have been doing badly in the trend towards touch screen phones so an option of a voice interface phone would be a good option for them. As an aside I hope some people are working on AI stuff for FOSS devices.
Laptop Like
One interesting PC variant I just discovered is the Higole 2 Pro portable battery operated Windows PC with 5.5″ touch screen [10]. It looks too thick to fit in the same pockets as current phones but is still very portable. The version with built in battery is $AU423 which is in the usual price range for low end laptops and tablets. I don’t think this is the future of computing, but it is something that is usable today while we wait for foldable devices to take over.
Another interesting thing that’s on offer is a laptop with 7″ touch screen beside the keyboard [13]. It seems that someone just looked at what parts are available cheaply in China (due to being parts of more popular devices) and what could fit together. I think a keyboard should be central to the monitor for serious typing, but there may be useful corner cases where typing isn’t that common and a touch-screen display is of use. Developing a range of strange hardware and then seeing which ones get adopted is a good thing and an advantage of Ali Express and Temu.
The PineTime is a nice smart watch from Pine64 which is designed to be open [15]. I am quite happy with it but haven’t done much with it yet (apart from wearing it every day and getting alerts etc from Android). At $50 when delivered to Australia it’s significantly more expensive than most smart watches with similar features but still a lot cheaper than the high end ones. Also the Raspberry Pi Watch [16] is interesting too.
Wwan hardware (for accessing the phone network) in M.2 form factor can be obtained for free if you have access to old/broken laptops. Such devices start at about $35 if you want to buy one. USB GPS devices also start at about $35 so probably not worth getting if you can get a wwan device that does GPS as well.
What We Must Do
Debian appears to have some voice input software in the pocketsphinx package but no documentation on how it’s to be used. This would be a good thing to document, I spent 15 mins looking at it and couldn’t get it going.
To take advantage of the hardware features in phones we need software support and we ideally don’t want free software to lag too far behind proprietary software – which IMHO means the typical Android setup for phones/tablets.
Support for changing screen resolution is already there as is support for touch screens. Support for adapting the GUI to changed screen size is something that needs to be done – even today’s hardware of connecting a small laptop to an external monitor doesn’t have the ideal functionality for changing the UI. There also seem to be some limitations in touch screen support with multiple screens, I haven’t investigated this properly yet, it definitely doesn’t work in an expected manner in Ubuntu 22.04 and I haven’t yet tested the combinations on Debian/Unstable.
ML is becoming a big thing and it has some interesting use cases for small devices where a smart device can compensate for limited input options. There’s a lot of work that needs to be done in this area and we are limited by the fact that we can’t just rip off the work of other people for use as training data in the way that corporations do.
Security is more important for devices that are at high risk of theft. The vast majority of free software installations are way behind Android in terms of security and we need to address that. I have some ideas for improvement but there is always a conflict between security and usability and while Android is usable for it’s own special apps it’s not usable in a “I want to run applications that use any files from any other applicationsin any way I want” sense. My post about Sandboxing Phone apps is relevant for people who are interested in this [19]. We also need to extend security models to cope with things like “ok google” type functionality which has the potential to be a bug and the emerging class of LLM based attacks.
I will write more posts about these thing.
Please write comments mentioning FOSS hardware and software projects that address these issues and also documentation for such things.
This is the second book in the Silo series, following on the Wool, which I recently read. I think to a certain extend this book is better than the first one — I certainly found it compelling. An excellent read that explains how the universe described in Wool came to be, but yet also sets the scene for the third book in the trilogy.
Shift
Hugh Howey
Dystopias
Penguin Group
April 13, 2023
The much anticipated prequel to bestseller Wool that takes us back to the beginnings of the silo. In a future less than fifty years away, the world is still as we know it. Time continues to tick by. The truth is that it is ticking away. A powerful few know what lies ahead. They are preparing for it.
Prompted by a comment from someone I present below the 10 thickest books in my personal library. I made no correction for hardcover vs softcover. Measured at center of book with mild compression
The Books in order. 10th thickest left, thickest on right
My top 10 books ended up being a bit of a mix
Three Fiction: 1 Science Fiction, 1 Fantasy, 1 annotated detective series
One giant book of Chess puzzles
Two books about lots of things. 500 Villages and 100 Museum Objects
Two biographic books about a National Leader during wartime
A book of social history
A book looking at big trends in all recorded history
The Countdown
10th – 58mm – The New Annotated Sherlock Holmes. Volume 2. 1878 pages. Softcover
The tallest, widest and book with the most pages. Has the original text in the centre with notes on the outside and lots of illustrations
9th – 60mm – Villages of Britain by Clive Aslet. 658 pages. Hardcover
1-2 pages on 500 English villages. Usually covers an interesting feature, event or person
8th – 61mm – Team of Rivals by Doris Kearns Goodwin. 916 pages. Softcover
A book on Abraham Lincoln’s Cabinet. Basis for the movie “Lincoln” and my book is a movie branded version
7th – 61mm – The Lord of the Rings by J R R Tolkien. 1192 pages. Softcover
My much battered single volume edition I’ve had since I was a kid.
6th – 63mm – Chess 5334 Problems, Combinations, and Games by Laszlo Polgar. 1104 pages. Softcover
Mostly pictures of chess positions (6 per page) and the solution. Almost no words
5th – 64mm – A History of the World in 100 Objects. 707 pages – Hardcover
Based on a Radio Series. Each object has a couple of very nice photos and then around 3 pages of text about it and where it came from. Very nice book.
A Science Fiction book about what happens when the Moon blows up.
3rd – 66mm – Why the West Rules – For now. 750 pages. Hardcover
A big idea history book with speculation about the future.
2nd – 69mm – Road to Victory. Winston S. Churchill 1941-1945 by Martin Gilbert. 1416 pages. Hardcover
Part of the huge 8 volume official biography of Churchill. Covering Pearl Harbor to VE Day.
1st – 72mm – Family Britain 1951-57 by David Kynaston. 776 pages. Hardcover
Part of an ongoing series of books about the social history of Britain from 1945 to 1979. Covers a lot of ordinary lives and major events are often seen via individual’s reactions rather than being covered directly.
Mo Gawdat was kind of a big deal, at IBM, Microsoft, and then Google. But he was unhappy, so he decided to take an engineering approach and try to systematically “solve for happy” and work out why adding more money, shiny objects, and adoration of others didn’t actually make him happy.
When I was walking in Memphis I was walking with my feet ten feet off of Beale Walking in Memphis But do I really feel the way I feel?
— Walking in Memphis, Marc Cohn
Gawdat argues that much of the narrative we all experience in our heads is a biological function from long ago, designed to help us identify and avoid threats. In fact, he argues that it is now often counter productive. As a solution, he proposes four techniques to tame your inner monologue:
Observe, but don’t participate in the dialog. That is, acknowledge thoughts that affect your happiness when they happen, but don’t participate in a dialog about the thought, just note it and move on.
Sometimes a thought will “stick” and you’ll end up in a loop. In those cases, consider the cause of the drama — what is the underlying issue that is stopping you from moving on? What train of thought brought you to it now? That creates an opportunity to reframe the thought, perhaps not as a positive one but at least one you can acknowledge and move on from.
Try to move on to thinking about something else. Gawdat describes a “priming technique” where you focus on something else for a few moments and it helps you break out of the cyclical thought. This is interesting to me, because I sometimes “get words stuck in my head” — the elogy for a friend; an important work email; and so forth. I find that writing those words down helps in those cases because I think they get stuck because I am worried I will forget them. The thought loop feels a bit like that too, the brain’s way of ensuring that we don’t forget something which seems very important.
Calm your thoughts in general, that is, meditate. He has an interesting suggestion here — just stop and observe the world around you. What is notable and interesting at the moment? What is unusual?
Gawdat also makes the point that there is more to you than just your thoughts. He works through a series of questions around what defines you as a person, applying two tests — if you can observe a thing, then that thing is not you; and if a thing can change and leave you unchanged, then that thing is not you. He reaches an interesting conclusion there but I wont ruin it for you.
This however is one of the areas where Gawdat makes readers uncomfortable according to many of the reviews of this book that I have read. This is because he deviates from a relatively concrete and well referenced discussion of how to self manage your thought processes, into a discussion of whether or not an afterlife exists. He returns to this theme later in the book as well.
Gawdat then moves on to asking you to assess what is actually important to you. What are you doing because of how other people see you (or how you want other people to see you) versus things that actually make you happy. He also reminds us that while we might feel like the main character in the movies of our lives, we are only supporting actors in everyone else’s life movie.
To be honest, this is about the point where Gawdat loses me a bit — he enters into a discussion of the meaning of time. The point he’s trying to make is that time is arbitrary and we should choose to be more patient and to live in the moment, but its a meandering path to get there. This point is then reinforced by discussing how we don’t control the things around us — the only things in our control are our own actions and attitude, so if we let things ruin our day then we’ve let go of the one thing we control. Carpe Diem I suppose?
Gawdat also asserts that our memories of prior events taint our interpretation of current and future events, which seems fair to me, but that these memories are also summaries not completely accurate records and that the brain is more likely to record negative memories than positive ones. He also asserts that we have a tendency to exaggerate risks when considering options. While this might be true for some people, I have definitely met people who seem incapable of estimating risks at all so its certainly not true for everyone. Either way, he encourages the reader to try to be rational about the actual risks presented by your inner monolog.
We are encouraged to focus on those less fortunate that you when you’re unhappy, which seems like reasonable if sometimes unsafe advice. If you’re being abused, don’t look for reasons to be happy compared to others! So only consider this advice if your basic life needs — food, shelter, safety, et cetera are being met.
This book is largely an exploration of the process Gawdat went through when processing the unexpected loss of his son during routine surgery, which is a recurrent theme in the book. While that is sometimes a helpful checkpoint, it also causes Gawdat to veer off into a discussion of the metaphysical for the last couple of chapers of the book. This is a frequent source of complaints in other online reviews of the book, but I’d say just skip those chapters if they bother you.
Overall I’d say this book was ok, but not great. It makes some interesting points about how much we should trust our inner monologue to be right, but I feel it could have made those points in a much more terse manner without losing anything. While helpful, the book lacks sufficient supporting research for the field it plays in I suspect.
Solve for Happy
Mo Gawdat
January 10, 2019
368
Solve for Happy is a startlingly original book about creating and maintaining happiness, written by a top Google executive with an engineer's training and fondness for thoroughly analyzing a problem.
Pretty good history of the books and TV/Movie adaptions including a little on the 1st Villeneuve movie. Fun with lots of quotes and seems well researched. 4/5
Uses simple language it works though the complexity of modern warfare, addressed to an imaginary political leader. Recent enough to include lessons from Russian’s invasion of Ukraine. Highly recommend 5/5
Now, I might be biased because I like John Scalzi’s stuff, but this book was really good. It starts slower than a normal Scalzi book, and takes a couple of chapters to really get going, but I am glad I was patient with it. Apart from that its a quick easy read. Its a typical Scalzi book, light hearted and fun. I think this one requires you suspend disbelief a little harder than others (except perhaps for Redshirts) but that doesn’t make it less enjoyable.
Starter Villain
John Scalzi
September 21, 2023
262
Meeting opened at 20:00 AEDT by Sae Ra and quorum was achieved.
Minutes taken by Neill
2. Log of correspondence
Add Authoriser to ANZ Direct Online – 417289 Linux Australia (Incorporated)
Ideally all council members would be authorised. To be authroised they will need copies/scans of a passport and a utility bill with an address. Take them to a JP to certify. Then scan and email to ANZ NZ. Russell will email instructions to the council members.
Possible donation to Linux Australia from disincorporation of Melbourne Functional Programming Association Incorporated
The money has been deposited. Linux Australia will consider an appropriate recognition.
Inquiry: running an information security conference (Purplecon)
The organisers are invited to submit a proposal and budget. Russell will email them.
OSI at FOSDEM, Open Source AI draft 0.5
URGENT Re: pyconau 2024 sub-committee request
The urgent PyConAU matter has been dealt with (it was about signing the venue contract).
New MoU with WordCamp Central
Sae Ra will sign the new MoU. It is functionally identical to the existing contract and makes no new commitments.
Please authorise my request for ANZ mobile app
WordCamp Sydney 2024 – Request to form a LA subcommittee
Proposal is still being discussed. One surprise is that the expected number of attendees is higher than the previous pre-covid conference.
Trialling Wise
DrupalAsia / DrupalCon Asia
Issue with contact form on LA website – investigations and possible way forward
Seeking Kiwi PyCon and NZ PUG information for the Linux Aus website
The current process needed for ANZ
Payment requests for DrupalSouth
3. Items for discussion
OSI board nomination
Miles Goodhew has agreed to be nominated. A draft candidacy statement was provided to the council.
Motion: That Linux Australia accept and recommend Miles Goodhew as our nominee for the OSI board elections
Moved: Sae Ra Germaine
Seconded: Russell Stuart
Result: Passed unanimously
WordCamp Subcommittee
Motion: That Linux Australia approves the formation of a WordCamp Subcommittee to run WordCamp 2024 with the following members:
Wil Brown – Lead Organiser (Chair)
Jordan Gillman – Organiser/Treasurer ( Treasurer)
Dee Teal – Organiser/Program Manager
Jo Minney – Organiser/Speaker Lead
Eva Devos – Organiser/Swag & Merch/WPSyd Community Rep
Sam Toohey – Organiser/After Party/WPSyd Community Rep
Moved: Sae Ra Germaine
Seconded: Andrew Pam
Result: Passed unanimously
4. Items for noting
5. Other business
Drupal sub committee update
Drupal South in three weeks! Good keynotes lined up. Second keynote is a Girls In Tech panel. Ticket sales are still coming in. Currently at 190 attendees. The expectation is to end up somewhere over 200. Have hit revenue targets for tickets, but sponsorship is down. It’s particularly difficult for NZ companies this year, and there are headwinds for tech in general. Currently looks like a 25k loss for the conference. Twice as many entries for the awards show. Many first time attendees, more clients than developers which has been a goal.
One proposal for future conferences is to consider ways to promote Drupal outside of the existing community by having a Drupal booth at other conferences e.g. FST Government Summits, Everything Open, Tech in Gov, EduTECH
Drupal Asia – Mike has been working with the Drupal Association to use the DrupalCon brand for the Asian Drupal conference. The Drupalm Association does not want to be the financial sponsor. Their preference would be to work with Linux Australia and licence the brand to Linux Australia. Licensing the brand would increase the chances of a successful conference. Mike would like to start a conversation with him, Linux Australia and the Drupal Association. From Linux Australia’s perspective this should basically fit into the template that we currently use for running conferences. We would need a budget that would account for the licensing fees, and some way of dealing with payments in whatever country/currency the conference is run in. Linux Australia will also need to make sure we can comply with any legal or taxation requirements. The first conference will most likely be in Singapore.
Admin team update
Working on the new list server. Seeing weird stuff with Fastmail, but it can’t be definitively blamed on Fastmail. Something seems to be happening before the mail gets to Fastmail. The new listserver will go live this weekend. The new server will have a much cleaner config and will be easier to troubleshoot the problems.
The admin team have also been working on the web server upgrade.
Next in the queue is looking at the VM servers.
Also need to make sure we have correct contact details for any subcommittee servers running on Linux Australia infrastructure.
Joomla sub committee update
THe conference is going well. Should make the minimum attendance budget, but may not get much more than that. Currently there are 14 confirmed attendees out of 20. There is an unexpected bonus sponsor. Several panel talks are planned as well as straight presentations.
The conference is now about two and a half weeks away.
PyCon AU sub committee update
Contract with MCEC has been signed by Joel, and payment has been made. The financial induction still needs to be done. Clinton will chase people up for that. There is some wriggle room in the contract for catering. A decision on that will be held until the number of attendees is known.
Flounder sub committee update
Has been meeting monthly. Low turnout, but different people and topics. People from both Australia and New Zealand, and even China. Mostly focussed on phones and mobile devices.
LUV sub committee update
Going quite well. Two online meetings and one physical meeting each month. One social meeting, the regular LUV meetings and an in person technical support meeting. Generally around six people at each meeting.
LUV still doesn’t have a definite plan for holding an election, but is aware that it should happen soon. Andrew will poke Alexar about this.
WordPress sub committee update
An invitation was not sent to the WordCamp organisers because of an oversight by the Secretary
6. In camera
One item was discussed in camera
7. Action items
Setup WordCamp Subcommittee Invite – Neill Cox
7.1 Completed Items
Calendar invites for subcommittee meetings – Neill Cox
Call for OSI board nomination [OSI Elections team]
bitwarden.com verification emails have gone AWOL [Steve Walsh]
Issue with contact form on LA website – investigations and possible way forward [Kathy Reid] – Joel has responded
Change to auDA domain name rules – request to make submission under LA banner [Kathy Reid] – Jonathan has responded
DrupalSouth coming up, and a few other proposals [David Sparks]
KPC 24 / Payment in excess of NZD5000 [Richard Shea] – Russell has responded
Possible donation to Linux Australia from disincorporation of Melbourne Functional Programming Association Incorporated [Les Kitchen] – Joel has responded
Approval for Xero invoice template [Nathan Morrow]
3. Items for discussion
Drupal South
May not make as much money as initially hoped. David would like to speak to the council about a few things. It would probably help if the Drupal South website had some text explaining why it would be good to attend the conference. An example from Everything Open: https://2024.everythingopen.au/attend/why-should-employees-attend/
PyConAU
Joel is a signatory for the contract. Chris is discussing one of the points in the contract, which may impact the budget.. We’re waiting for resolution of that before signing the contract.
The budget looks reasonable.
Russell has reviewed the budget. It seems conservative in regards to ticket sales and sponsorship, so the expected result will probably be better than what is outlined in the budget.
Motion: To establish PyConAU2024 as an event subcommittee in line with the budget provided
Moved: Joel
Seconded: Russell
Passed unanimously
OSI board nomination
We have been offered a chance to nominate for their board. Sadly, there is no one on the council who has enough time to take up the offer.
Open source Event (EO in Canberra)
Sae Ra will discuss this with Chris when possible. It’s from the … 2025 is not possible, but maybe they would like to bid for 2026.
Goals:
Neill: Improve communication with subcommittees. Support and encourage more in person activities.
Russell: Sorting out the New Zealand situation. Helping with EO.
Jonathan: Keep working on the grants program and related activities. Encourage community participation and the next generation of community members.
Andrew: Joined to provide some choice of council members and felt that I had something to offer at a national level. Goals: Capitalise on the new Everything Open name/brand. Use it to engage new people, expand the reach of the community and broaden our remit. Also, a focus on COVID safety at our events, including hybrid and remote attendance.
Jenny: Keen to put forward the point of a view of the less technical members. Explain what open source offers to people who are in the non-tech community. Encourage participation from women in our community. Engage with government agencies using open source as part of their programmes.
Sae Ra: Document Everything Open so she can just be an attendee one year. Begin a discussion of what needs to be done in the way of updating our constitution. Look at how we do awards to recognise effort done by people in support of our community.
Joel: Focus on portfolios for council members, picking up on the work done by Sae Ra two years ago (https://linux.org.au/wp-content/uploads/2021/12/Council-Portfolios-2021.pdf) . Do a “stocktake” of our subcommittees. Fix some problems with the website (especially the election system). Updating the constitution. Start working on a five year strategic plan in consultation with the other council members.
Sorting out NZ banking
We need some more people who can authorise payments in New Zealand. We also have some historical signatories that need to be rationalised. These are suspended signatories, who can be reactivated in the future if needed.
4. Items for noting
NSW Fair Trading return submitted
ASIC FORM 490 Change of Directors submitted
Stuart Robertson Financial (Joomla Reconnect 24) induction done.
5. Other business
6. In camera
7. Action items
Calendar invites for subcommittee meetings – Neill Cox
On Friday, 1st March, it will be exactly one year since I walked into
Zen Motorcycles, signed the
paperwork, and got on my brand new Energica Experia electric motorbike. I
then rode it back to Canberra, stopping at two places to charge along the
way, but that was more in the nature of making sure - it could have done the
trip on one better-chosen charging stop.
I got a call yesterday from a guy who had looked at the Experia Bruce has at
Zen and was considering buying one. I talked with him for about three
quarters of an hour, going through my experience, and to sum it up simply I
can just say: this is a fantastic motorbike.
Firstly, it handles exactly like a standard motorbike - it handles almost
exactly like my previous Triumph Tiger Sport 1050. But it is so much easier
to ride. You twist the throttle and you go. You wind it back and you slow
down. If you want to, the bike will happily do nought to 100km/hr in under
four seconds. But it will also happily and smoothly glide along in traffic.
It says "you name the speed, I'm happy to go". It's not temperamental or
impatient; it has no weird points where the throttle suddenly gets an extra
boost or where the engine braking suddenly drops off. It is simple to ride.
As an aside, this makes it perfect for lane filtering. On my previous bike
this would always be tinged with a frisson of danger - I had to rev it and
ease the clutch in with a fair bit of power so I didn't accidentally stall it,
but that always took some time. Now, I simply twist the throttle and I am
ahead of the traffic - no danger of stalling, no delay in the clutch gripping,
just power. It is much safer in that scenario.
I haven't done a lot of touring yet, but I've ridden up to Gosford once and
up to Sydney several times. This is where Energica really is ahead of pretty
much every other electric motorbike on the market now - they do DC fast
charging. And by 'fast charger' here I mean anything from 50KW up; the
Energica can only take 25KW maximum anyway :-) But this basically means I
have to structure any stops we do around where I can charge up - no more
stopping in at the local pub or a cafe on a whim for morning tea. That has
to either offer DC fast charging or I'm moving on - the 3KW onboard AC
charger means a 22KW AC charger is useless to me. In the hour or two we
might stop for lunch I'd only get another 60 - 80 kilometres more range on
AC; on DC I would be done in less than an hour.
But OTOH my experience so far is that structuring those breaks around where I
can charge up is relatively easy. Most riders will furiously nod when I say
that I can't sit in the seat for more than two hours before I really need to
stretch the legs and massage the bum :-) So if that break is at a DC charger,
no problems. I can stop at Sutton Forest or Pheasant's Nest or even
Campbelltown and, in the time it takes for me to go to the toilet and have a
bit of a coffee and snack break, the bike is basically charged and ready to
go again.
The lesson I've learned, though, is to always give it that bit longer and
charge as much as I can up to 80%. It's tempting sometimes when I'm standing
around in a car park watching the bike charge to move on and charge up a bit
more at the next stop. The problem is that, with chargers still relatively
rare and there often only being one or two at each site, a single charger
not working can mean another fifty or even a hundred kilometres more riding.
That's a quarter to half my range, so I cannot afford to risk that. Charge
up and take a good book (and a spare set of headphones).
In the future, of course, when there's a bank of a dozen DC fast chargers in
every town, this won't be a problem. Charger anxiety only exists because
they are still relatively rare. When charging is easy to find and always
available, and there are electric forecourts like the UK is starting to get,
charging stops will be easy and will fit in with my riding.
Anyway.
Other advantages of the Experia:
You can get it with a complete set of Givi MonoKey top box and panniers. This
means you can buy your own much nicer and more streamlined top box and it fits
right on.
Charging at home takes about six hours, so it's easy to do overnight. The
Experia comes with an EVSE so you don't need any special charger at home. And
really, since the onboard AC charger can only accept 3KW, there's hardly any
point in spending much money on a home charger for the Experia.
Minor niggles:
The seat is a bit hard. I'm considering getting the
EONE
Canyon saddle, although I also just need to try to work out how to get
underneath the seat to see if I can fit my existing sheepskin seat cover.
There are a few occasional glitches in the display in certain rare situations.
I've mentioned them to Energica, hopefully they'll be addressed.
Supercomputing Asia 2024 was held in Sydney from the 19th to 23rd of February with over 1,000 attendees, most of whom were from Australia, the United States, Singapore, Japan, Thailand, and Aotearoa New Zealand, with a notable exception from the conference was China given their importance to both supercomputing and Asia, and one speaker noted wryly that "Australia is now apparently part of Asia". The program consisted of plenary sessions in the morning and multiple streams in the afternoon of each day. My attendance was at the IBM Storage Scale User Group for the entirety of the first day, the HPC Leadership Forum on the second, Skills and Training on the third, and the Accelerated Data Analytics and Computing Institute (ADAC) symposium on the fourth. The Storage Scale User Group was useful for a roadmap of their systems (e.g., IBM Storage Scale System 6000, Fusion HCI) and case studies. The Leadership Forum and the ADAC symposium both gave an overview of some of the major systems in the region, which included the two largest systems, Frontier (no 1), Aurora (no 2), along with Fugaku (no 4).
Of note from Fugaku was a Hyperion study on their macroeconomic return on investment for their HPC which was between $63 to $91 per dollar invested, following the 2013 IDN study of HPC in general indicating $44 per dollar invested. The larger figure is explained because of the tighter integration with national objectives in the peak system. Also of note, a concurring with a report written in September 2022 ("Microprocessor Trend Usage in HPC Systems for 2022-2023") was the rise of systems using AMD CPUs and the ubiquity of CPU/GPU heterogeneity. Thailand's Supercomputing Centre of note, rising from a relatively small system to one with 31744 AMD CPUs, 704 A100s, and no 94 in the top500 with 50% of their operating revenue now coming from fee-for-service from "national interest" private industries. In Australia, there is the leadership from NCI in developing the Indo-Pacific Exascale Consortium, modelled after the EuroHPC Joint Undertaking effort.
About 50 people attended the talk I gave at SCAsia 2024 on "HPC Certification Forum & Skill Tree: An Update". There was quite an enthusiastic discussion that followed with several questions about micro-credentials, the potential use of OpenBadge as part of the certification process, and strong interest from several other HPC centres (UWA, CSIRO, NeSI) and Intersect in participating eco-system approach about using the skill tree approach for training content and contributing back. The potential of this sort of collaboration within Australia at the very least will be extremely valuable in improving the HPC on-boarding process for researchers. The talk also dovetailed with a poster presentation, "HPC Training Generates HPC Results", which pointed out longitudinal correlations between the two in terms of training sessions, computer hours, and job completion.
Running topics of note throughout the conference and especially in the plenary sessions (a nice quirk was that the voice of Siri, Karen Jacobsen, was the MC for these sessions), was a focus on AI/machine learning/LLMs and quantum computing. The former topic especially noted the advantages of GPUS which bodes well for our own large GPU partition. Differentiation must be considered between quantum computing and quantum computers; as a recent Spartan-citing paper pointed out quantum algorithms on "classical" computers (e.g., HPC) are preferable to quantum computers which are very much still in the experimental phase. To differentiate, quantum computing is any method to generate quantum effects whereby qubit states can exist in superposition (0,1, both) rather than binary states (0,1). The typical system to do quantum computing, or at least simulate it, is usually HPC. In contrast, a quantum computer uses a system that directly uses a quantum system. For example, GENCI in France uses a photonic computer, LRZ in Germany uses superconducting qubits, PSNC in Poland uses trapped ions, etc.
Opportunities to speak with vendors is always important and in particular longer discussions were held with Dell with their roadmap, DDN on their new filesystem, and Altair's HPCWorks application (which, at the moment, only operates with PBSPro). Notably, many vendors continue to make a pitch in favour of monopolisation under the guise of convenience ("we'll do everything for you") rather than interoperability. Special thanks are given to Xenon Systems for an evening hosted at L'Aqua on Cockle Bay Wharf.
Overall, attendance and participation at the conference were extremely valuable for direct knowledge improvements in storage, useful collaborations with other centres for HPC training, awareness of vendor products, system developments in Asia and US, and developing an understanding of the overall direction of AI/LLM and quantum computing in HPC environments.
Two very different groups of people are unfrozen into a post-apocalyptic Earth. A group of Astronauts and a group of Convicted Murderers. Good Sawyer story although a bit on the short side 3/5
A tour of various pieces of Infrastructure that supports our everyday lives. Mostly an introduction but with some strong opinions on funding and sustainability. 3/5
Bios of the Astronauts and the US space programme leading up to the accident and various problems that made it inevitable. Good but not extremely detailed. 4/5
The plan by two wayward youths to rob a Belgian nightclub goes awry but how does it connect to a murdered man? Interesting story that avoids Maigret’s point of view. 3/5
Meeting opened at 20:05 AEDT by Joel and quorum was achieved.
Minutes taken by Neill and Jonathan
2. Log of correspondence
Lodge Linux Australia Activity Statement October..December 2023
Scrutineers report
Fwd: Charity audit (NZPUG)
Xero reconciliations
Linux Australia – Subcommittee Update [actually Reconnect with Joomla Budget]
Council members should have received an email with more details, but basically the previous council had some questions about the budget that had been submitted. A revised budget has now been submitted for the council’s consideration.
The new budget contains no sponsorship and is surprisingly frugal in their estimates of catering expenses. The budget is so small that it is unlikely to be a problem for LA, and Joomla has run previous events that have accumulated a buffer.
Once we accept a budget for an event we take responsibility for the results, including the possibility of a loss.
Fwd: Third Party Public Liability Insurance [for KiwiPyCon]
Issue with contact form on LA website – investigations and possible way forward
Change to auDA domain name rules – request to make submission under LA banner
May I assign LA as registrant of drupal.org.au?
pyconau 2024 conference admin
Fwd: Reconnect with Joomla Event
Fwd: MHW Best Practice Program- Letter of Consent
3. Items for discussion
Welcome to new council members
Recap: Fortnightly meetings for council. Ideally no more than an hour. Agenda available to everyone before meeting. Please add items to the agenda before the meeting starts.
Every second meeting is a subcommittee meeting where each of our subcommittees are invited to come along and report on how things are going.
Sometimes we discuss things that are not yet public, which will be minuted in the In Camera section. This may be something like a code of conduct issue or possibly information that a conference has shared with us but is not ready to make public.
Discussion and comments from everyone present are welcome, but please keep in mind that we are trying to be done in less than an hour.
We use Zoom for meetings as it is currently the best option available to us, but we would be happy to use a suitable open source option instead.
Similarly we use Google drive for document storage, but would like to move to an open source equivalent.
Jenny and Andrew will need to supply Joel with their preferred google account so that Joel can share the 2024 council directory.
We have a number of tasks to perform at the start of the new year. One requirement is Director IDs.
Details of committee members need to go into Linux Australia’s register, access to which can be requested by any member. This needs to include name, date of birth and address. There will be a document which shows the required details.
All council members will receive email from the council mailing address. It is sometimes best to allow discussion by the council before firing off a response.
We also have a (matrix) chat channel for quick discussions.
Sae Ra is happy to walk people through the various things that the council works on during the year.
Could everyone come with a few dot points for the next meeting addressing why we have all chosen to be on the council and what we would like to achieve this year?
4. Items for noting
Would it be possible to get the AGM minutes up soonish rather than just before the AGM?
5. Other business
Motion that the LA council accepts the proposed budget for the Reconnect with Joomla 2024 event and establishes an event subcommittee for this.
Moved by: Joel
Seconded: Sae Ra
Result: Passed unanimously
auDA Response
Jonathan will prepare a draft response in consultation with Kathy Reid. To be published on the LA website and posted to email and/or social media.
There was a general discussion between the council with Sae Ra abstaining due to a conflict of interest.
Contact Form on the Linux Australia website
Joel will discuss this with Wil to get advice on the best way to resolve the problem.
Drupal.org.au domain name
It seems appropriate to transfer ownership of the domain to Linux Australia. Joel will respond to the email.
PyconAU
PyconAU is now a steering committee. Late today they provided a draft budget for their next pycon conference and have notified us of their core committee membership.
PyconAU would like to lock in their venue for their proposed dates in November 2024.
Motion by Joel: that the LA Council approve the venue contract for PyCon AU 2024, and pay the associated deposit.
Moved by: Joel
Seconded: Sae Ra
Result: Passed unanimously
Next steps: budget to be reviewed by LA Council over the next two weeks and be voted on at the next Council meeting.
MHW Best Practice Program – Letter of Consent requested by the auditor. He would like to pass Linux Australia’s details on to CPA Australia as part of the Best Practice Program.
Motion: that LA approve Russell to sign the informed written consent for the MHW participation in the CPA Australia Best Practice Program assessment..
Moved by Russell
Seconded: Neill
Result: Passed unanimously
Meeting Times – are we happy to continue with Wednesday evenings at 2000 AEDT
After a brief discussion there was no significant disagreement about running the meetings at the current time. When daylight savings finishes we will move to 1930 AEST.
Over the last few months, I upgraded my Debian machines from
bullseye to
bookworm. The process was
uneventful (besides the asterisk
issue described below), but I ended up reconfiguring several things afterwards in
order to modernize my upgraded machines.
Logcheck
I noticed in this release that the transition to
journald is essentially
complete. This means that rsyslog is no longer needed on most of my systems:
apt purge rsyslog
Once that was done, I was able to comment out the following lines in
/etc/logcheck/logcheck.logfiles.d/syslog.logfiles:
#/var/log/syslog
#/var/log/auth.log
I did have to adjust some of my custom logcheck rules, particularly the ones that
deal with kernel messages:
Then I moved local entries from /etc/logcheck/logcheck.logfiles to /etc/logcheck/logcheck.logfiles.d/local.logfiles
(/var/log/syslog and /var/log/auth.log are enabled by default when
needed) and removed some files that are no longer used:
Finally, I had to fix any unescaped | characters in my local rules. For example
error == NULL || \*error == NULL must now be written as error == NULL \|\| \*error == NULL.
Networking
After the upgrade, I got a notice that the isc-dhcp-client is now
deprecated and so I removed if from my system:
apt purge isc-dhcp-client
This however meant that I need to ensure that my network configuration
software does not depend on the now-deprecated DHCP client.
On my laptop, I was already using
NetworkManager for my main
network interfaces and that has built-in DHCP support.
Migration to systemd-networkd
On my backup server, I took this opportunity to switch from ifupdown to
systemd-networkd by
removing ifupdown:
apt purge ifupdown
rm /etc/network/interfaces
putting the following in /etc/systemd/network/20-wired.network:
On my Linode server, I did the same as on the backup server, but I put the
following in /etc/systemd/network/20-wired.network since it has a static
IPv6 allocation:
Also, if you haven't migrated to systemd-networkd yet and are still using
ifupdown with a static IP address, you will likely run into DNS
problems which
can be fixed using the following patch to /etc/network/if-up.d/resolved:
@@ -43,11 +43,11 @@ if systemctl is-enabled systemd-resolved > /dev/null 2>&1; then
fi
if [ -n "$NEW_DNS" ]; then
cat <<EOF >"$mystatedir/ifupdown-${ADDRFAM}-$interface"
-"$DNS"="$NEW_DNS"
+$DNS="$NEW_DNS"
EOF
if [ -n "$NEW_DOMAINS" ]; then
cat <<EOF >>"$mystatedir/ifupdown-${ADDRFAM}-$interface"
-"$DOMAINS"="$NEW_DOMAINS"
+$DOMAINS="$NEW_DOMAINS"
EOF
fi
fi
@@ -66,7 +66,7 @@ EOF
# ignore errors due to nonexistent file
md5sum "$mystatedir/isc-dhcp-v4-$interface" "$mystatedir/isc-dhcp-v6-$interface" "$mystatedir/ifupdown-inet-$interface" "$mystatedir/ifupdown-inet6-$interface" > "$newstate" 2> /dev/null || true
if ! cmp --silent "$oldstate" "$newstate" 2>/dev/null; then
- DNS DNS6 DOMAINS DOMAINS6 DEFAULT_ROUTE
+ unset DNS DNS6 DOMAINS DOMAINS6 DEFAULT_ROUTE
# v4 first
if [ -e "$mystatedir/isc-dhcp-v4-$interface" ]; then
. "$mystatedir/isc-dhcp-v4-$interface"
and make sure you have nameservers setup in your static config, for example
one of my servers' /etc/network/interfaces looks like this:
I moved my customizations in /etc/chkrootkit.conf to
/etc/chkrootkit/chkrootkit.conf after seeing this message in my logs:
WARNING: /etc/chkrootkit.conf is deprecated. Please put your
settings in /etc/chkrootkit/chkrootkit.conf instead: /etc/chkrootkit.conf
will be ignored in a future release and should be deleted.
sshd[6283]: pam_env(sshd:session): deprecated reading of user environment enabled
I changed the following in /etc/pam.d/sshd:
--- a/pam.d/sshd
+++ b/pam.d/sshd
@@ -44,7 +44,7 @@ session required pam_limits.so
session required pam_env.so # [1]
# In Debian 4.0 (etch), locale-related environment variables were moved to
# /etc/default/locale, so read that as well.
-session required pam_env.so user_readenv=1 envfile=/etc/default/locale
+session required pam_env.so envfile=/etc/default/locale
# SELinux needs to intervene at login time to ensure that the process starts
# in the proper default security context. Only sessions which are intended
I also made the following changes to /etc/ssh/sshd_config.d/local.conf
based on the advice of ssh-audit 2.9.0:
I ran into a problem with one of my servers where it would suspend
itself after a certain amount of time. This was due to default GDM behaviour
it turns out and while I could tell gdm not to sleep on inactivity,
I instead put the following in /etc/systemd/sleep.conf.d/nosuspend.conf to fully
disable systemd-based suspend or hibernate:
The only major problem I ran into while upgrading to bookworm is that I discovered
that Asterisk has been removed from stable and testing.
For some reason, this was not mentioned in the release notes
and I have not yet found a good solution.
If you upgrade to bookworm, be warned that the bullseye packages will remain
installed (and will work fine in my experience) unless you "clean them up" with
apt purge '~o' accidentally and then you'll have to fetch these old debs manually.
Using NetworkManager and systemd-resolved together in Debian
bookworm does not work out of the box. The first sign of trouble was these constant
messages in my logs:
avahi-daemon[pid]: Host name conflict, retrying with hostname-2
Then I realized that CUPS printer discovery didn't work: my network
printer could not be found. Since this discovery now relies on Multicast DNS,
it would make sense that both problems are related to an incompatibility
between NetworkManager and Avahi.
What didn't work
The first attempt I made at fixing this was to look for known bugs in Avahi.
Neither of the work-arounds I found worked:
The real problem turned out to be the fact that NetworkManager turns on full
mDNS support in systemd-resolved which conflicts with the mDNS support in
avahi-daemon.
You can see this in the output of resolvectl status:
Global
Protocols: -LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub
Link 2 (enp6s0)
Current Scopes: DNS mDNS/IPv4 mDNS/IPv6
Protocols: +DefaultRoute -LLMNR +mDNS -DNSOverTLS
DNSSEC=no/unsupported
Current DNS Server: 192.168.1.1
DNS Servers: 192.168.1.1
DNS Domain: lan
which includes +mDNS for the main network adapter.
The solution was to tell NetworkManager to set mDNS to resolve-only mode in
systemd-resolved by adding the following to
/etc/NetworkManager/conf.d/mdns.conf:
[connection]
connection.mdns=1
leaving /etc/avahi/avahi-daemon.conf to the default Debian configuration.
Verifying the configuration
After rebooting, resolvectl status now shows the following:
Global
Protocols: -LLMNR +mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub
Link 2 (enp6s0)
Current Scopes: DNS mDNS/IPv4 mDNS/IPv6
Protocols: +DefaultRoute -LLMNR mDNS=resolve -DNSOverTLS
DNSSEC=no/unsupported
Current DNS Server: 192.168.1.1
DNS Servers: 192.168.1.1
DNS Domain: lan
Avahi finally sees my printer (called hp in the output below):
$ avahi-browse -at | grep Printer
+ enp6s0 IPv6 hp @ myprintserver Secure Internet Printer local
+ enp6s0 IPv4 hp @ myprintserver Secure Internet Printer local
+ enp6s0 IPv6 hp @ myprintserver Internet Printer local
+ enp6s0 IPv4 hp @ myprintserver Internet Printer local
+ enp6s0 IPv6 hp @ myprintserver UNIX Printer local
+ enp6s0 IPv4 hp @ myprintserver UNIX Printer local
Meeting opened at 20:07 AEDT by Joel and quorum was achieved.
Minutes taken by Neill
2. Log of correspondence
Application to form a Kiwi PyCon 2024 subcommittee
RISC-V hardware for software development – grant application decision
Annual Report now out on socials
Linux Australia Sponsorship of NZ Python User Group
Linux Australia – Subcommittee Update (Drupal)
Lodge Linux Australia Activity Statement October..December 2023
Email issues
Forwarded to admin team for investigation
WRT Richard Shea/NZPUG LA Membership application
Application was received after the election opened. Put on hold until after voting closed.
Sponsorship agreement template, Code of Conduct, anything else?
Fwd: Charity audit
Details following induction (KiwiPyCon)
Many AGM registrations
Several redbubble sales
3. Items for discussion
Joomla Event – Reconnect with Joomla 2024
Friday 15th to Sunday 17th March
Relatively small event, not many attendees (20 – 60), low budget. Good to see them active again.
The catering costs in the budget seem very optimistic (perhaps because someone is sponsoring in kind?), we will ask for clarification.
AGM
Scheduled for this Saturday (20 Jan 2024). We had to make a correction to the time in Zoom because Zoom reported the wrong time.
4. Items for noting
Council election is now complete. The OCM position declaration will be finalised by the returning officer.
5. Other business
NZPUG Audit
The cost of providing an audit of NZPUG is estimated at being at least $3,000 and possibly more than $10,000. These costs seem very high in proportion to the benefit that the audit would provide.
Neither organisation has any realistic prospect of recovering funds as a result of the audit. In particular there is no benefit to LA. NZPUG might be able to recover some money.
MOTION: That we approve a grant of a maximum $3,000 to NZPUG to get an audit done.
MOVED: Russell Stuart
SECONDED: Wil Brown
RESULT: Motion Failed
Guarantor for KiwiPycon
The venue for KiwiPyCon is asking for a guarantor for the event. Hopefully the subcommittee will find a way around this. Russell will ask them to explore other options (references, insurance)
Everything Open Gladstone
Second keynote announced. Ticket sales are slow, but given they only opened the week before Christmas this is not surprising.
I know that people rave about GMail's spam filtering, but it didn't work for
me: I was seeing too many false positives. I personally prefer to see some
false negatives (i.e. letting some spam through), but to reduce false
positives as much as possible (and ideally have a way to tune this).
Here's the local SpamAssassin setup I
have put together over many years. In addition to the parts I describe here,
I also turn off
greylisting on my email
provider (KolabNow) because I don't want to have to
wait for up to 10 minutes for a "2FA" email to go through.
This setup assumes that you download all of your emails to your local
machine. I use fetchmail for this, though
similar tools should work too.
Three tiers of emails
The main reason my setup works for me, despite my receiving hundreds of spam
messages every day, is that I split incoming emails into three tiers via
procmail:
not spam: delivered to inbox
likely spam: quarantined in a soft_spam/ folder
definitely spam: silently deleted
I only ever have to review the likely spam tier for false positives, which
is on the order of 10-30 spam emails a day. I never even see the the
hundreds that are silently deleted due to a very high score.
This is implemented based on a threshold in my .procmailrc:
# Use spamassassin to check for spam
:0fw: .spamassassin.lock
| /usr/bin/spamassassin
# Throw away messages with a score of > 12.0
:0
* ^X-Spam-Level: \*\*\*\*\*\*\*\*\*\*\*\*
/dev/null
:0:
* ^X-Spam-Status: Yes
$HOME/Mail/soft_spam/
# Deliver all other messages
:0:
${DEFAULT}
I also use the following ~/.muttrc configuration to easily report false
negatives/positives and examine my likely spam folder via a shortcut in
mutt:
unignore X-Spam-Level
unignore X-Spam-Status
macro index S "c=soft_spam/\n" "Switch to soft_spam"
# Tell mutt about SpamAssassin headers so that I can sort by spam score
spam "X-Spam-Status: (Yes|No), (hits|score)=(-?[0-9]+\.[0-9])" "%3"
folder-hook =soft_spam 'push ol'
folder-hook =spam 'push ou'
# <Esc>d = de-register as non-spam, register as spam, move to spam folder.
macro index \ed "<enter-command>unset wait_key\n<pipe-entry>spamassassin -r\n<enter-command>set wait_key\n<save-message>=spam\n" "report the message as spam"
# <Esc>u = unregister as spam, register as non-spam, move to inbox folder.
macro index \eu "<enter-command>unset wait_key\n<pipe-entry>spamassassin -k\n<enter-command>set wait_key\n<save-message>=inbox\n" "correct the false positive (this is not spam)"
Custom SpamAssassin rules
In addition to the default ruleset that comes with SpamAssassin, I've also
accrued a number of custom rules over the years.
Finally, I wrote a few custom rules of my
own based
on specific kinds of emails I have seen slip through the cracks. I haven't
written any of those in a long time and I suspect some of my rules are now
obsolete. You may want to do your own testing before you copy these outright.
In addition to rules to match more spam, I've also written a ruleset to
remove false positives in French
emails
coming from many of the above custom rules. I also wrote a rule to get a
bonus to any email that comes with a patch:
describe FM_PATCH Includes a patch
body FM_PATCH /\bdiff -pruN\b/
score FM_PATCH -1.0
since it's not very common in spam emails
SpamAssassin settings
When it comes to my system-wide SpamAssassin configuration in
/etc/spamassassin/, I enable the following plugins:
Some of these require extra helper packages or Perl libraries to be
installed. See the comments in the relevant *.pre files or use this
command to install everything:
as well as manual score
reductions
due to false positives, and manual score
increases
to help push certain types of spam emails over the 12.0 definitely spam
threshold.
Finally, I have the FuzzyOCR
package installed since it has
occasionally flagged some spam that other tools had missed. It is a little
resource intensive though and so you may want to avoid this one if you are
filtering spam for other people.
As always, feel free to leave a comment if you do something else that works
well and that's not included in my setup. This is a work-in-progress.
Way back in the distant past, when the Apple ][ and the Commodore 64 were king, you could read the manual for a microprocessor and see how many CPU cycles each instruction took, and then do the math as to how long a sequence of instructions would take to execute. This cycle counting was used pretty effectively to do really neat things such as how you’d get anything on the screen from an Atari 2600. Modern CPUs are… complex. They can do several things at once, in a different order than what you wrote them in, and have an interesting arrangement of shared resources to allocate.
So, unlike with simpler hardware, if you have a sequence of instructions for a modern processor, it’s going to be pretty hard to work out how many cycles that could take by hand, and it’s going to differ for each micro-architecture available for the instruction set.
When designing a microprocessor, simulating what a series of existing instructions will take to execute compared to the previous generation of microprocessor is pretty important. The aim should be for it to take less time or energy or some other metric that means your new processor is better than the old one. It can be okay if processor generation to generation some sequence of instructions take more cycles, if your cycles are more frequent, or power efficient, or other positive metric you’re designing for.
Programmers may want this simulation too, as some code paths get rather performance critical for certain applications. Open Source tools for this aren’t as prolific as I’d like, but there is llvm-mca which I (relatively) recently learned about.
llvm-mca is a performance analysis tool that uses information available in LLVM (e.g. scheduling models) to statically measure the performance of machine code in a specific CPU.
So, when looking at an issue in the IPv6 address and connection hashing code in Linux last year, and being quite conscious of modern systems dealing with a LOT of network packets, and thus this can be quite CPU usage sensitive, I wanted to make sure that my suggested changes weren’t going to have a large impact on performance – across the variety of CPU generations in use.
There’s two ways to do this: run everything, throw a lot of packets at something, and measure it. That can be a long dev cycle, and sometimes just annoying to get going. It can be a lot quicker to simulate the small section of code in question and do some analysis of it before going through the trouble of spinning up multiple test environments to prove it in the real world.
So, enter llvm-mca and the ability to try and quickly evaluate possible changes before testing them. Seeing as the code in question was nicely self contained, I could easily get this to a point where I could easily get gcc (or llvm) to spit out assembler for it separately from the kernel tree. My preference was for gcc as that’s what most distros end up compiling Linux with, including the Linux distribution that’s my day job (Amazon Linux).
In order to share the results of the experiments as part of the discussion on where the code changes should end up, I published the code and results in a github project as things got way too large to throw on a mailing list post and retain sanity.
I used a container so that I could easily run it in a repeatable isolated environment, as well as have others reproduce my results if needed. Different compiler versions and optimization levels will very much produce different sequences of instructions, and thus possibly quite different results. This delta in compiler optimization levels is partially why the numbers don’t quite match on some of the mailing list messages, although the delta of the various options was all the same. The other reason is learning how to better use llvm-mca to isolate down the exact sequence of instructions I was caring about (and not including things like the guesswork that llvm-mca has to do for branches).
One thing I learned along the way is how to better use llvm-mca to get the results that I was looking for. One trick is to very much avoid branches, as that’s going to be near complete guesswork as there’s not a simulation of the branch predictor (at least in the version I was using.
The big thing I wanted to prove: is doing the extra work having a small or large impact on number of elapsed cycles. The answer was that doing a bunch of extra “work” was essentially near free. The CPU core could execute enough things in parallel that the incremental cost of doing extra work just… wasn’t relevant.
This helped getting a patch deployed without impact to performance, as well as get a patch upstream, fixing an issue that was partially fixed 10 years prior, and had existed since day 1 of the Linux IPv6 code.
Naturally, this wasn’t a solo effort, and that’s one of the joys of working with a bunch of smart people – both at the same company I work for, and in the broader open source community. It’s always humbling when you’re looking at code outside your usual area of expertise that was written (and then modified) by Really Smart People, and you’re then trying to fix a problem in it, while trying to learn all the implications of changing that bit of code.
Anyway, check out llvm-mca for your next adventure into premature optimization, as if you’re going to get started with evil, you may as well start with what’s at the root of all of it.
After a three year break, I spoke at five conferences in the last twelve months:
RubyConf Thailand — a wonderful second edition of this event, the chance to share Hanami 2 on the stage for the first time, and first-time in person hangs with another Buildkiter!
RubyConf AU — a joyous reunion for my home community. Good to be back, and positive signs for the future. Met many Buildkiters in person here!
Brighton Ruby — I’ve admired Andy and this event for the longest time. To attend and contribute a talk was a dream come true.
RubyConf — my first time at the US-based RubyConf, and a brilliant time all around: made new friends, had many great conversations, and got to work with some first-time Hanami contributors during the hack day!
RubyConf Taiwan — What a revelation! A whole thriving Ruby community I had no idea about, and a conference was chock-a-block with interesting talks. Being able to keynote opposite Matz was a real honour.
I’d commend any of these conferences to you, and I hope to get back to each of them in the future.
Being able to talk at so many events was definitely not my plan at the outset of the year! But one thing led to another, and I just rolled with it. It was a pleasure to share Hanami with people in so many places.
One thing I appreciated over this period was the chance to refine my method of introducing Hanami, and moreover, how I deliver conference talks in general. I’m very happy with how this ended up. I ended the year giving two very different presentations, each in their own way imbuing the audience (I hope!) with a sense of both whimsy and possibility: one involved song and dance, and the other, a surprise costume reveal!
A near-release of Hanami
Back at the end of 2021, we made a big push to get Hanami 2.0 released before I made it to RubyConf Thailand, and we succeeded!
I then spent all of 2022 working towards Hanami 2.1, which would introduce our view layer and a completely new approach to handling assets. As RubyConf approached in November, we attempted to do the same thing, to use the conference as motivation and make a big push to get the release out. I spent 2+ months working every night and weekend towards this, and we got so close, but didn’t quite make it.
Just two days before my talk, while I was already at the conference, we discovered what turned out to a release-blocking issue with our front end assets compilation. After a scramble at various stopgap fixes, we decided nothing would quite cut the mustard, and deferred the release. This was disappointing, but was the best choice for the project. After a break over Christmas, I’m now ready to take a final pass at this and make the right choices for the future.
Given this, I hope for 2024 to be a big two-release year for Hanami, with 2.1 happening next month, followed by 2.2 whenever it’s ready.
Family trips!
Once the Brighton Ruby opportunity came up, we decided to make the most of it and turn it into a family trip to Europe, our first overseas trip in the post-2020 era. It was an excellent time. We got to spend a bonus summer across Brighton, London, Paris, Amsterdam, Rotterdam and Brussels. The kids travelled very well, and we all can’t wait to do it again.
We also took a few nice road trips over the year, visiting Orange, Wagga Wagga, and ending the year with a relaxing week over Christmas in a house at Bawley Point.
Work at Buildkite
I had a good year at Buildkite. I spent the year in the same team I joined in 2022. Early in the year we hired some folks and brought the team to its full complement. Everyone is lovely, and we put in some great work towards fourdifferentquarterlyreleases.
I reached my first “bikkiversary” milestone in July, I joined an active on-call roster for the first time, I helped establish some clear direction for our future in front end development, and ended the year acting as an engineering manager, just to help keep things steady while my existing manager took some leave. Every one of these has been a pleasure. I’m continually humbled by the talent that surrounds me at Buildkite, and I’m looking forward to another year of learning.
Best of all, we gathered for our BIPOP (Buildkite In-Person On-site Party; yes, we love acronyms), our whole-company event in Cairns. This was a blast.
Reading
I read 22 books. In order:
Distress, Greg Egan
Sea of Tranquility, Emily St. John Mandel
The Water Knife, Paolo Bacigalupi
Shards of Earth, Adrian Tchaikovsky
Eyes of the Void, Adrian Tchaikovsky
The Thousand Earths, Stephen Baxter
Eversion, Alastair Reynolds
Lords of Uncreation, Adrian Tchaikovsky
Fractal Noise, Christopher Paolini
Me, Ricky Martin
Ancillary Justice, Ann Leckie
Ancillary Sword, Ann Leckie
Ancillary Mercy, Ann Leckie
Provenance, Ann Leckie
Translation State, Ann Leckie
Creation Node, Stephen Baxter
The Spare Man, Mary Robinette Kowal
Some Desperate Glory, Emily Tesh
Fugitive Telemetry, Martha Wells
System Collapse, Martha Wells
Fourth Wing, Rebecca Yarros
Iron Flame, Rebecca Yarros
I enjoyed them all! Adrian Tchaikovsky’s Final Architecture trilogy was thrilling, and discovering Ann Leckie’s Imperial Radch world was a true wonder: I’m so glad I got to binge all five stories together. It was a joy to revisit Murderbot with the most recent two books, and I don’t think I’ve read anything faster than I did Fourth Wing while hanging around a coast house at Christmas.
This year I also figured out my ideal e-reading situation. It’s the iPad mini, and Apple’s Books app in particular. Nothing beats its responsiveness and ease of use. And the iPad mini helps with the occasional tech book I read too. And thanks to Calibre and the Obok plugin, I can also buy books from Kobo and get them into Apple Books in short order.
Assorted things
We ended the year by giving the kids (9 & 7) each their own bedrooms. My desk/office is once again located next to my bed. Given I did this for three years already in our previous apartment, I expect this to work out well enough.
I started using the Retro app to share photos with a small group of friends. It’s brilliant! It has me sharing photos much more regularly, and helped me end the year with a nice collection of memories.
Thanks to several long plane rides, I did a decent amount of movie watching. Notables: No Time to Die (sob), Shotgun Wedding (fun), Jules (surprising), and Indy 5 (a triumph). Best soundtracks? Tetris, The Thomas Crown Affair.
I continue to pay attention to the little computer on my wrist telling me to exercise, though this unfortunately wavered towards the end of the year during my crunch on Hanami and conference talks.
Meeting opened at 20:02 AEDT by Joel and quorum was achieved.
Minutes taken by Neill
2. Log of correspondence
RISC-V hardware for software development – grant application decision
Payment Approval Request – DrupalSouth Community Day
A couple of website and social updates in preparation for AGM / elections
Open Source AI Definition: Version 0.0.3 released, planning a global outreach
Hack the Triangle Workshops – grant application decision
Application to form a Kiwi PyCon 2024 subcommittee
BAS Time
[Linux-aus] contest proposal
3. Items for discussion
MOTION: Linux Australia accepts the provisional budget for 2024.
MOVED BY: Russell Stuart
SECONDED: Neill Cox
OUTCOME: Motion passed unanimously
Kiwi PyCon subcommittee for 2024
MOTION: Linux Australia accepts Kiwi PyCon XIII (2024) as an event subcommittee, per the proposal provided.
MOVED BY: Joel
SECONDED: Jonathan
OUTCOME: Motion passed unanimously
One motion passed in camera, to be released later.
Programming Contest Proposal – Linux Aus mailing list
The council is generally supportive of this, but it is something for the next council to decide the details of, given a proposal is still forthcoming. It has been good to see a discussion of this sort on the mailing list.
3. To receive the REPORTS of activities of the preceding year from OFFICE BEARERS
MR JOEL ADDISON – President
MR CLINTON ROY – Secretary
MR RUSSELL STUART – Treasurer
Includes presentation of the Auditor’s Report
Question from Miles to Clinton about notifications/emails. Clinton responds that it’s only one or two a day generally, but during times of great upset, it’s a lot of time to deal with complicated questions.
Question from Sae Ra to Russell, is LA going to be able to stick with the 6% LA tax, or are we going to have to raise it. Russell says it’s very hard, this year it was near 7%, and that is without the fairly expensive face-to-face; which is an important event for new council members. Russell would be in favour of raising it to keep such important activities happening.
Question from Katie about the election, the window was only nine days, was quorum achieved. Joel responds that the scrutineers report is at the end of the agenda. We don’t have a high quorum required, so it was easily achieved. End of voting date was earlier this year than when we ran AGM in person, but similar to last year. This was done to give Council time to prepare everything, especially for the returning officer. Joel apologises for not opening and advertising it earlier.
Question from Hamilton: Does Linux Australia still support OpenInfra Foundation? No one on council can remember any interactions this year, Joel will look into it.
Question from Hamilton: Will Linux.org.au Elections extension have [an] option to allow nominees to be emailed to accept nomination? That will be added to a list of things the council wants to update, including mail outs, and making the interface easier.
MOTION by RUSSELL STUART that the Auditor’s Report is a true statement of financial accounts. Seconded by Joel Addison.
26/26 voted
Yea 26 92%
Nay 0 0%
Abstain 2 8%
Motion is passed.
MOTION by JOEL ADDISON that the President’s report is correct. Seconded by Russell Stuart.
26/26 voted
Yea 23 88%
Nay 0 0%
Abstain 3 12%
Motion is passed.
MOTION by CLINTON ROY that the Secretary’s report is correct. Seconded by Jonathan Woithe.
26/26 voted
Yea 23 88%
Nay 0 0%
Abstain 3 12%
Motion is passed.
MOTION by RUSSELL STUART that the Treasurer’s report is correct. Seconded by Wil Brown.
26/26 voted
Yea 23 88%
Nay 0 0%
Abstain 3 12%
Motion is passed.
MOTION by JOEL ADDISON that the actions of Council during 2022 are endorsed by the membership. Seconded by Neill Cox.
24/26 voted
Yea 24 92%
Nay 0 0%
Abstain 2 8%
Motion is passed.
4. To CONSIDER items tabled in the call for agenda items
MOTION by Kathy Reid that the Linux Australia community endorse the actions of Council 2022 and thank them for their valued volunteer service. Sae Ra Germaine seconds the motion.
26/26 voted
Yea 22 85%
Nay 0 0%
Abstain 4 15%
Motion is passed.
MOTION by Craige McWhirter that after discussion of the merits of changing
titles from President / Vice President to Convenor / Co-Convenor that the
meeting chair tests the meeting for consensus that the suggested change is
worth including in the constitutional review, falling back to a vote if
consensus is blocked. Paul Wayper seconds the motion.
As mentioned in the motion, discussion on the merits of changing the name was opened.
Sae Ra comments that having certain role names in the organisation makes us look more professional. Wil comments that these role names are in the constitution, and would require a referendum to change. Jonathan comments that everyone knows what a president of an organisation is, but not a lot of people know what a convenor is, we should stick with the standard terms used elsewhere. Hamilton, used to be president of a musical society, easy to communicate with other entities with a well known role name. Kathy advocates against the motion, LA gives career experience to those that sit on council, and it looks better on the CV as the current role names that people understand, not as useful with the proposed role names. Steve thinks there are defined titles required by the corporations act, such as president, chair etc. and that even if this motion gets through, we might not be able to make such a change to the constitution. The original email with the motion and some motivations gets mentioned, wanting a flatter organisation, which is more in line with FLOSS organisations. Consensus was that a change in the titles is not desired.
A vote on the motion was then held, with people voting on whether they agree with changing the titles.
26/26 voted
Yea 1 4%
Nay 22 85%
Abstain 3 12%
Motion has failed.
5. DECLARATION of Election and WELCOME of incoming Council by the Returning Officer
Returning officer is Julien Goodwin.
See Appendix 1 for the Scrutineers Report. Julien delivers the report verbally to those in attendance.
Hamilton notes that the system is rather complicated to attempt to install, compared to standard wordpress. Why was this system picked? Kathy responds, part one, a number of factors went into the decision, what would the member system sit on top of, at the time there were more skills with wordpress. The second part, the elections module was a commissioned piece of work, a plugin to the system that we had. We decided to use open source solutions to align with LA’s values. Steve responds, this is a module within wordpress, it’s tightly entwined with a particular version of php, and Steve spent a chunk of time porting the module from Agileware hosted website to our own hosting. Steve has a bunch of notes on how this would be done, and is happy to share those with those willing to update the plugin.
Joshua asks what data was left behind, Julien responds it’s metadata of previous votes, with enough data linking, it could be used to determine voters from previous elections. The admin team have been tasked with cleaning it up.
6. NOMINATION and ELECTION of Members to Vacant Council Positions
All positions were filled during the original election, so no nomination or election was held during the meeting.
7. To HEAR and RESPOND to questions from the floor
Jonathan noted that the role name motion was about allowing a discussion on the issue at the meeting. However, when the vote was taken it was treated as a vote on including the role name issue in the constitutional review (the consensus test). A further discussion makes it clear that the vote was a good enough consensus guage: that the consensus of the meeting was to not include the role names in the constitutional review.
Appendix 1 – Scrutineers report
Julien Goodwin, January 20, 2023
Dear Council,
As Returning Officer for the 2023 Council Election I am taking on a duty to ensure that;
The Election has been run in line with the Linux Australia Constitution
That the results of the Election have been scrutinised, and appropriate checks made to satisfy a reasonable person that the integrity of the Election has been upheld
And to report my findings, adverse or otherwise, to Council, who are responsible to act on those findings
This email serves as a record of the actions taken to ensure the above, and serves as a formal process for Returning Officers to follow in years to come.
In summary my findings are that:
The election has been run in line with the Linux Australia Inc., Constitution as per the Linux Australia website
The results of the Election have been scrutinised, and I am satisfied that the integrity of the Election has been upheld
The results are summarised below
The recommendation from previous years that the CiviCRM election module eliminate candidates who are elected to lower-ranked positions if they are already elected to a higher ranked position is still required.
Detailed notes follow. These notes include PII references that will need to be redacted if this report is presented to members.
Julien Goodwin
January 20th 2023
Compliance with the Constitution
S(15) of the Constitution stipulates the following requirements, which I have validated:
Nominations of candidates and their consent to be nominated is handled via the CiviCRM election module; no manual check done
The number of nominations exceeds the number of positions, and a ballot is being held, via the CiviCRM election module
The ballot cannot be conducted more than 60 days before an AGM; the AGM is 21 January 2023, the ballot occurred after nominations closed on 8 January 2023. This is in line with the Constitution.
A person nominated to Council must be a current member of Linux Australia, Inc. This is enforced by the CiviCRM election module; no manual check done
I am satisfied that the Constitution has been complied with.
At this rate, there is no real blogging here, regardless of the lofty plans to starting writing more. Stats update from Hello 2023:
219 days on the road (less than 2022! -37, over a month, shocking), 376,961km travelled, 44 cities, 17 countries.
Can’t say why it was less, because it felt like I spent a long time away…
In Kuala Lumpur, I purchased a flat (just in time to see Malaysia go down), and I swapped cars (had a good 15 year run). I co-founded a company, and I think there is a lot more to come.
2024 is shaping up to be exciting, busy, and a year, where one must just do.
Since late in 2007 I have been involved in the field of high performance computing. Initially, this was at the Victorian Partnership for Advanced Computing, but just before that organisation closed its doors in December 2015 I accepted a similar role at the University of Melbourne. The end of the year provides a reason for reflection, an annual report if one likes, and whilst activities not related to my vocation and profession will be dealt with in a subsequent entry, the opportunity is taken here to review workplace activities and in particular, changes in the environment for the University's general HPC system, Spartan. Spartan now has 6159 accounts across 2109 projects in diverse disciplines in the life sciences, engineering, economics, mathematics, and more and has been cited in 62 papers in the past year.
Some of those papers led to presentations to the Research Computing Services (RCS) team through the Cultural Working Group (CWG), which I have chaired for the past two years and held responsibility for organising these talks. In total six presentations were held this year, with a personal favourite on the use of AI algorithms, a supercomputer (Spartan), and robotics to sort plastic waste from two researchers at the Department of Infrastructure Engineering. The CWG was formed in 2020 following recognition from a staff survey that not all was well in RCS in terms of staff awareness of the group's objective, work between the different groups within the RCS, transparency in decision-making, involvement, and influence in decisions, career-progression opportunities, and job security. The staff-led CWG (with one management representative) made a concerted effort across those targetted areas and, following a survey in the middle of this year, substantial improvements were found in every criterion. At the end of this year, just after the last tech/researcher presentation, it brought great pleasure to say that whilst operations would continue, the group had succeeded in achieving its objectives and could close down as a formal body and as a successful project.
A very large part of my role at the University consists of training various postgraduate and postdoctoral researchers on how to use the system. This year included some 24 days of workshops involving close to 500 participants, roughly on par with other years and deliberately pulling back a bit from the first year of COVID, when over 40 of such workshops were conducted. Of particular note was early in the year a review was conducted of usage from those who had received training the previous year, resulting in the very surprising metric that at least 54.14% of cluster utilisation in 2022 was conducted by users after they had received training. I have always emphasized how important HPC training is but it was astounding to see such a metric as proof. As another form of training this year I continued with my regular activity as a guest lecturer and tutor for the master's level course Cluster and Cloud Computing. My role in this, previously just a single lecture, has now been extended to six lectures and workshops and is likely to expand in 2024. I must also mention here a presentation on RCS services to the Quantitative and Applied Ecology Research Group, with a future paper in development from that body on software citations.
Another major part of my role is scientific software optimisation and installation. Apart from the usual work in this field this year had the bonus of Spartan receiving its first major operating system upgrade since it was first turned on in 2015. Changing the underlying major release of the operating system (and indeed, jumping from RHEL v7 to v9) required existing software to be recompiled. In a one-month period, working with demonic fury, I was primarily responsible for around 500 software builds and an expansion in job submission examples. At the same time, Spartan also finally had the opportunity to run the LINPACK tests to be recognised as one of the world's supercomputers. It was an award that was long overdue (we've had sufficient performance to be on that list for years) and even then the certificate was for only part of the entire system.
Other activities included establishing the Spartan HPC Champions group among power-users of the system who can provide training advice to other members of their research teams, and continued involvement as a Board member of the international HPC Certification Forum and as an irregular contributor to the EasyBuild code repository. I have no doubt that these and other activities will all continue in 2024, however, there will be an additional role as well, following a necessary and considered restructure of RCS, I have found myself as the recipient of a small promotion in role and responsibility. It will be a position I will take with the appropriate seriousness; after all, supercomputing is one of those activities that has made a massive change to improving the world and will continue to do so. For the technical staff, it can be challenging and rewarding as they provide the researchers the tools to make great discoveries and inventions. But those staff also need to be in an environment where they feel secure and can flourish - and that means listening to their technical advice, as they actually do know best for such matters. This will be certainly the most significant challenge in the coming year.
Meeting opened at 20:05 AEDT by Joel and quorum was achieved.
Minutes taken by Neill
2. Log of correspondence
Steve Walsh: admin team reimbursements
Russell Stuart: Draft Proposals (Kiwi PyCon XIII)
Russell Stuart: Supporting documents for Kiwi Pycon 2024
Meetup: Meetup Invoice AU2023-16828
Michael Richardson: DrupalSouth Community Day Budget
Russell Stuart: Linux Australia’s 2022/2023 audit
Russell Stuart: Tax invoice attached (for audit)
3. Items for discussion
Motion: The treasurer and president sign the following statement from the auditor:
Principal activities Linux Australia is the peak body for Linux User Groups (LUGs) around Australia, and as such represents approximately 5000 Australian linux users and developers. There have been no significant changes in the state of affairs of the association during the year.
Operating Result The profit of the association for the financial year after providing for income tax amounted to $123,426. Significant changes in state of affairs There have been no significant changes in the state of affairs of the association during the year. Events after the reporting date No matters or circumstances have arisen since the end of the financial year which significantly affected or may significantly affect the operations of the association, the results of those operations or the state of affairs of the association in future
financial years. Signed in accordance with a resolution of the members of the committee: (president & treasurer).
MOVED BY: Russell Stuart
SECONDED: Sae Ra
Outcome: Passed unanimously
MOTION: The treasurer signs the engagement letter from our auditor
Their cover letter said: It is a best practice in our industry that all work is undertaken is covered by an up-to-date and relevant engagement letter – we always endeavour to operate at the highest standard of doing business. This letter ensures we both have a common understanding of what is required to be delivered, for what charge and also lists our general terms of doing business and also anything specific to the services you have requested. But perhaps the main reason is they want us to acknowledge the price rise from $5500 to $6050. The previous price rise was in 2016.
MOTION: The treasurer signs the auditors engagement letter.
MOVED BY: Russell Stuart
SECONDED: Joel
Outcome: Passed unanimously
Grant applications to be discussed
RISC-V, smart-watch and tablet computing development, from Russell Coker and Yifei Zhan. Funding applied for: $1600
MOTION: Council approves the grant application from Russell and Yifei to purchase hardware as described in the grant application.
MOVED: Joel
SECONDED: Wil
OUTCOME: Motion failed.
Russell and Yifei are encouraged to provide a more detailed proposal for the consideration of next year’s council.
RISC-V hardware for FOSS database development, from David Williams. Funding applied for: $2117.40
MOTION: Council approves the grant application from David Williams to purchase hardware as described in the grant application.
MOVED: Joel
SECONDED: Neill
OUTCOME: Failed with one abstention.
David has provided a detailed proposal. Only one response from the membership has been received and it advocated for the $2,117.40 option.
David is encouraged to provide a clearer explanation of which databases and what target distribution is intended.
Hack the Triangle workshops, from Lyndsey Jackson. Funding applied for: $2000
MOTION: Council approves the grant application from Lyndsey Jackson to run the workshops as per the grant application, subject to there being clear application and promotion of open source values and resources.
MOVED: Joel
SECONDED: Wil
OUTCOME: Motion passed
4. Items for noting
5. Other business
Call for Nominations
Opening the election will happen on 26 December. Slightly delayed due to technical issues. The announcement email can be sent now to give the members as much notice as possible.
AGM
Will be announced in the election email
EO2024
Code of Conduct – Sae Ra will convene the code of conduct team to review and respond to any items raised.
The organising team is now operating better, and items are progressing positively.
Meeting opened at 20:07 AEST by Joel and quorum was achieved.
Minutes taken by Neill.
2. Log of correspondence
2023-11-23 Xero reconciliations
2023-11-27 Action needed for your Wise Business account – Russell has responded Note: This also required supplying birth dates for various council members.
2023-11-24 Linux Australia’s 2022/2023 audit
2023-11-24 Activity Statement from ATO Portal for the auditor – From Russell. The required activity statement has now been provided.
2023-11-29 Grant Application from Russell Coker for RISC-V, smart-watch, and tablet computing development
2023-11-29 Report for Linux Australia grant: Pinephone development
2023-11-30 Report for Linux Australia grant: Girls Canberra #1
2023-11-30 Grant Application from Lyndsey Jackson for Hack The Triangle Digital Skills Holiday Workshops
2023-11-30 Audit documents
2023-12-01 Grant Application from David M Williams for RISC-V hardware
2023-12-01 Grant program update
3. Items for discussion
Kiwi PyCon 2024
Application will be forthcoming for Kiwi PyCon 2024 to run under the auspices of Linux Australia
4. Items for noting
Jonathan now has all the grant reports and will forward them to the appropriate person for inclusion in the LA Annual Report.
5. Other business
Drupal subcommittee update
Canberra Community day
good feedback, went well. Had a waiting list. 112 registrations when the target was 80. 86 people actually attended on the day. Post event survey has had limited responses but they were positive.
Budget not finalised yet, but looks like break even or perhaps a small profit.
Helped that it was held the day after the GovCMS event. Approx 60% government employees and 40% Drupal agencies. Those government attendees indicated that they would attend if it was held in Canberra again, but less likely to travel.
Sydney: planning going well about half of the sponsorships are sold. Seems people may be struggling
85/88 talk submissions which is typical for the larger Australian conferences. Track chairs are happy with quality.
Will be unable to bring someone over from the Drupal Association for a keynote. But may be able to do a panel. Still looking for a few more keynote speakers.
The Drupal subcommittee is also looking for other conferences to attend to promote Drupal South.
The Drupal South Subcommittee will try and speak at Everything Open. Possibly as a cross promotional effort.
Budgets for past events (Wellington and Canberra) will probably not be finalised until January.
Admin team update
Mainly working with Sae Ra on the test upgrade of the website. Have hit a few issues. Will need to reach out to AgileWare. Will probably require building a new VM once the actual software stack can be determined.
The admin team are also talking to FastMail to iron out the final details. In particular what LA offers to FastMail for their support. Possibly a pair of tickets to LA events per year. Subject to final approval by LA council.
Slack billing needs to be looked into, they appear to have a slightly odd billing cycle. Will probably be looking for a replacement for Slack or applying for a not-for-profit licence.
Joomla subcommittee update
Successfully running hybrid meetings
About time to have a face to face so the Joomla subcommittee is planning a mini Joomla day for 24 February. It will be a single day event.
Welcome on Friday night.
Program on Saturday.
Pizza/Code sprint on Sunday
It’s been three years since the last face to face event!
The goal is to keep the ticket price low.
Self fund drinks.
Not going to look for sponsors.
Bring your own T-shirt from previous conferences
Networking focussed event.
Rough budgets on 20/40/60 attendees.
Will also aim to hold Joomla committee elections.
Venue will be OPN 365’s office space.
PyCon AU subcommittee update
The PyCon AU team are unable to attend in person. Richard Jones has supplied this update:
Little has happened since the last update. Our focus has been on trying to secure a chair for the next conference, which is ongoing (but far from hopeless, we’re currently talking to a number of people).
Flounder subcommittee update
Recent meeting about SEL4, expect to have some more meetings on the topic in the future
Also have recently had meetings about Linux phones
Meetings tend to have about four attendees. Attendees vary with the topic.
Promoted via the Flounder website, matrix and email
Perhaps LA can help promote on other social media platforms (but it would be help if the council was reminded)
Ideal meeting size would be around 10 people. They tend to be focussed on technical work. If more attendees were present the focus could be shifted to more of a lecture style.
Following the successful first conference last year, this year’s 2023 International Conference on Green and Innovation-driven Development in Cities and Towns was hosted in Suzhou with proceedings held at the recently opened Suzhou International Conference Hotel. The lead host of the conference was the Foreign Affairs Office of the Jiangsu Provincial People’s Government, and the main organiser was the Xiangcheng District People’s Government of Suzhou City. Suzhou is a major city in east China, founded in 514 BCE and is now the most populous city in Jiangsu Province, with a population of roughly 7.5 million in the city and 14 million in the administrative area.
The conference theme was “Jointly creating a new platform for a new ecology for shared new benefits” which develops on President Xi Jinping’s statements on eco-civilization as embodied in the Chinese Constitution: “The construction of ecological civilization is a millennial plan for the sustainable development of the Chinese nation” of which the “two mountains theory”, i.e., “Green waters and green mountains are [as valuable as] mountains of gold and silver” (Lǜ shuǐ qīngshān
jiùshì jīnshān yín shān) also applies. With the world facing ever-increasing human-caused global warming that causes more extreme weather such an approach is necessary for both raising the income and wealth of people, as well as protecting and enhancing the welfare of all life on our shared planet.
Over 350 attendees were at the conference including Local and international dignitaries, academics, engineers, and scientists. International guests were from Japan, Malaysia, Vietnam, Portugal, Italy, New Zealand, and Australia. Following a welcoming banquet by Xiangcheng’s District People’s Government,
the formal proceedings included the opening ceremony followed by parallel sessions on towns with distinctive features, integrated development on urban and rural areas, and heritage protection with sustainable development. My own attendance was to the latter, which included a number of international and local speakers and case studies with examples from Italy, Portugal, the Netherlands, and Suzhou itself. There was, of course, an extensive comparison between Suzhou and Venice as two cities with extensive historical canals and other waterways.
The majority of the conference proceeding however was spent on visits to Suzhou, combining the two vectors of heritage conservation and environmental technologies. From the former, this included visits to the Imperial Kiln Bricks Museum, the Silk Museum, Embroidery Art Museum, the especially beautiful
Taihu Lake Wetland Park, and the UNESCO World Heritage site, the Humble Administrator’s Garden. For the latter, this included the Suzhou City Industrial Park Exhibition Centre, the Higer Bus Company, the High-Tech Zone Exhibition Hall, the Urban Planning Exhibition Hall (with its strong connections to Singapore), the High-Tech Rail Tram Limited, and the new local campus of Nanjing University, China’s most famous university.
The two vectors give credence to both the “two mountains theory” but also illustrate the genuine and successful attempt of Suzhou city and the region to integrate both heritage conservation, environmental protection, and technological development. It is difficult enough to achieve the former two, but when coupled with the latter great care and intelligence is required. The
development shown by Suzhou city illustrates the superficial contradiction between the “two mountains” can be resolved. One cannot help but be impressed by the dedication shown in the development of ICVs (Intelligent Connected Vehicles) and electric vehicles. The sheer quantity of electric cars
on the road is already apparent, and the numbers indicate that soon electric vehicles will make up the majority of new car sales in China, and the rest of the world will follow.
For international guests it must be mentioned with great appreciation that the hospitality shown by Foreign Affairs Office of the Jiangsu Provincial People’s Government was absolutely second to none. We were given a vision of a city that is prosperous, populous, harmonious, green, high-tech, planned, and showed a great sensitivity and appreciation of its history and culture. There is sensitivity to the fact that this was a relatively well-off city within China, and the city was very keen to promote itself on a local level in preference to discussing more regional, national, or even global environmental challenges. A desire was expressed by many to have greater detail and even an extra day in the proceedings that would discuss at a lower level various environmental and technological challenges. This is, of course, less of a criticism and more of a desire that attendees wanted the conference to be even longer and deeper.
If I may be so bold to finish on a personal note, often in the afternoons and evenings after the day’s proceedings I would take a walk around the lake and its environs that the hotel faced. Whilst there was the vista of the city with its gleaming towers of steel and glass, I would find myself among the foliage and fauna of the lakeside in a peaceful and contemplative setting. It was in this place that I could not help but be absolutely charmed by a solar-powered intelligent robot boat that would make its way over the lake, cleaning whatever rubbish it could find of which, of course, there was very little. What a different and beautiful world it would be, I thought to myself, it would be if such robots were everywhere. This is the vision of the future that is offered to us: “green and innovation-driven development in cities and towns”. It would do us all well, to look at this example.
Published in the Australia-China Friendship Society Victorian Branch Newsletter, November 2023
Way back in 2015 the University of Melbourne had a general-purpose high performance computer system called "Edward", which itself replaced an even smaller system called "Alfred", both named after the Kings of Wessex. Edward was a fairly typical machine for its vintage and, as is normal, when a system is being retired the main researchers were asked what should be different in the new system. What was also normal was their answers; more cores, faster CPUs, etc. Consideration was given to not having an HPC system at all, potentially offloading the demand to a national facility. But cooler heads that possibly understood network throughput and the advantages of fine-tuning a local system to the needs of local researchers prevailed.
One of the interesting things about the review of Edward's utilisation was how it differed from what many researchers thought they needed. Rather than a system with more cores etc, what was really needed was faster throughput. Researchers simply didn't like their jobs sitting in the queue. Coupled with the fact that finances to fund the system weren't great (the naming of Spartan was a laconic reference to its lean cost-efficiency), necessity became the mother of invention. The Nectar research cloud had plenty of cores and, according to the metrics, the overwhelming majority of Edward's jobs were being run for capacity, rather than capability; over 75% were single-core jobs and over 90% were single-node jobs. Rather than spend a lot of money on high-speed interconnect, which is typical in HPC systems, a decision was made to have a smaller traditional HPC partition ("physical") and use a partition virtual machines ("cloud") with a slow interconnect for those singe-node jobs.
It was an innovative design and received a well-deserved initial launch, followed by a world-tour explaining the architecture to various conferences and HPC centres, including Multicore World, Wellington, 2016, and 2017; eResearchAustralasia 2016, Center for Scientific Computing (CSC) Goethe University Frankfurt, 2016, High Performance Computing Center (HLRS) University of Stuttgart, 2016, High Performance Computing Centre Albert-Ludwigs-University Freiburg, 2016; European Organization for Nuclear Research (CERN), 2016, Centre Informatique National de l’Enseignement Supérieur, Montpellier, 2016; Centro Nacional de Supercomputación, Barcelona, 2016, and the OpenStack Summit, at Barcelona 2016, and featured in OpenStack and HPC Workload Management in Stig Telfer (ed), "The Crossroads of Cloud and HPC: OpenStack for Scientific Research" (Open Stack, 2016).
The success of Spartan's architecture soon became apparent. Whilst Edward had completed just over 375,000 jobs in 2015, Spartan completed more than a million in its first year from launch. The system expanded with additional compute nodes from specialist projects, departments, and research agencies that had purchased their own hardware. But the most significant expansion was the addition of a substantial GPGPU partition, of 68 nodes and 272 nVidia P100 GPGPU cards, funded by a Linkage Infrastructure, Equipment and Facilities (LIEF) grant. Later, Spartan also introduced FastX for interactive remote desktops, and interactive sessions through Open OnDemand for Jupyer notebooks, RStudio, and Cryosparc.
The introduction of the GPGPU partition really transformed Spartan. It was what changed Spartan from being a small, experimental, but extremely successful system, to a world-class computing system. At the time we estimated that it would have entered at c200 on the top500.org list. However, running the tests to enter into that celebrated list requires both a lot of fine-tuning and, of course, it means that users, which have priority on our system, won't be able to use the nodes. On Spartan, it is typical that 100% of workers nodes are fully allocated, so for literally years there was little opportunity for the tests to be conducted.
Recently however, Spartan finally took the leap to change from running RedHat 7.x, which we had been doing since 2015, gradually working our way up the point-released, to RedHat 9.x. This provided a well-advertised two-week window of opportunity and whilst many other changes occurred to the operating system, the hardware, and the recompilation of hundreds of applications, a work colleague, Naren Chinnam (with necessary coordination with the rest of the HPC, Network and DC teams in getting the cluster stable enough for the benchmarks to finish), completed the LINPACK test for part of the system. As a result, Spartan now has a nice certificate, rated at 454 in the world (and third in Australia, after NCI/Gadi and Pawsey), with a benchmark score of 2.14 PetaFlops, representing the performance of the GPU partitions alone. It has already been noted that we actually have 88 A100 GPU nodes, not the 72 that were tested, which would have brought us up to 337 in the world, plus another 1/3rd of our performance could have come from the CPU-only partitions.
At the time of writing, Spartan has run 53881908 HPC jobs. There are 6134 users from the University of Melbourne and around the world, across 2097 projects. The original architecture (with our friends at the University of Freiburg with their alternative cluster-cloud combination) was also featured at the IEEE 13th International Conference on e-Science in 2017, and in the Science, Technology and Engineering Systems Journal in 2019, with other presentations on Spartan including use of the GPGPU partition at eResearch 2018, its development path at eResearchAU 2020, interactive HPC at eResearchNZ 2021, and over 250 papers citing Spartan as a contributing factor their research. Spartan continues to grow in users, usage, performance and, most importantly, research outcomes. Spartan may have finally received its laurels, but we are not resting on them.
I use
reboot-notifier
on most of my
servers to let me
know when I need to reboot them for kernel updates since I want to decide
exactly when those machines go down. On the other hand, my home backup
server has very predictable usage patterns and so I decided to go one step
further there and automate these necessary reboots.
To do that, I first installed
reboot-notifier
which puts the following script in /etc/kernel/postinst.d/reboot-notifier
to detect when a new kernel was installed:
#!/bin/sh
if [ "$0" = "/etc/kernel/postinst.d/reboot-notifier" ]; then
DPKG_MAINTSCRIPT_PACKAGE=linux-base
fi
echo "*** System restart required ***" > /var/run/reboot-required
echo "$DPKG_MAINTSCRIPT_PACKAGE" >> /var/run/reboot-required.pkgs
Note that
unattended-upgrades
puts a similar script in /etc/kernel/postinst.d/unattended-upgrades:
#!/bin/sh
case "$DPKG_MAINTSCRIPT_PACKAGE::$DPKG_MAINTSCRIPT_NAME" in
linux-image-extra*::postrm)
exit 0;;
esac
if [ -d /var/run ]; then
touch /var/run/reboot-required
if ! grep -q "^$DPKG_MAINTSCRIPT_PACKAGE$" /var/run/reboot-required.pkgs 2> /dev/null ; then
echo "$DPKG_MAINTSCRIPT_PACKAGE" >> /var/run/reboot-required.pkgs
fi
fi
and so you only need one of them to be installed since they both write to
/var/run/reboot-required. It doesn't hurt to have both of them though.
Then I created the following cron job (/etc/cron.daily/reboot-local) to
actually reboot the server:
#!/bin/bash
REBOOT_REQUIRED=/var/run/reboot-required
if [ -s $REBOOT_REQUIRED ] ; then
cat "$REBOOT_REQUIRED" | /usr/bin/mail -s "Rebooting $HOSTNAME" root
/bin/systemctl reboot
fi
With that in place, my server will send me an email and then automatically
reboot itself.
This is a work in progress because I'd like to add some checks later on to
make sure that no backup is in progress during that time (maybe by looking
for active ssh connections?), but it works well enough for now. Feel free to
leave a comment if you've got a smarter script you'd like to share.
It’s time for a review of the second year of operation of our Redflow ZCell battery and Victron Energy inverter/charger system. To understand what follows it will help to read the earlier posts in this series:
Go With The Flow (what all the pieces are, what they do, some teething problems)
TANSTAAFL (review/analysis of the first year of operation)
In case ~12,000 words of background reading seem daunting, I’ll try to summarise the most important details here:
We have a 5.94kW solar array hooked up to a Victron MPPT RS solar charge controller, two Victron 5kW Multi-Plus II inverter/chargers, a Victron Cerbo GX console, and a single 10kWh Redflow ZCell battery. It works really well. We’re using most of our generated power locally, and it’s enabled us to blissfully coast through several grid power outages and various other minor glitches. The Victron gear and the ZCell were installed by Lifestyle Electrical Services.
Redflow batteries are excellent because you can 100% cycle them every day, and they aren’t a giant lump of lithium strapped to your house that’s impossible to put out if it bursts into flames. The catch is that they need to undergo periodic maintenance where they are completely discharged for a few hours at least every three days. If you have more than one, that’s fine because the maintenance cycles interleave (it’s all automatic). If you only have one, you can’t survive grid outages if you’re in a maintenance period, and you can’t ordinarily use the Cerbo’s Minimum State of Charge (MinSoC) setting to perpetually keep a small charge in the battery in case of emergencies. As we still only have one battery, I’ve spent a fair bit of time experimenting to mitigate this as much as I can.
The system itself requires a certain amount of power to run. Think of the pumps and fans in the battery, and the power used directly by the inverters and the console. On top of that a certain amount of power is simply lost to AC/DC conversion and charge/discharge inefficiencies. That’s power that comes into your house from the grid and from the sun that your loads, i.e. the things you care about running, don’t get to use. This is true of all solar PV and battery storage systems to a greater or lesser degree, but it’s not something that people always think about.
With the background out of the way we can get on to the fun stuff, including a roof replacement, an unexpected fault after a power outage followed by some mains switchboard rewiring, a small electrolyte leak, further hackery to keep a bit of charge in the battery most of the time, and finally some numbers.
The big job we did this year was replacing our concrete tile roof with colorbond steel. When we bought the house – which is in a rural area and thus a bushfire risk – we thought: “concrete brick exterior, concrete tile roof – sweet, that’s not flammable”. Unfortunately it turns out that while a tile roof works just fine to keep water out, it won’t keep embers out. There’s a gadzillion little gaps where the tiles overlap each other, and in an ember attack, embers will get up in there and ignite the fantastic amount of dust and other stuff that’s accumulated inside the ceiling over several decades, and then your house will burn down. This could be avoided by installing roof blanket insulation under the tiles, but in order to do that you have to first remove all the tiles and put them down somewhere without breaking them, then later put them all back on again. It’s a lot of work. Alternately, you can just rip them all off and replace the whole lot with nice new steel, with roof blanket insulation underneath.
Of course, you need good weather to replace a roof, and you need to take your solar panels down while it’s happening. This meant we had twenty-two solar panels stacked on our back porch for three weeks of prime PV time from February 17 – March 9, 2023, which I suspect lost us a good 500kW of power generation. Also, the roof job meant we didn’t have the budget to get a second ZCell this year – for the cost of the roof replacement, we could have had three new ZCells installed – but as my wife rightly pointed out, all the battery storage in the world won’t do you any good if your house burns down.
We had at least five grid power outages during the year. A few were brief, the grid being down for only a couple of minutes, but there were two longer ones in September (one for 30 minutes, one for about an hour and half). We got through the long ones just fine with either the sun high in the sky, or charge in the battery, or both. One of the earlier short outages though uncovered a problem. On the morning of May 30, my wife woke up to discover there was no power, and thus no running water. Not a good thing to wake up to. This happened while I was away, because of course something like this would happen while I was away. It turns out there had been a grid outage at about 02:10, then the grid power had come back, but our system had not. The Multis ended up in some sort of fault state and were refusing to power our loads. On the console was an alarm message: “#8 – Ground relay test failed”.
That doesn’t look good.
Note the times in the console messages are about 08:00. I confirmed via the logs from the VRM portal that the grid really did go out some time between 02:10 and 02:15, but after that there was nothing in the logs until 07:59, which is when my wife used the manual changeover switch to shift all our loads back to direct grid power, bypassing the Victron kit. That brought our internet connection back, along with the running water. I contacted Murray Roberts from Lifestyle Electrical and Simon Hackett for assistance, Murray logged in remotely and reset the Multis, my wife flicked the changeover switch back and everything was fine. But the question remained, what had gone wrong?
The ground relay in the Multis is there to connect neutral to ground when the grid fails. Neutral and ground are already physically connected on the grid (AC input) side of the Multis in the main switchboard, but when the grid power goes out, the Multis disconnect their inputs, which means the loads on the AC output side no longer have that fixed connection from neutral to ground. The ground relay activates in this case to provide that connection, which is necessary for correct operation of the safety switches on the power circuits in the house.
The ground relay is tested automatically by the Multis. Looking up Error 8 – Ground relay test failed on Victron’s web site indicated that either the ground relay really was faulty, or possibly there was a wiring fault or an issue with one of the loads in our house. So I did some testing. First, with the battery at 50% State of Charge (SoC), I did the following:
Disconnected all loads (i.e. flipped the breaker on the output side of the Multis)
Killed the mains (i.e. flipped the breaker on the input side of the Multis)
Verified the system switched to inverting mode (i.e. running off the battery)
Restored mains power
Verified there was no error
This demonstrated that the ground relay and the Multis in general were fine. Had there been a problem at that level we would have seen an error when I restored mains power. I then reconnected the loads and repeated steps 2-5 above. Again, there was no error which indicated the problem wasn’t due to a wiring defect or short in any of the power or lighting circuits. I also re-tested with the heater on and the water pump running just in case there may have been an issue specifically with either of those devices. Again, there was no error.
The only difference between my test above and the power outage in the middle of the night was that in the middle of the night there was no charge in the battery (it was right after a maintenance cycle) and no power from the sun. So in the evening I turned off the DC isolators for the PV and deactivated my overnight scheduled grid charge so there’d be no backup power of any form in the morning. Then I repeated the test:
Disconnected all loads
Killed the mains.
Checked the console which showed the system as “off”, as opposed to “inverting”, as there was no battery power or solar generation
Restored mains power
Shortly thereafter, I got the ground relay test failed error
The underlying detailed error message was “PE2 Closed”, which meant that it was seeing the relay as closed when it’s meant to be open. Our best guess is that we’d somehow hit an edge case in the Multi’s ground relay test, where they maybe tried to switch to inverting mode and activated the ground relay, then just died in that state because there was no backup power, and got confused when mains power returned. I got things running again by simply power cycling the Multis.
So it kinda wasn’t a big deal, except that if the grid went out briefly with no backup power, our loads would remain without power until one of us manually reset the system. This was arguably worse than not having the system at all, especially if it happened in the middle of the night, or when we were away from home. The fact that we didn’t hit this problem in the first year of operation is a testament to how unlikely this event is, but the fact that it could happen at all remained a problem.
One fix would have been to get a second battery, because then we’d be able to keep at least a tiny bit of backup power at all times regardless of maintenance cycles, but we’re not there yet. Happily, Simon found another fix, which was to physically connect the neutral together between the AC input and AC output sides of the Multis, then reconfigure them to use the grid code “AS4777.2:2015 AC Neutral Path externally joined”. That physical link means the load (output) side picks up the ground connection from the grid (input) side in the swichboard, and changing the grid code setting in the Multis disables the ground relay and thus the test which isn’t necessary anymore.
Murray needed to come out anyway to replace the carbon sock in the ZCell (a small item of annual maintenance) and was able to do that little bit of rewriting and configuration at the same time. I repeated my tests both with and without backup power and everything worked perfectly, i.e. the system came back immediately by itself after a grid outage with no backup power, and of course switched over to inverting just fine when there was backup power available.
This leads to the next little bit of fun. The carbon sock is a thing that sits inside the zinc electrolyte tank and helps to keep the electrolyte pH in the correct operating range. Unfortunately I didn’t manage to get a photo of one, but they look a bit like door snakes. Replacing the carbon sock means opening the case, popping one side of the Gas Handling Unit (GHU) off the tank, pulling out the old sock and putting in a new one. Here’s a picture of the ZCell with the back of the case off, indicating where the carbon sock goes:
The tank on the left (with the cooling fan) is for zinc electrolyte. The tank on the right is for bromine electrolyte. The blocky assembly of pipes going into both tanks is the GHU. The rectangular box behind that contains the electrode stacks.
When Murray popped the GHU off, he noticed that one of the larger pipes on one side had perished slightly. Thankfully he happened to have a spare GHU with him so was able to replace the assembly immediately. All was well until later that afternoon, when the battery indicated hardware failure due to “Leak 1 Trip” and shut itself down out of an abundance of caution. Upon further investigation the next day, Murry and I discovered there was a tiny split in one of the little hoses going into the GHU which was letting the electrolyte drip out.
Drip… Drip… Drip…
This small electrolyte leak was caught lower down in the battery, where the leak sensor is. Murray sucked the leaked electrolyte out of there, re-terminated that little hose and we were back in business. I was happy to learn that Redflow had obviously thought about the possibility of this type of failure and handled it. As I said to Murray at the time, we’d rather have a battery that leaks then turns itself off than a battery that catches fire!
Aside from those two interesting events, the rest of the year of operation was largely quite boring, which is exactly what one wants from a power system. As before I kept a small overnight scheduled charge and a larger late afternoon scheduled charge active on weekdays to ensure there was some power in the battery to use at peak (i.e. expensive) grid times. In spring and summer the afternoon charge is largely superfluous because the battery has usually been well filled up from the solar by then anyway, but there’s no harm in leaving it turned on. The one hack I did do during the year was to figure out a way to keep a small (I went with 15%) MinSoC in the battery at all times except for maintenance cycle evenings, and the morning after. This is more than enough to smooth out minor grid outages of a few minutes, and given our general load levels should be enough to run the house for more than an hour overnight if necessary, provided the hot water system and heating don’t decide to come on at the same time.
My earlier experiment along these lines involved a script that ran on the Cerbo twice a day to adjust scheduled charge settings in order to keep the battery at 100% SoC at all times except for peak electricity hours and maintenance cycle evenings. As mentioned in TANSTAAFL I ran that for all of July, August and most of September 2022. It worked fine, but ultimately I decided it was largely a waste of energy and money, especially when run during the winter months when there’s not much sun and you end up doing a lot of grid charging. This is a horribly inefficient way of getting power into the battery (AC to DC) versus charging the battery direct from solar PV. We did still use those scripts in the second year, but rather more judiciously, i.e. we kept an eye on the BOM forecasts as we always do, then occasionally activated the 100% charge when we knew severe weather and/or thunderstorms were on the way, those being the things most likely to cause extended grid outages. I also manually triggered maintenance on the battery earlier than strictly necessary several times when we expected severe weather in the coming days, to avoid having a maintenance cycle (and thus empty battery) coincide with potential outages. On most of those occasions this effort proved to be unnecessary. Bearing all that in mind, my general advice to anyone else with a single ZCell system (aside from maybe adding scheduled charges to time-shift expensive peak electricity) is to just leave it alone and let it do its thing. You’ll use most of your locally generated electricity onsite, you’ll save some money on your power bills, and you’ll avoid some, but not all, grid outages. This is a pretty good position to be in.
That said, I couldn’t resist messing around some more, hence my MinSoC experiment. Simon’s installation guide points out that “for correct system operation, the Settings->ESS menu ‘Min SoC’ value must be set to 0% in single-ZCell systems”. The issue here is that if MinSoC is greater than 0%, the Victron gear will try to charge the battery while the battery is simultaneously trying to empty itself during maintenance, which of course just isn’t going to work. My solution to this is the following script, which I run from a cron job on the Cerbo twice a day, once at midnight UTC and again at 06:00 UTC with the --check-maintenance flag set:
Midnight UTC corresponds to the end of our morning peak electricity time, and 06:00 UTC corresponds to the start of our afternoon peak. What this means is that after the morning peak finishes, the MinSoC setting will cause the system to automatically charge the battery to the value specified if it’s not up there already. Given it’s after the morning peak (10:00 AEST / 11:00 AEDT) this charge will likely come from solar PV, not the grid. When the script runs again just before the afternoon peak (16:00 AEST / 17:00 AEDT), MinSoC is set to either the value specified (effectively a no-op), or zero if it’s a maintenance day. This allows the battery to be discharged correctly in the evening on maintenance days, while keeping some charge every other day in case of emergencies. Unlike the script that tries for 100% SoC, this arrangement results in far less grid charging, while still giving protection from minor outages most of the time.
In case Simon is reading this now and is thinking “FFS, I wrote ‘MinSoC must be set to 0% in single-ZCell systems’ for a reason!” I should also add a note of caution. The script above detects ZCell maintenance cycles based solely on the configured maintenance time limit and the duration since last maintenance. It does not – and cannot – take into account occasions when the user manually forces maintenance, or situations in which a ZCell for whatever reason hypothetically decides to go into maintenance of its own accord. The latter shouldn’t generally happen, but it can. The point is, if you’re running this MinSoC script from a cron job, you really do still want to keep an eye on what the battery is doing each day, in case you need to turn that setting off and disable the cron job. If you’re not up for that I will reiterate my general advice from earlier: just leave the system alone – let it do its thing and you’ll (almost always) be perfectly fine. Or, get a second ZCell and you can ignore the last several paragraphs entirely.
Now, finally, let’s look at some numbers. The year periods here are a little sloppy for irritating historical reasons. 2018-2019, 2019-2020 and 2020-2021 are all August-based due to Aurora Energy’s previous quarterly billing cycle. The 2021-2022 year starts in late September partly because I had to wait until our new electricity meter was installed in September 2021, and partly because it let me include some nice screenshots when I started writing TANSTAAFL on September 25, 2022. I’ve chosen to make this year (2022-2023) mostly sane, in that it runs from October 1, 2022 through September 30, 2023 inclusive. This is only six days offset from the previous year, but notably makes it much easier to accurately correlate data from the VRM portal with our bills from Aurora. Overall we have five consecutive non-overlapping 12 month periods that are pretty close together. It’s not perfect, but I think it’s good enough to work with for our purposes here.
YeaR
Grid In
Solar In
Total In
Loads
Export
2018-2019
9,031
6,682
15,713
11,827
3,886
2019-2020
9,324
6,468
15,792
12,255
3,537
2020-2021
7,582
6,347
13,929
10,358
3,571
2021-2022
8,531
5,640
14,171
10,849
754
2022-2023
8,936
5,744
14,680
11,534
799
Overall, 2022-2023 had a similar shape to 2021-2022, including the fact that in both these years we missed three weeks of solar generation in late summer. In 2022 this was due to replacing the MPPT, and in 2023 it was because we replaced the roof. In both cases our PV generation was lower than it should have been by an estimated 500-600kW. Hopefully nothing like this happens again in future years.
All of our numbers in 2022-2023 were a bit higher than in 2021-2022. We pulled 4.75% more power from the grid, generated 1.84% more solar, the total power going into the system (grid + solar) was 3.59% higher, our loads used 6.31% more power, and we exported 5.97% more power than the previous year.
I honestly don’t know why our loads used more power this year. Here’s a table showing our consumption for both years, and the differences each month (note that September 2022 is only approximate because of how the years don’t quite line up):
Month
2022
2023
Diff
October
988
873
-115
November
866
805
-61
December
767
965
198
January
822
775
-47
February
638
721
83
March
813
911
98
April
775
1,115
340
May
953
1,098
145
June
1,073
1,149
76
July
1,118
1,103
-15
August
966
1,065
99
September
1,070
964
-116
Here’s a graph:
WTF happened in December and April?!?
Did we use more cooling this December? Did we use more heating this April and May? I dug the nearest weather station’s monthly mean minimum and maximum temperatures out of the BOM Climate Data Online tool and found that there’s maybe a degree or so variance one way or the other each month year to year, so I don’t know what I can infer from that. All I can say is that something happened in December and April, but I don’t know what.
Another interesting thing is that what I referred to as “the energy cost of the system” in TANSTAAFL has gone down. That’s the kW figure below in the “what?” column, which is the difference between grid in + solar in – loads – export, i.e. the power consumed by the system itself. In 2021-2022, that was 2,568 kW, or about 18% of the total power than went into the system. In 2022-2023 it was only 1,838kWh, or 12.5%:
Year
Grid In
Solar In
Total In
Loads
Export
Total Out
what?
2021-2022
8,531
5,640
14,171
10,849
754
11,603
2,568
2022-2023
8,963
5,744
14,680
11,534
799
12,333
1,838
The cause of this reduction is almost certainly that we didn’t spend two and a half months doing lots of grid charging of the battery in 2022-2023. This again points to the advisability of just letting the system do its thing and not messing with it too much unless you really know you need to.
The last set of numbers I have involve actual money. Here’s what our electricity bills looked like over the past five years:
Year
From Grid
Total Bill
Cost/kWh
2018-2019
9,031
$2,278.33
$0.25
2019-2020
9,324
$2,384.79
$0.26
2020-2021
7,582
$1,921.77
$0.25
2021-2022
8,531
$1,731.40
$0.20
2022-2023
8,936
$1,989.12
$0.22
Note that cost/kWh as I have it here is simply the total dollar amount of our bills divided by the total power drawn from the grid (I’m deliberately ignoring the additional power we use that comes from the sun in this calculation). The bills themselves say “peak power costs $X, off-peak costs $Y, you get $Z back for power exported and there’s a daily supply charge of $SUCKS_TO_BE_YOU”, but that’s all noise. What ultimately matters in my opinion is what I call the effective cost per kilowatt hour, which is why those things are all smooshed together here. The important point is that with our existing solar array we were previously effectively paying about $0.25 per kWh for grid power. After getting the battery and switching to Peak & Off-Peak billing, that went down to $0.20/kWh – a reduction of 20%. Now we’ve inched back up to $0.22/kWh, but it turns out that’s just because power prices have increased. As far as I can tell Aurora Energy don’t publish historical pricing data, so as a public service, I’ll include what I’ve been able to glean from our prior bills here:
July 2023 onwards:
Daily supply charge: $1.26389
Peak: $0.36198/kWh
Off-Peak: $0.16855/kWh
Feed-In Tariff: $0.10869/kWh
July 2022 – July 2023
Daily supply charge: $1.09903
Peak: $0.33399/kWh
Off-Peak: $0.15551/kWh
Feed-In Tariff: $0.08883/kWh
Before July 2022:
Daily supply charge: $0.98
Peak: $0.29852
Off-Peak: $0.139
Feed-In Tariff: $0.06501
It’s nice that the feed-in tariff (i.e. what you get credited when you export power) has gone up quite a bit, but unless you’re somehow able to export 2-3x more power than you import, you’ll never get ahead of the ~20% increase in power prices over the last two years.
Having calculated the effective cost/kWh for grid power, I’m now going to do one more thing which I didn’t think to do during last year’s analysis, and that’s calculate the effective cost/kWh of running our loads, bearing in mind that they’re partially powered from the grid, and partially from the sun. I’ve managed to dig up some old Aurora bills from 2016-2017, back before we put the solar panels on. This should make for an interesting comparison.
Year
From Grid
Total Bill
Grid $/kWh
Loads
Loads $/kWh
2016-2017
17,026
$4,485.45
$0.26
17,026
$0.26
2018-2019
9,031
$2,278.33
$0.25
11,827
$0.19
2019-2020
9,324
$2,384.79
$0.26
12,255
$0.19
2020-2021
7,582
$1,921.77
$0.25
10,358
$0.19
2021-2022
8,531
$1,731.40
$0.20
10,849
$0.16
2022-2023
8,936
$1,989.12
$0.22
11,534
$0.17
The first thing to note is the horrifying 17 megawatts we pulled in 2016-2017. Given the hot water and lounge room heat pump were on a separate tariff, I was able to determine that four of those megawatts (i.e. about 24% of our power usage) went on heating that year. Replacing the crusty old conventional electric hot water system with a Sanden heat pump hot water service cut that in half – subsequent years showed the heating/hot water tariff using about 2MW/year. We obviously also somehow reduced our loads by another ~3MW/year on top of that, but I can’t find the Aurora bills for 2017-2018 so I’m not sure exactly when that drop happened. My best guess is that I probably got rid of some old, always-on computer equipment.
The second thing to note is how the cost of running the loads drops. In 2016-2017 the grid cost/kWh is the same as the loads cost/kWh, because grid power is all we had. From 2018-2021 though, the load cost/kWh drops to $0.19, a saving of about 26%. It remains there until 2021-2022 when we got the battery and it dropped again to $0.16 (another 15% or so). So the big win was certainly putting the solar panels on and swapping the hot water system, with the battery being a decent improvement on top of that.
Further wins are going to come from decreasing our power consumption. In previous posts I had mentioned the need to replace panel heaters with heat pumps, and also that some of our aging computer equipment needed upgrading. We did finally get a heat pump installed in the master bedroom this year, and we replaced the old undersized lounge room heat pump with a new correctly sized unit. This happened on June 30 though, so will have had minimal impact on this years’ figures. Likewise an always-on computer that previously pulled ~100W is now better, stronger and faster in all respects, while only pulling ~50W. That will save us ~438kW of power per year, but given the upgrade happened in mid August, again we won’t see the full effects until later.
I’m looking forward to doing another one of these posts in a year’s time. Hopefully I will have nothing at all interesting to report.
As an OpenBSD package maintainer, I often need to watch for updates on packages I maintain. I used to do this using repology.org, which has the benefit of tracking package updates in many distros, but it can be unreliable for OpenBSD packages due to network delay and parsing problems.
One better way to watch for upstream update is using OpenBSD’s portroach service, it monitors new upstream release and provides a JSON API that can be combined with jq(1) to produce clear information.
To find all packages that can be updated for a given maintainer, first find the maintainer page on portroach, you can search by maintainer name and the page’s URL should be similar to the following:
This endpoint will return all the packages maintained by a given maintainer, regardless of having an update or not. To only show packaged that can be updated, jq(1) can be used as a powerful filter and formatter:
Please be mindful that portroach is not infaillible, it may produce inaccurate result for some upstreams. The hosted version is a community resource, so please don’t abuse it, If you want, you can selfhost it with source code from its GitHub repository.
A few weeks ago, I upgraded a few machines from Ubuntu 20.04 (focal) to
22.04 (jammy). Here are the things that needed fixing after the upgrade.
Network problems
Firstly, I had to fix the resolution of .local domains the same
way
as I did when I upgraded a different machine from 18.04 (bionic) to 20.04
(focal).
ssh agent problems
Then, I found that ssh-add no longer worked and instead returned this error:
Could not open connection to your authentication agent
While this appears to be a known
issue, the
work-around suggested in the i3
forum didn't work for me. What
did work was the solution described in this blog
post:
I'm not sure why ED25519 keys don't work in gnome-keyring since that
bug was supposedly fixed
a while back, but starting gnome-keyring-ssh.service instead of
ssh-agent.service didn't work for me.
Packages
When it comes to specific packages, I removed this obsolete package:
As always, I put any packages I backport from Debian unstable into my
PPA.
So far with jammy, I only had to update
tiger to silence some bogus warnings.
At this point, all of the traffic from that browser should be flowing
through your mitmproxy instance.
Android setup
On Android, it's a little less straightforward:
Start mitmproxy on your desktop:
mitmproxy --mode regular --listen-port 9000
Open that port on your desktop firewall if needed.
On your Android device, change your WiFi settings for the current access point:
Proxy: Manual
Proxy hostname: 192.168.1.100 (IP address of your desktop)
Proxy port: 9000
Turn off any VPN.
Turn off WiFi.
Turn WiFi back on.
Open http://mitm.it in a browser to download the certificate authority file.
Open the system Settings, Security and privacy, More security and
privacy, Encryption & credentials, Install a certificate and finally
choose CA certificate.
Tap Install anyway to dismiss the warning and select the file you just downloaded.
Once you have gone through all of these steps, you should be able to monitor
(on your desktop) the HTTP and HTTPS requests made inside of your Android
browsers.
git-annex(1) is a versatile and cross-platform tool build on top of git, it can sync, backup, archive files and provides many useful primitives for building customized workflow and storage system, for example, by combining git-annex with gcrypt, it’s possible to fully encrypt data stored on a remote.
Partially due to its versatility, it has a steeper learning curve than some other tools in this field and it took me some time to figure out how to make it work for me, here is a quick guide that documents my journey.
git-annex supports multiple encryption mode, I will be going with the default hybrid mode since it allows more keys to be added in future. In this mode, data is encrypted with gpg using a symmetric key generated during remote initialization, the key then is encrypted by a gpg public key specified during initremote. After that, the symmetric key is checked into the git repository. This is useful when multiple users wish to access the same encrypted repository, but doing so is outside the scope of this post, for doing that and other advanced operations, read git-annex’s gcrypt guide for more details.
I opt to create a new key for this use case, but any gpg key will do.
To accecss this encrypted repository from another machine (e.g. a desktop PC), first setup the gpg key on such machine, then clone and decrypt the repository:
desktop$ git clone gcrypt::rsync://server_hostname/path/to/myrepo-remote myrepo
Cloning into 'myrepo'...
gcrypt: Decrypting manifest
gpg: Good signature from "omnirepo (annex)" [unknown]
gcrypt: Remote ID is :id:XXX
Receiving objects: 100% (5/5), done.
Sync command will also work on the new machine for sending modified files to the remote:
With the two big PRs introducing our next generation of asset support merged (here and here), September was a month for rapid iteration and working towards getting assets out in a 2.1 beta release.
The pace was lively! Towards the end of the month, Luca and I were trading PRs and code reviews on almost a daily basis. Thanks our opposing timezones, Hanami was being written nearly 24h a day!
There was one interesting piece though. Earlier in this release cycle (back in June!), I overhauled our user-facing error handling. I added a middleware to catch errors and render static error pages intended display in production. As part of this change, I adjusted our router to raise exceptions for not found routes: doing this would allow the error to be caught and a proper 404 page displayed. So that was production sorted. For development, we integrated the venerable better_errors, wrapped by our own hanami-webconsole gem.
It was only some months later that we realised 404s in development were being returned as 500s. This turned out to be because better_errors defaults to a 500 response code at all times. In its middleware:
Well, maybe not quite at all times. The lines right beneath status_code = 500:
status_code = 500
if defined?(ActionDispatch::ExceptionWrapper) && exception
status_code = ActionDispatch::ExceptionWrapper.new(env, exception).status_code
end
Looks like Ruby on Rails gets its own little exception carved out here, via some hard-coded constant checks that reach deep inside Rails internals. This will allow better_errors to return a 404 for a not found error in Rails, but not in any other Ruby framework.
This is not a new change. It arrived over ten years ago, and I can hardly blame the authors for wanting a way to make this work nicely with the predominant Ruby application framework of the day.
Today, however, is a different day! We’re here to change the Ruby framework balance. � So we needed a way to make this work for Hanami. What didn’t feel feasible at this point was a significant change to better_errors: our time was limited and at best we had the appetite only for a minor tactical fix.
module BetterErrorsExtension
# The BetterErrors middleware always returns a 500 status when rescuing an exception
# (outside of Rails). This is not not always appropriate, such as for a
# `Hanami::Router::NotFoundError`, which should be a 404.
#
# To account for this, gently patch `BetterErrors::Middleware#show_error_page` (which is
# called only when an exception has been rescued) to pass that rescued exception to a proc
# we inject into the rack env here in our own middleware. This allows our middleware to know
# the about exception class and provide the correct status code after BetterErrors is done
# with its job.
#
# @see Webconsole::Middleware#call
def show_error_page(env, exception = nil)
if (capture_proc = env[CAPTURE_EXCEPTION_PROC_KEY])
capture_proc.call(exception)
end
super
end
end
BetterErrors::Middleware.prepend(BetterErrorsExtension)
In order to know which response code to use for the page, we need access to the exception that better_error is catching. Right now it provides no hooks to expose that. So instead we prepend some behaviour in front of their #show_error_page, which is only called by the time an error is to be rendered. We look for a proc on the rack env, and if one is there, we pass the exception to it, and then let better_errors get on with the rest of its normal work.
Then, in our own webconsole middleware, we set that proc to capture the exception, using Ruby closure semantics to assign that exception directly to a local variable:
def call(env)
rescued_exception = nil
env[CAPTURE_EXCEPTION_PROC_KEY] = -> ex { rescued_exception = ex }
# ...
end
After that, we call the better_errors middleware, letting it do its own thing:
def call(env)
rescued_exception = nil
env[CAPTURE_EXCEPTION_PROC_KEY] = -> ex { rescued_exception = ex }
status, headers, body = @better_errors.call(env)
end
And then once that is done, we can use the exception (if we have one) to fetch an appropriate response code from the Hanami app config, and then override better_errors’ response code with our own:
def call(env)
rescued_exception = nil
env[CAPTURE_EXCEPTION_PROC_KEY] = -> ex { rescued_exception = ex }
status, headers, body = @better_errors.call(env)
# Replace the BetterErrors status with a properly configured one for the Hanami app
if rescued_exception
status = Rack::Utils.status_code(
@config.render_error_responses[rescued_exception.class.name]
)
end
[status, headers, body]
end
That’s it! Given how light touch this is, and how stable better_errors is, I’m confident this will serve our purposes quite well for now.
We don’t want to live with this forever, however. In our future I see a fit for purpose developer errors reporter that is fully integrated with Hanami’s developer experience. Given current timelines, this will probably won’t come for at least 12 months, so if this is something you’re interested in helping with, please reach out!
Kickstarting dry-operation!
While the work on Hanami continued, I also helped kickstart work on a new dry-rb gem: dry-operation! Serving as the successor to dry-transaction, with dry-operation we’ll introduce significant new flexibility to modelling composable business operations, while still keeping a high-level API that presents their key flows in an easy to follow way.
I’m excited we’re finally providing a bridge to the future for dry-transaction, and at the same time building one of the final pieces of the puzzle for full stack Hanami apps. This is an interesting one for me personally, too, since I’m acting more as a “product manager� for this effort, with Marc doing most of the direct development work. Marc’s been in the dry-rb/Hanami orbit for a while now, and I’m excited for this opportunity for him to step up his contributions. More on this in the future!
Releasing Hanami 2.1.0.beta2!
After all of this, we capped the month off with the release of Hanami 2.1.0.beta2! This was a big step: our first beta to include both views and assets together. In the time since this release we’ve already learnt a ton and found way to take things to another level… but more on that next month. 😉 See you then!
and then adding apparmor=1 security=apparmor to the kernel command line
(GRUB_CMDLINE_LINUX) in /etc/default/grub.
Move away from using Linode's kernels
As mentioned in this blog
post, I found out that
these parameters are ignored by the Linode kernels.
I had to:
login to the Linode Manager (i.e.
https://cloud.linode.com/linodes/<linode ID>/configurations),
click the node relevant node,
click "Edit" next to the configuration profile, and
change the kernel to "GRUB 2".
Fix grub
Next I found out that grub doesn't actually install itself properly because
it can't be installed directly on the virtual drives provided by Linode
(KVM). Manually running this
hack
worked for me:
grub-install --grub-setup=/bin/true /dev/null
Unbound + Let's Encrypt fix
Finally, my local Unbound
installation stopped
working because it couldn't access the Let's Encrypt certificates anymore.
The solution to this was pretty
straightforward. All I needed to do was to add the following to
/etc/apparmor.d/local/usr.sbin.unbound:
This post is about AmigaOS 3.1.4 on my Amiga 2000. AmigaOS 3.1 from Amiga works fine. However, there are a few interestingly subtle differences between 3.1 and 3.1.4 that are worth knowing about, and they stem from both OS and ROM changes that you need to be aware of.
Let's start with why I reinstalled it.
I did it a few months ago and didn't notice that I had only allocated a 10 megabyte OS partition. Oops. So, I figured I'd install it again before I started doing more work on it, and I remembered the hilarity from last time. This time, though, I took more photos to demonstrate it.
First up, the Amiga 2000. It has the 3.1 ROM from Amiga Forever. I think it doesn't include workbench.library and icons.library in the ROM due to size restrictions. So, you need to have that installed onto your boot media. AmigaOS 3.1.4 does that for you. If you use 3.1 ROMs with earlier installs of AmigaOS then you need to grab those libraries and put them in your SYS: folder yourself.
So, yes I bought some.
Then, the install disk. I have a TF536 in here and 8MB of Zorro-II RAM, hence the large amount of RAM.
Anyway, I started off by re-partitioning the drive using the HDToolBox program. It's supplied on the installation disk. Now, the 3.1.4 ROM includes a scsi.device that works with Amiga 600 style IDE, so I don't need any extra stuff to use the CF adapter on the TF536.
Oops. My boot partition is too small. Let's delete and reinitialise this.
Ok, that's better. Let's save and reboot.
Next - we reboot and reinitialise the disks with a fast format. Here's workbench:
Easy. Now, we run the installer. And, we select "Intermediary" install - or it won't correctly the detect the machine I am installing on, and thus won't install the right version of libraries that are no longer on the 3.1.4 ROM.
And now we begin.
Now after a bunch of disk swaps, it'll ask which version of hardware you have.
The first time I did this on the Amiga 2000 I did the Novice install and it asked for my Amiga 600 disks. Well, obviously I didn't have an Amiga 600. But when I bought the disks I didn't have the modules disks either! I had to sleuth around on the internet to find them. So now I have them for my Amiga 500/1000, 1200 and 2000.
Anyway, it goes and installs the extra bits and pieces.
Finally it's done and I am told that I have a 32 bit CPU (which I do) and I need to do some extra work after reboot (which I will.)
I reboot, and here we are, basic install done. I'm warned again that I should go and install the CPU support stuff.
That's it for now. Next time (if I remember) I'll take photos of installing the CPU support toolkit, the network interface driver and then run AmigaTestKit and SysInfo to show it all together. Then after that it'll be reinstalling the network stack, and then on to music editing stuff.
The expression "Not all members of set N have characteristic r, but all elements with characteristic r are in set N" can be represented with standard set notation as follows.
1. There exist some elements in N that do not have characteristic r. Using the "∃" symbol, to denote "there exists", and the "∉" symbol, which denotes "not an element of."
∃x ∈ N : x ∉ R
This reads as "There exists an element x in N such that x is not an element of R."
2. For the second part, all elements with characteristic r are in set N:
This means that every element in set R is also in set N. This can be represented using the subset symbol "⊆."
R ⊆ N
This reads as "R is a subset of N," meaning every element in R is also an element in N.
3. So, combining both statements:
∃x ∈ N : x ∉ R and R ⊆ N
This expresses that not all members of set N ("No voters") have characteristic r ("racism"), but all elements with characteristic r ("racism") are in set N ("No voters").
Not all "no" voters are racist, but all racists are "no" voters.
August turned out to bring a lot of forward motion for our work on Hanami’s front end assets support. While Luca was taking his summer break, I carried on his work preparing hanami-assets 2.1 and its integration into the Hanami framework. Last week we caught up for a quick chat about these, and now both are merged!
Personally, I think this was an exciting evolution of how Luca and I work together. While previously we each took care of fairly distinct lines of work (there was enough to do, after all!), here we literally worked in tandem on one specific area, and it came out great!
Luca and I also hopped on another video call during August, this time with Seb Wilgosz of Hanami Mastery to record a special core team interview for the site’s 50th episode! I really enjoyed the chance to answer community questions about Hanami, and personally, it was a moment of reassurance that we’re still on the right track and are delivering useful things to people.
The episode isn’t published yet, but one thing that did arise from the episode is a new Hanami 2.1 GitHub project that I put together for tracking our remaining work for the release. Previously, this was in Trello, and with the move to GitHub I hope it will make not our remaining work move visible, but also create clearer opportunities for potential contributors.
Now, with those big two PRs merged and our remaining work more clearly listed, the pace is picking up! We’re now at the point where we can focus on the direct user experience of working with assets within a full Hanami app. I expect a lot will shake out from this in quick order. But more on that next month!
I (relatively) recently went down the rabbit hole of trying out personal finance apps to help get a better grip on, well, the things you’d expect (personal finances and planning around them).
In the past, I’ve had an off-again-on-again relationship with GNUCash. I did give it a solid go for a few months in 2004/2005 it seems (I found my old files) and I even had the OFX exports of transactions for a limited amount of time for a limited number of bank accounts! Amazingly, there’s a GNUCash port to macOS, and it’ll happily open up this file from what is alarmingly close to 20 years ago.
Back in those times, running Linux on the desktop was even more of an adventure than it has been since then, and I always found GNUCash to be strange (possibly a theme with me and personal finance software), but generally fine. It doesn’t seem to have changed a great deal in the years since. You still have to manually import data from your bank unless you happen to be lucky enough to live in the very limited number of places where there’s some kind of automation for it.
So, going back to GNUCash was an option. But I wanted to survey the land of what was available, and if it was possible to exchange money for convenience. I am not big on the motivation to go and spend a lot of time on this kind of thing anyway, so it had to be easy for me to do so.
For my requirements, I basically had:
Support multiple currencies
Be able to import data from my banks, even if manually
Some kind of reporting and planning tools
Be easy enough to use for me, and not leave me struggling with unknown concepts
The ability to export data. No vendor lock-in
I viewed a mobile app (iOS) as a Nice to Have rather than essential. Given that, my shortlist was:
I’ve used it before, its web site at https://www.gnucash.org/ looks much the same as it always has. It’s Free and Open Source Software, and is thus well aligned with my values, and that’s a big step towards not having vendor lock-in.
I honestly could probably make it work. I wish it had the ability to import transactions from banks for anywhere I have ever lived or banked with. I also wish the UI got to be a bit more consistent and modern, and even remotely Mac like on the Mac version.
Honestly, if the deal was that a web service would pull bank transactions in exchange for ~$10/month and also fund GNUCash development… I’d struggle to say no.
Here’s an option that has been around forever – https://www.quicken.com/ – and one that I figured I should solidly look at. It’s actually one I even spent money on…. before requesting a refund. It’s Import/Export is so broken it’s an insult to broken software everywhere.
Did you know that Quicken doesn’t import the Quicken Interchange Format (QIF), and hasn’t since 2005?
Me, incredulously, when trying out quicken
I don’t understand why you wouldn’t support as many as possible formats that banks export your transaction data as. It cannot possibly be that hard to parse these things, nor can it possibly be code that requires a lot of maintenance.
This basically meant that I couldn’t import data from my Australian Banks. Urgh. This alone ruled it out.
It really didn’t build confidence in ever getting my data out. At every turn it seemed to be really keen on locking you into Quicken rather than having a good experience all-up.
This one was new to me – https://www.wiz.money/ – and had a fancy URL and everything. I spent a bunch of time trying MoneyWiz, and I concluded that it is pretty, but buggy. I had managed to create a report where it said I’d earned $0, but you click into it, and then it gives actual numbers. Not being self consistent and getting the numbers wrong, when this is literally the only function of said app (to get the numbers right), took this out of the running.
It did sync from my US and Australian banks though, so points there.
Intuit used to own Quicken until it sold it to H.I.G. Capital in 2016 (according to Wikipedia). I have no idea if that has had an impact as to the feature set / usability of Quicken, but they now have this Cloud-only product called Mint.
The big issue I had with Mint was that there didn’t seem to be any way to get your data out of it. It seemed to exemplify vendor lock-in. This seems to have changed a bit since I was originally looking, which is good (maybe I just couldn’t find it?). But with the cloud-only approach I wasn’t hugely comfortable with having everything there. It also seemed to be lacking a few features that I was begging to find useful in other places.
It is the only product that links with the Apple Card though. No idea why that is the case.
The price tag of $0 was pretty unbeatable, which does make me wonder where the money is made from to fund its development and maintenance. My guess is that it’s through commission on the various financial products advertised through it, and I dearly hope it is not through selling data on its users (I have no reason to believe it is, there’s just the popular habit of companies doing this).
This is what I’ve settled on. It seemed to be easy enough for me to figure out how to use, sync with an iPhone App, be a reasonable price, and be able to import and sync things from accounts that I have. Oddly enough, nothing can connect and pull things from the Apple Card – which is really weird. That isn’t a Banktivity thing though, that’s just universal (except for Intuit’s Mint).
I’ve been using it for a bit more than a year now, and am still pretty happy. I wish there was the ability to attach a PDF of a statement to the Statement that you reconcile. I wish I could better tune the auto match/classification rules, and a few other relatively minor things.
Periodically in life I’ve had the desire to be somewhat fit, or at least have the benefits that come with that such as not dying early and being able to navigate a mountain (or just the city of Seattle) on foot without collapsing. I have also found that holding myself accountable via data is pretty vital to me actually going and repeatedly doing something.
So, at some point I got myself a Garmin watch. The year was 2012 and it was a Garmin Forerunner 410. It had a standard black/grey LCD screen, GPS (where getting a GPS lock could be utterly infuriatingly slow), a sensor you attached to your foot, a sensor you strap to your chest for Heart Rate monitoring, and an ANT+ dongle for connecting to a PC to download your activities. There was even some open source software that someone wrote so I could actually get data off my watch on my Linux laptops. This wasn’t a smart watch – it was exclusively for wearing while exercising and tracking an activity, otherwise it was just a watch.
However, as I was ramping up to marathon distance running, one huge flaw emerged: I was not fast enough to run a marathon in the time that the battery in my Garmin lasted. IIRC it would end up dying around 3hr30min into something, which at the time was increasingly something I’d describe as “not going for too long of a run”. So, the search for a replacement began!
The year was 2017, and the Garmin fenix 5x attracted me for two big reasons: a battery life to be respected, and turn-by-turn navigation. At the time, I seldom went running with a phone, preferring a tiny SanDisk media play (RIP, they made a new version that completely sucked) and a watch. The attraction of being able to get better maps back to where I started (e.g. a hotel in some strange city where I didn’t speak the language) was very appealing. It also had (what I would now describe as) rudimentary smart-watch features. It didn’t have even remotely everything the Pebble had, but it was enough.
So, a (non-trivial) pile of money later (even with discounts), I had myself a shiny and virtually indestructible new Garmin. I didn’t even need a dongle to sync it anywhere – it could just upload via its own WiFi connection, or through Bluetooth to the Garmin Connect app to my phone. I could also (if I ever remembered to), plug in the USB cable to it and download the activities to my computer.
One problem: my skin rebelled against the Garmin fenix 5x after a while. Like, properly rebelled. If it wasn’t coming off, I wanted to rip it off. I tried all of the tricks that are posted anywhere online. Didn’t help. I even got tested for what was the most likely culprit (a Nickel allergy), and didn’t have one of them, so I (still) have no idea what I’m actually allergic to in it. It’s just that I cannot wear it constantly. Urgh. I was enjoying the daily smart watch uses too!
So, that’s one rather expensive watch that is special purpose only, and even then started to get to be a bit of an issue around longer activities. Urgh.
So the hunt began for a smart watch that I could wear constantly. This usually ends in frustration as anything I wanted was hundreds of $ and pretty much nobody listed what materials were in it apart from “stainless steel”, “may contain”, and some disclaimer about “other materials”, which wasn’t a particularly useful starting point for “it is one of these things that my skin doesn’t like”. As at least if the next one also turned out to cause me problems, I could at least have a list of things that I could then narrow down to what I needed to avoid.
So that was all annoying, with the end result being that I went a long time without really wearing a watch. Why? The search resumed periodically and ended up either with nothing, or totally nothing. That was except if I wanted to get further into some vendor lock-in.
Honestly, the only manufacturer of anything smartwatch like which actually listed everything and had some options was Apple. Bizarre. Well, since I already got on the iPhone bandwagon, this was possible. Rather annoyingly, they are very tied together and thus it makes it a bit of a vendor-lock-in if you alternate phone and watch replacement and at any point wish to switch platforms.
That being said though, it does work well and not irritate my skin. So that’s a bonus! If I get back into marathon level distance running, we’ll see how well it goes. But for more common distances that I’ve run or cycled with it… the accuracy seems decent, HR monitor never just sometimes decides I’m not exerting myself, and the GPS actually gets a lock in reasonable time. Plus it can pair with headphones and be the only thing I take out with me.
A few random notes about things that can make life on macOS (the modern one, as in, circa 2023) better for those coming from Linux.
For various reasons you may end up with Mac hardware with macOS on the metal rather than Linux. This could be anything from battery life of the Apple Silicon machines (and not quite being ready to jump on the Asahi Linux bandwagon), to being able to run the corporate suite of Enterprise Software (arguably a bug more than a feature), to some other reason that is also fine.
My approach to most of my development is to have a remote more powerful Linux machine to do the heavy lifting, or do Linux development on Linux, and not bank on messing around with a bunch of software on macOS that would approximate something on Linux. This also means I can move my GUI environment (the Mac) easily forward without worrying about whatever weird workarounds I needed to do in order to get things going for whatever development work I’m doing, and vice-versa.
Terminal emulator? iTerm2. The built in Terminal.app is fine, but there’s more than a few nice things in iTerm2, including tmuxintegration which can end up making it feel a lot more like a regular Linux machine. I should probably go read the tmux integration best practices before I complain about some random bugs I think I’ve hit, so let’s pretend I did that and everything is perfect.
I tend to use the Mac for SSHing to bigger Linux machines for most of my work. At work, that’s mostly to a Graviton 2 EC2 Instance running Amazon Linux with all my development environments on it. At home, it’s mostly a Raptor Blackbird POWER9 system running Fedora.
Running Linux locally? For all the use cases of containers, Podman Desktop or finch. There’s a GUI part of Podman which is nice, and finch I know about because of the relatively nearby team that works on it, and its relationship to lima. Lima positions itself as WSL2-like but for Mac. There’s UTM for a full virtual machine / qemu environment, although I rarely end up using this and am more commonly using a container or just SSHing to a bigger Linux box.
There’s XCode for any macOS development that may be needed (e.g. when you want that extra feature in UTM or something) I do use Homebrew to install a few things locally.
Doing anything close to the kernel/bootloader on PinePhone almost always requires a serial cable, Pine64 store has premade serial cable available for 7$ USD, but making your own serial cable can be both cheaper and more flexible as a DIY cable can support multiple logic level and pinout configuration.
A 3.5mm audio cable, I got mine from a pair of broken headphone
A multimeter for continuity test
A USB-Serial adapter, you can get one online for around 3$ USD, make sure it supports 3.3v logic level if you want to use it with PinePhone
3 jump wires, for TX/RX/GND. Make sure those cables have female endings for connecting to serial adapter
(Optional) Soldering iron, some flux core solder and heat shrink tubing for making proper connection. You can skip this and instead use twisted wires and electrical tape to make connection
The serial pinout of PinePhone is available from this Pine64 Wiki wiki, to put it simply:
If your 3.5mm plug has 3 rings:
|=|=|=|) <-Plug Tip
| | |_RX
| |_Tx
GND
Tip Ring (rightmost): Rx
Middle Ring: Tx
Last (Leftmost): GND
If your 3.5mm plug has 4 rings:
|=|=|=|=|) <-Plug Tip
| | | |_RX
| | |_Tx
| -GND
^---- Not used
Tip Ring (rightmost): Rx
Middle Ring: Tx
Second Middle Ring: GND
Last (leftmost): Unused
With the pinout in mind, cut the headphone cable open and split the wires inside, for a cable with 3 rings there should be 3 seperate wires, and 4 if that’s a 4 ring plug.
Next, remove about 1cm of the isolation layer for each wire, and then use multimeter’s continuity test mode to find out which wire corresponds to which serial pin, it’s likely a good idea to label each wire with pin name at this stage.
Then, cut a jump wire open, strip about 1cm of the isolation layer like with the headphone cable, and twist it together with a wire from the headphone cable, repeat this process 3 times for Tx/Rx/GND (There are many videos on YouTube on this topic). You can also use soldering iron to make stronger.
After finish, test continuity again with multimeter to ensure every wire is properly connected, then protect the joint with electrical tape or heat shrink tubing (which needs to be put on before making connection).
Now the only step left is connecting the jump wire to the serial adapter. Since the PinePhone and the serial adapter are both considered host device, a cross-over connection is required, so what is transmitted can be received on the other side:
--------------- ----------------
serial Tx |------| Rx headphone
adapter Rx |------| Tx cable
side GND |------| GND side
--------------- ----------------
Flip the DIP switch 6 (the rightmost, labeled Headphone) on the PinePhone to enable serial access, connect the newly made cable to the PinePhone and a computer, then use any serial console tool to open a session. The following example uses cu(1) on OpenBSD but screen(1) and minicom(1) should also work.
Last week I had occasion to test deploying ceph-csi on a k3s cluster, so that Kubernetes workloads could access block storage provided by an external Ceph cluster. I went with the upstream Ceph documentation, because assuming everything worked it’d then be really easy for me to say to others “just go do this”.
Everything did not work.
I’d gone through all the instructions, inserting my own Ceph cluster’s FSID and MON IP addresses in the right places, applied the YAML to deploy the provisioner and node plugins, and all the provisioner bits were running just fine, but the csi-rbdplugin pods were stuck in CrashLoopBackOff:
The csi-rbdplugin pod consists of three containers – driver-registrar, csi-rbdplugin, liveness-prometheus – and csi-rbdplugin wasn’t able to load the rbd kernel module:
> kubectl logs csi-rbdplugin-22zjr --container csi-rbdplugin
I0726 10:25:12.862125 7628 cephcsi.go:199] Driver version: canary and Git version: d432421a88238a878a470d54cbf2c50f2e61cdda
I0726 10:25:12.862452 7628 cephcsi.go:231] Starting driver type: rbd with name: rbd.csi.ceph.com
I0726 10:25:12.865907 7628 mount_linux.go:284] Detected umount with safe 'not mounted' behavior
E0726 10:25:12.872477 7628 rbd_util.go:303] modprobe failed (an error (exit status 1) occurred while running modprobe args: [rbd]): "modprobe: ERROR: could not insert 'rbd': Key was rejected by service\n"
F0726 10:25:12.872702 7628 driver.go:150] an error (exit status 1) occurred while running modprobe args: [rbd]
Matching “modprobe: ERROR: could not insert ‘rbd’: Key was rejected by service” in the above was an error on each host’s console: “Loading of unsigned module is rejected”. These hosts all have secure boot enabled, so I figured it had to be something to do with that. So I logged into one of the hosts and ran modprobe rbd as root, but that worked just fine. No key errors, no unsigned module errors. And once I’d run modprobe rbd (and later modprobe nbd) on the host, the csi-rbdplugin container restarted and worked just fine.
So why wouldn’t modprobe work inside the container? /lib/modules from the host is mounted inside the container, the container has the right extra privileges… Clearly I needed to run a shell in the failing container to poke around inside when it was in CrashLoopBackOff state, but I realised I had no idea how to do that. I knew I could kubectl exec -it csi-rbdplugin-22zjr --container csi-rbdplugin -- /bin/bash but of course that only works if the container is actually running. My container wouldn’t even start because of that modprobe error.
Having previously spent a reasonable amount of time with podman, which has podman run, I wondered if there were a kubectl run that would let me start a new container using the upstream cephcsi image, but running a shell, instead of its default command. Happily, there is a kubectl run, so I tried it:
> kubectl run -it cephcsi --image=quay.io/cephcsi/cephcsi:canary --rm=true --command=true -- /bin/bash
If you don't see a command prompt, try pressing enter.
[root@cephcsi /]# modprobe rbd
modprobe: FATAL: Module rbd not found in directory /lib/modules/5.14.21-150400.24.66-default
[root@cephcsi /]# ls /lib/modules/
[root@cephcsi /]#
Ohhh, right, of course, that doesn’t have the host’s /lib/modules mounted. podman run lets me add volume mounts using -v options , so surely kubectl run will let me do that too.
At this point in the story, the notes I wrote last week include an awful lot of swearing.
See, kubectl run doesn’t have a -v option to add mounts, but what it does have is an --overrides option to let you add a chunk of JSON to override the generated pod. So I went back to the relevant YAML and teased out the bits I needed to come up with this monstrosity:
But at least I could get a shell and reproduce the problem:
> kubectl run -it cephcsi-test [honking great horrible chunk of JSON]
[root@cephcsi-test /]# ls /lib/modules/
5.14.21-150400.24.66-default
[root@cephcsi-test /]# modprobe rbd
modprobe: ERROR: could not insert 'rbd': Key was rejected by service
A certain amount more screwing around looking at the source for modprobe and bits of the kernel confirmed that the kernel really didn’t think the module was signed for some reason (mod_verify_sig() was returning -ENODATA), but I knew these modules were fine, because I could load them on the host. Eventually I hit on this:
[root@cephcsi-test /]# ls /lib/modules/*/kernel/drivers/block/rbd*
/lib/modules/5.14.21-150400.24.66-default/kernel/drivers/block/rbd.ko.zst
Wait, what’s that .zst extension? It turns out we (SUSE) have been shipping zstd-compressed kernel modules since – as best as I can tell – some time in 2021. modprobe on my SLE Micro 5.3 host of course supports this:
# grep PRETTY /etc/os-release
PRETTY_NAME="SUSE Linux Enterprise Micro for Rancher 5.3"
# modprobe --version
kmod version 29
+ZSTD +XZ +ZLIB +LIBCRYPTO -EXPERIMENTAL
modprobe in the CentOS Stream 8 upstream cephcsi container does not:
Mystery solved, but I have to say the error messages presented were spectacularly misleading. I later tried with secure boot disabled, and got something marginally better – in that case modprobe failed with “modprobe: ERROR: could not insert ‘rbd’: Exec format error”, and dmesg on the host gave me “Invalid ELF header magic: != \x7fELF”. If I’d seen messaging like that in the first place I might have been quicker to twig to the compression thing.
Anyway, the point of this post wasn’t to rant about inscrutable kernel errors, it was to rant about how there’s no way anyone could be reasonably expected to figure out how to do that --overrides thing with the JSON to debug a container stuck in CrashLoopBackOff. Assuming I couldn’t possibly be the first person to need to debug containers in this state, I told my story to some colleagues, a couple of whom said (approximately) “Oh, I edit the pod YAML and change the container’s command to tail -f /dev/null or sleep 1d. Then it starts up just fine and I can kubectl exec into it and mess around”. Those things totally work, and I wish I’d thought to do that myself. The best answer I got though was to use kubectl debug to make a copy of the existing pod but with the command changed. I didn’t even know kubectl debug existed, which I guess is my reward for not reading the entire manual
So, finally, here’s the right way to do what I was trying to do:
> kubectl debug csi-rbdplugin-22zjr -it \
--copy-to=csi-debug --container=csi-rbdplugin -- /bin/bash
[root@... /]# modprobe rbd
modprobe: ERROR: could not insert 'rbd': Key was rejected by service
(...do whatever other messing around you need to do, then...)
[root@... /]# exit
Session ended, resume using 'kubectl attach csi-debug -c csi-rbdplugin -i -t' command when the pod is running
> kubectl delete pod csi-debug
pod "csi-debug" deleted
In the above kubectl debug invocation, csi-rbdplugin-22zjr is the existing pod that’s stuck in CrashLoopBackOff, csi-debug is the name of the new pod being created, and csi-rbdplugin is the container in that pod that has its command replaced with /bin/bash, so you can mess around inside it.
It’s been a hot minute since my last open source status update! Let’s get caught up, and hopefully we can resume the monthly cadence from here.
Released Hanami 2.0
In Novemver we released Hanami 2.0.0! This was a huge milestone! Both for the Hanami project and the Ruby communuity, but also for us as a development team: we’d spent a long time in the wilderness.
All of this took some doing. It was a mad scramble to get here. The team and I worked non-stop over the preceding couple of months to get this release ready (including me during the mornings of a family trip to Perth).
Anyway, if you’ve followed me here for a while, most of the Hanami 2 features should hopefully feel familiar to you, but if you’d like a refresher, check out the Highlights of Hanami 2.0 that I wrote to accompany the release announcement.
Given I was 100% focused on Hanami dev work until the release, this is probably the least amount of time I’ve had for conference talk preparation, but I was happy with the result. I found a good hook (“new framework, new you�, given the new year approaching) and put together a streamlined introduction to Hanami that fit within the ~20 minutes alotted to the talks (in this case, it was a boon that we hadn’t yet released our view or persistence layers 😆).
Check it out here:
Overhauled hanami-view internals and improved performance
With the 2.0 release done, we decided to release our view and persistence layers progressively, as 2.1 and 2.2 respectively. This would allow us to keep our focus on one thing at a time and improve the timeliness of the upcoming releases.
So over the Christmas break (including several nights on a family trip to the coast), I started work on the first big blocker for our view layer: hanami-view performance. We were slower than Rails, and that just doesn’t cut the mustard for a framework that advertises itself as fast and light.
Finding the right approach here took several goes, and it was finally ready for this pull request at the end of February. I managed to find a >2x performance boost while simplifying our internals, improving the ergonomics of Hanami::View::Context and our part and scope builders, and still retaining all existing features.
Spoke at RubyConf Australia
Also in February, I spoke at RubyConf Australia 2023! After a 3 year hiatus, this was a wonderful reunion for the Ruby community across Australia and New Zealand. It looked like we lost no appetite for these events, so I’m encouraged for next year and beyond.
To fit the homecoming theme, I brought a strong tinge of Australiana to my talk, and expanded it to include a preview of the upcoming view and persistence layers. Check it out:
Created Hanami::View::ERB, a new ERB engine
After performance, the next big issue for hanami-view was having our particular needs met by our template rendering engines, as well as making auto-escaping the default for our “first party supported� engines (ERB, Haml, Slim) that output HTML.
ERB support was an interesting combination of all these issues. For hanami-view, we don’t expect any rendering engine to require explicit capturing of block content. This is what allows methods on parts and scopes simply to yield and have the returned value match content provided to the block from within the template.
To support this with ERB, we previously had to require our users install and use the erbse gem, a little-used and incomplete ERB implementation that provided this implicit block capturing behaviour by default (but did not support auto-escaping of HTML-unsafe values). For a long while we also had to require users use hamlit-block for the same reasons, and as such we had to build a compatibility check between ourselves and Tilt to ensure the right engines were available. This arrangement was awkward and untenable for the kind of developer experience we want for Hanami 2.
So to fix all of this, I wrote our own ERB engine! This provides everything we need from ERB (implicit block capture as well as auto-escaping) and also allows for hanami-view to be used out of the box without requiring manual installation of other gems.
Meanwhile, in the years since my formative work on hanami-view (aka dry-view), Haml and Slim evolved to both use Temple and provide configuration hooks for all the behaviour we require, so this allowed me to drop our template engine compatibility checks and instead just automatically configure Haml or Slim to match our needs if they’re installed.
To support our auto-escaping of HTML-unsafe values, we’ve adopted the Object and String#html_safe? patches that are prevalent across relevant libraries in the Ruby ecosystem. This gives us the broadest possible compatibility, as well as a streamlined and unsurprising user experience. While you might see folks decry monkey patches in general, this is one example where it makes sense for Hanami to take a pragmatic approach, and I’m very pleased with the outcome.
Implemented helpers for hanami-view
After performance and rendering/HTML safety, the last remaining pre-release item for hanami-view was support for helpers. This needed a bit of thinking to sort out, since the new hanami-view provides a significantly different set of view abstractions compared to the 1.x edition.
After this, all helpers should appear whereer you need them in your views, whether in templates, part classes or scope classes. Each slice will also generate a Views::Helpers module to serve as the starting point for your own collection of helpers, too.
With hanami-view providing parts and scopes, the idea is that you can and should use available-everywhere helpers less than before, but they can still be valuable from time to time, and with their introduction, now you have every possible option available for building your views.
Added friendly error pages
While focused on views, I also took the chance to make our error views friendly too. Now we:
Alongside all of this, Luca has been working hard on our support for front end assets via an esbuild plugin and its integration with the framework. This has been nothing short of heroic: he’s been beset by numerous roadblocks but overcome each one, and now we’re getting really close.
Back in June, Luca and I had our first ever pairing session on this work! We got a long way in just a couple of hours. I’m looking forward to pitching in with this as my next focus.
Prepared the Hanami 2.1.0.beta1 release
With all the views work largely squared away, I figured it was time to make a beta release and get this stuff out there for people to test, so we released it as 2.1.0.beta1 at the end of June.
Spoke at Brighton Ruby!
Also at the end of June I spoke at Brighton Ruby! I’ve wanted to attend this event for the longest time, and it did not disappoint. I had a wonderful day at the conference and enjoyed meeting a bunch of new Ruby friends.
For my talk I further evolved the content from the previous iterations, and this time included a look at how we might grow a Hanami app into a more real thing, as well as reflections on what Hanami 2’s release might mean for the Ruby community. I also experimented with a fun new theme and narrative device, which you shall be able to see once the video is out 😜
Thank you so much to Andy for the invitation and the support. ��
Took a holiday
After all of that, I took a break! You might’ve noticed my mentions of all the Hanami work I was doing while ostensibly on family trips. Well, after Brighton Ruby, I was all the way in Europe with the family, and made sure to have a good proper 4 weeks of (bonus summer) holiday. It was fanastic, and I didn’t look at Ruby code one bit.
What’s next
Now that I’m back, I’ll focus on doing whatever is necessary to complete our front end assets integration and get that out as a 2.1 beta2 release. Our new assets stuff is the completely new, so some time for testing and bug fixing will be useful.
Over the rest of the beta period I hope to complete a few smaller general framework improvements and fixes, and from there we can head towards 2.1.0 final.
I suspect it will take at least one more OSS status updates before that all happens, so I can check in with you about it all then!
The July 2023 meeting sparked multiple new topics including Linux security architecture, Debian ports of LoongArch and Risc-V as well as hardware design of PinePhone backplates.
On the practical side, Russell Coker demonstrated running different applications in isolated environment with bubblewrap sandbox, as well as other hardening techniques and the way they interact with the host system. Russell also discussed some possible pathways of hardening desktop Linux to reach the security level of modern Android. Yifei Zhan demonstrated sending and receiving messages with the PineDio USB LoRa adapter and how to inspect LoRa signal with off-the-shelf software defined radio receiver, and discussed how the driver situation for LoRa on Linux might be improved. Yifei then gave a demonstration on utilizing KVM on PinePhone Pro to run NetBSD and OpenBSD virtual machines, more details on running VMs on the PinePhone Pro can be found on this blog post from Yifei.
We also had some discussion of the current state of Mobian and Debian ecosystem, along with how to contribute to different parts of Mobian with a Mobian developer who joined us.
I’ve had a pretty varied experience with photo management on Linux over the past couple of decades. For a while I used f-spot as it was the new hotness. At some point this became…. slow and crashy enough that it was unusable. Today, it appears that the GitHub project warns that current bugs include “Not starting”.
At some point (and via a method I have long since forgotten), I did manage to finally get my photos over to Shotwell, which was the new hotness at the time. That data migration was so long ago now I actually forget what features I was missing from f-spot that I was grumbling about. I remember the import being annoying though. At some point in time Shotwell was no longer was the new hotness and now there is GNOME Photos. I remember looking at GNOME Photos, and seeing no method of importing photos from Shotwell, so put it aside. Hopefully that situation has improved somewhere.
At some point Shotwell was becoming rather stagnated, and I noticed more things stopping to work rather than getting added features and performance. The good news is that there has been some more development activity on Shotwell, so hopefully my issues with it end up being resolved.
One recommendation for Linux photo management was digiKam, and one that I never ended up using full time. One of the reasons behind that was that I couldn’t really see any non manual way to import photos from Shotwell into it.
With tens of thousands of photos (~58k at the time of writing), doing things manually didn’t seem like much fun at all.
As I postponed my decision, I ended up moving my main machine over to a Mac for a variety of random reasons, and one quite motivating thing was the ability to have Photos from my iPhone magically sync over to my photo library without having to plug it into my computer and copy things across.
So…. how to get photos across from Shotwell on Linux to Photos on a Mac/iPhone (and also keep a very keen eye on how to do it the other way around, because, well, vendor lock-in isn’t great).
It would be kind of neat if I could just run Shotwell on the Mac and have some kind of import button, but seeing as there wasn’t already a native Mac port, and that Shotwell is written in Vala rather than something I know has a working toolchain on macOS…. this seemed like more work than I’d really like to take on.
Luckily, I remembered that Shotwell’s database is actually just a SQLite database pointing to all the files on disk. So, if I could work out how to read it accurately, and how to import all the relevant metadata (such as what Albums a photo is in, tags, title, and description) into Apple Photos, I’d be able to make it work.
So… is there any useful documentation as to how the database is structured?
Semi annoyingly, Shotwell is written in Vala, a rather niche programming language that while integrating with all the GObject stuff that GNOME uses, is largely unheard of. Luckily, the database code in Shotwell isn’t too hard to read, so was a useful fallback for when the documentation proves inadequate.
Programming the Mac side of things, it was a good excuse to start looking at Swift, so knowing I’d also need to read a SQLite database directly (rather than use any higher level abstraction), I armed myself with the following resources:
From here, I could work on getting the first half going, the ability to view my Shotwell database on the Mac (which is what I posted a screenshot of back in Feb 2022).
But also, I had to work out what I was doing on the other end of things, how would I import photos? It turns out there’s an API!
A bit of SwiftUI code:
import SwiftUI
import AppKit
import Photos
struct ContentView: View {
@State var favorite_checked : Bool = false
@State var hidden_checked : Bool = false
var body: some View {
VStack() {
Text("Select a photo for import")
Toggle("Favorite", isOn: $favorite_checked)
Toggle("Hidden", isOn: $hidden_checked)
Button("Import Photo")
{
let panel = NSOpenPanel()
panel.allowsMultipleSelection = false
panel.canChooseDirectories = false
if panel.runModal() == .OK {
let photo_url = panel.url!
print("selected: " + String(photo_url.absoluteString))
addAsset(url: photo_url, isFavorite: favorite_checked, isHidden: hidden_checked)
}
}
.padding()
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Combined with a bit of code to do the import (which does look a bunch like the examples in the docs):
import SwiftUI
import Photos
import AppKit
@main
struct SinglePhotoImporterApp: App {
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
func addAsset(url: URL, isFavorite: Bool, isHidden: Bool) {
// Add the asset to the photo library.
let path = "/Users/stewart/Pictures/1970/01/01/1415446258647.jpg"
let url = URL(fileURLWithPath: path)
PHPhotoLibrary.shared().performChanges({
let addedImage = PHAssetChangeRequest.creationRequestForAssetFromImage(atFileURL: url)
addedImage?.isHidden = isHidden
addedImage?.isFavorite = isFavorite
}, completionHandler: {success, error in
if !success { print("Error creating the asset: \(String(describing: error))") } else
{
print("Imported!")
}
})
}
This all meant I could import a single photo. However, there were some limitations.
There’s the PHAssetCollectionChangeRequest to do things to Albums, so it would solve that problem, but I couldn’t for the life of me work out how to add/edit Titles and Descriptions.
It was so close!
So what did I need to do in order to import Titles and Descriptions? It turns out you can do that via AppleScript. Yes, that thing that launched in 1993 and has somehow survived the transition of m68k based Macs to PowerPC based Macs to Intel based Macs to ARM based Macs.
The Photos dictionary for AppleScript
So, just to make it easier to debug what was going on, I started adding code to my ShotwellImporter tool that would generate snippets of AppleScript I could run and check that it was doing the right thing…. but then very quickly ran into a problem…. it appears that the AppleScript language interpreter on modern macOS has limits that you’d be more familiar with in 1993 than 2023, and I very quickly hit limits where the script would just error out before running (I was out of dictionary size allegedly).
But there’s a new option! Everything you can do with AppleScript you can now do with JavaScript – it’s just even less documented than AppleScript is! But it does work! I got to the point where I could generate JavaScript that imported photos, into all the relevant albums, and set title and descriptions.
In my last post, I wrote about how I taught sesdev (originally a tool for deploying Ceph clusters on virtual machines) to deploy k3s, because I wanted a little sandbox in which I could break learn more about Kubernetes. It’s nice to be able to do a toy deployment locally, on a bunch of VMs, on my own hardware, in my home office, rather than paying to do it on someone else’s computer. Given the k3s thing worked, I figured the next step was to teach sesdev how to deploy Longhorn so I could break that learn more about that too.
Install nfs-client, open-iscsi and e2fsprogs packages on all nodes.
Make an ext4 filesystem on /dev/vdb on all the nodes that have extra disks, then mount that on /var/lib/longhorn.
Use kubectl label node -l 'node-role.kubernetes.io/master!=true' node.longhorn.io/create-default-disk=true to ensure Longhorn does its storage thing only on the nodes that aren’t the k3s master.
Install Longhorn with Helm, because that will install the latest version by default vs. using kubectl where you always explicitly need to specify the version.
Create an ingress so the UI is exposed… from all nodes, via HTTP, with no authentication. Remember: this is a sandbox – please don’t do this sort of thing in production!
So, now I can do this:
> sesdev create k3s --deploy-longhorn
=== Creating deployment "k3s-longhorn" with the following configuration ===
Deployment-wide parameters (applicable to all VMs in deployment):
- deployment ID: k3s-longhorn
- number of VMs: 5
- version: k3s
- OS: tumbleweed
- public network: 10.20.78.0/24
Proceed with deployment (y=yes, n=no, d=show details) ? [y]: y
=== Running shell command ===
vagrant up --no-destroy-on-error --provision
Bringing machine 'master' up with 'libvirt' provider…
Bringing machine 'node1' up with 'libvirt' provider…
Bringing machine 'node2' up with 'libvirt' provider…
Bringing machine 'node3' up with 'libvirt' provider…
Bringing machine 'node4' up with 'libvirt' provider…
[... lots more log noise here - this takes several minutes... ]
=== Deployment Finished ===
You can login into the cluster with:
$ sesdev ssh k3s-longhorn
Longhorn will now be deploying, which may take some time.
After logging into the cluster, try these:
# kubectl get pods -n longhorn-system --watch
# kubectl get pods -n longhorn-system
The Longhorn UI will be accessible via any cluster IP address
(see the kubectl -n longhorn-system get ingress output above).
Note that no authentication is required.
…and, after another minute or two, I can access the Longhorn UI and try creating some volumes. There’s a brief period while the UI pod is still starting where it just says “404 page not found”, and later after the UI is up, there’s still other pods coming online, so on the Volume screen in the Longhorn UI an error appears: “failed to get the parameters: failed to get target node ID: cannot find a node that is ready and has the default engine image longhornio/longhorn-engine:v1.4.1 deployed“. Rest assured thisgoes away in due course (it’s not impossible I’m suffering here from rural Tasmanian internet lag pulling container images). Anyway, with my five nodes – four of which have an 8GB virtual disk for use by Longhorn – I end up with a bit less than 22GB storage available:
21.5 GiB isn’t much, but remember this is a toy deployment running in VMs on my desktop Linux box
Now for the fun part. Longhorn is a distributed storage solution, so I thought it would be interesting to see how it handled a couple of types of failure. The following tests are somewhat arbitrary (I’m really just kicking the tyres randomly at this stage) but Longhorn did, I think, behave pretty well given what I did to it.
Volumes in Longhorn consist of replicas stored as sparse files on a regular filesystem on each storage node. The Longhorn documentation recommends using a dedicated disk rather than just having /var/lib/longhorn backed by the root filesystem, so that’s what sesdev does: /var/lib/longhorn is an ext4 filesystem mounted on /dev/vdb. Now, what happens to Longhorn if that underlying block device suffers some kind of horrible failure? To test that, I used the Longhorn UI to create a 2GB volume, then attached that to the master node:
The Longhorn UI helpfully tells me the volume replicas are on node3, node4 and node1
Then, I ssh’d to the master node and with my 2GB Longhorn volume attached, made a filesystem on it and created a little file:
> sesdev ssh k3s-longhorn
Have a lot of fun...
master:~ # cat /proc/partitions
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
8 0 2097152 sda
master:~ # mkfs /dev/sda
mke2fs 1.46.5 (30-Dec-2021)
Discarding device blocks: done
Creating filesystem with 524288 4k blocks and 131072 inodes
Filesystem UUID: 3709b21c-b9a2-41c1-a6dd-e449bdeb275b
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
master:~ # mount /dev/sda /mnt
master:~ # echo foo > /mnt/foo
master:~ # cat /mnt/foo
foo
Then I went and trashed the block device backing one of the replicas:
> sesdev ssh k3s-longhorn node3
Have a lot of fun...
node3:~ # ls /var/lib/longhorn
engine-binaries longhorn-disk.cfg lost+found replicas unix-domain-socket
node3:~ # dd if=/dev/urandom of=/dev/vdb bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes (105 MB, 100 MiB) copied, 0.486205 s, 216 MB/s
node3:~ # ls /var/lib/longhorn
node3:~ # dmesg|tail -n1
[ 6544.197183] EXT4-fs error (device vdb): ext4_map_blocks:607: inode #393220: block 1607168: comm longhorn: lblock 0 mapped to illegal pblock 1607168 (length 1)
At this point, the Longhorn UI still showed the volume as green (healthy, ready, scheduled). Then, back on the master node, I tried creating another file:
master:~ # echo bar > /mnt/bar
master:~ # cat /mnt/bar
bar
That’s fine so far, but suddenly the Longhorn UI noticed that something very bad had happened:
The volume is still usable, but one of the replicas has failed
Ultimately node3 was rebooted and ended up stalled with the console requesting the root password for maintenance:
Failed to mount /var/lib/longhorn – Can’t find ext4 filesystem
Meanwhile, Longhorn went and rebuilt a third replica on node2:
All green again!
…and the volume remained usable the entire time:
master:~ # echo baz > /mnt/baz
master:~ # ls /mnt
bar baz foo lost+found
That’s perfect!
Looking at the Node screen we could see that node3 was still down:
There may be disk size errors with down nodes (4.87 TiB looks a lot like integer overflow to me)
That’s OK, I was able to fix node3. I logged in on the console and ran mkfs.ext4 /dev/vdb then brought the node back up again.The disk remained unschedulable, because Longhorn was still expecting the ‘old’ disk to be there (I assume based on the UUID stored in /var/lib/longhorn/longhorn-disk.cfg) and of course the ‘new’ disk is empty. So I used the Longhorn UI to disable scheduling for that ‘old’ disk, then deleted it. Shortly after, Longhorn recognised the ‘new’ disk mounted at /var/lib/longhorn and everything was back to green across the board.
So Longhorn recovered well from the backing store of one replica going bad. Next I thought I’d try to break it from the other end by running a volume out of space. What follows is possibly not a fair test, because what I did was create a single Longhorn volume larger than the underlying disks, then filled that up. In normal usage, I assume one would ensure there’s plenty of backing storage available to service multiple volumes, that individual volumes wouldn’t generally be expected to get more than a certain percentage full, and that some sort of monitoring and/or alerting would be in place to warn of disk pressure.
With four nodes, each with a single 8GB disk, and Longhorn apparently reserving 2.33GB by default on each disk, that means no Longhorn volume can physically store more than a bit over 5.5GB of data (see the Size column in the previous screenshot). Given that the default setting for Storage Over Provisioning Percentage is 200, we’re actually allowed to allocate up to a bit under 11GB.
So I went and created a 10GB volume, attached that to the master node, created a filesystem on it, and wrote a whole lot of zeros to it:
…there was a lot of unpleasantness on the master node’s console…
So many I/O errors!
…the replicas became unschedulable due to lack of space…
This doesn’t look good
…and finally the volume faulted:
This really doesn’t look good
Now what?
It turns out that Longhorn will actually recover if we’re able to somehow expand the disks that store the replicas. This is probably a good argument for backing Longhorn with an LVM volume on each node in real world deployments, because then you could just add another disk and extend the volume onto it. In my case though, given it’s all VMs and virtual block devices, I can actually just enlarge those devices. For each node then, I:
Shut it down
Ran qemu-img resize /var/lib/libvirt/images/k3s-longhorn_$NODE-vdb.qcow2 +8G
Started it back up again and ran resize2fs /dev/vdb to take advantage of the extra disk space.
After doing that to node1, Longhorn realised there was enough space there and brought node1’s replica of my 10GB volume back online. It also summarily discarded the other two replicas from the still-full disks on node2 and node3, which didn’t yet have enough free space to be useful:
One usable replica is better than three unusable replicas
As I repeated the virtual disk expansion on the other nodes, Longhorn happily went off and recreated the missing replicas:
Finally I could re-attach the volume to the master node, and have a look to see how many of my zeros were actually written to the volume:
master:~ # cat /proc/partitions
major minor #blocks name
254 0 44040192 vda
254 1 2048 vda1
254 2 20480 vda2
254 3 44016623 vda3
8 0 10485760 sda
master:~ # mount /dev/sda /mnt
master:~ # ls -l /mnt
total 7839764
-rw-r--r-- 1 root root 8027897856 May 3 04:41 big-lot-of-zeros
drwx------ 2 root root 16384 May 3 04:34 lost+found
Recall that dd claimed to have written 9039773696 bytes before it stalled when the volume faulted, so I guess that last gigabyte of zeros is lost in the aether. But, recall also that this isn’t really a fair test – one overprovisioned volume deliberately being quickly and deliberately filled to breaking point vs. a production deployment with (presumably) multiple volumes that don’t fill quite so fast, and where one is hopefully paying at least a little bit of attention to disk pressure as time goes by.
It’s worth noting that in a situation where there are multiple Longhorn volumes, assuming one disk or LVM volume per node, the replicas will all share the same underlying disks, and once those disks are full it seems all the Longhorn volumes backed by them will fault. Given multiple Longhorn volumes, one solution – rather than expanding the underlying disks – is simply to delete a volume or two if you can stand to lose the data, or maybe delete some snapshots (I didn’t try the latter yet). Once there’s enough free space, the remaining volumes will come back online. If you’re really worried about this failure mode, you could always just disable overprovisioning in the first place – whether this makes sense or not will really depend on your workloads and their data usage patterns.
All in all, like I said earlier, I think Longhorn behaved pretty well given what I did to it. Some more information in the event log could perhaps be beneficial though. In the UI I can see warnings from longhorn-node-controller e.g. “the disk default-disk-1cdbc4e904539d26(/var/lib/longhorn/) on the node node1 has 3879731200 available, but requires reserved 2505089433, minimal 25% to schedule more replicas” and warnings from longhorn-engine-controller e.g. “Detected replica overprovisioned-r-73d18ad6 (10.42.3.19:10000) in error“, but I couldn’t find anything really obvious like “Dude, your disks are totally full!”
Later, I found more detail in the engine manager logs after generating a support bundle ([…] level=error msg=”I/O error” error=”tcp://10.42.4.34:10000: write /host/var/lib/longhorn/replicas/overprovisioned-c3b9b547/volume-head-003.img: no space left on device”) so the error information is available – maybe it’s just a matter of learning where to look for it.
For the past few years, I have delivered some guest lectures and training for the University of Melbourne master's level course Cluster and Cloud Computing. This year's contribution has been expanded, which is not surprising as the course is apparently required for data science students as well as computer science students. Thus, for 2023 four presentations were given, with the workshop repeated three times! The first two presentations were an introduction to the Linux command line, followed by slightly more advanced content which included an introduction to shell scripting. The third lecture was the main presentation on Supercomputing and the Spartan HPC system in particular. The third presentation was a workshop on HPC job submission and and introduction to OpenMP and MPI programming with a concentration on using MPI4Py.
We – that is to say the storage team at SUSE – have a tool we’ve been using for the past few years to help with development and testing of Ceph on SUSE Linux. It’s called sesdev because it was created largely for SES (SUSE Enterprise Storage) development. It’s essentially a wrapper around vagrant and libvirt that will spin up clusters of VMs running openSUSE or SLES, then deploy Ceph on them. You would never use such clusters in production, but it’s really nice to be able to easily spin up a cluster for testing purposes that behaves something like a real cluster would, then throw it away when you’re done.
I’ve recently been trying to spend more time playing with Kubernetes, which means I wanted to be able to spin up clusters of VMs running openSUSE or SLES, then deploy Kubernetes on them, then throw the clusters away when I was done, or when I broke something horribly and wanted to start over. Yes, I know there’s a bunch of other tools for doing toy Kubernetes deployments (minikube comes to mind), but given I already had sesdev and was pretty familiar with it, I thought it’d be worthwhile seeing if I could teach it to deploy k3s, a particularly lightweight version of Kubernetes. Turns out that wasn’t too difficult, so now I can do this:
> sesdev create k3s
=== Creating deployment "k3s" with the following configuration ===
Deployment-wide parameters (applicable to all VMs in deployment):
deployment ID: k3s
number of VMs: 5
version: k3s
OS: tumbleweed
public network: 10.20.190.0/24
Proceed with deployment (y=yes, n=no, d=show details) ? [y]: y
=== Running shell command ===
vagrant up --no-destroy-on-error --provision
Bringing machine 'master' up with 'libvirt' provider...
Bringing machine 'node1' up with 'libvirt' provider...
Bringing machine 'node2' up with 'libvirt' provider...
Bringing machine 'node3' up with 'libvirt' provider...
Bringing machine 'node4' up with 'libvirt' provider...
[...wait a few minutes(there's lots more log information output here in real life)
...]
=== Deployment Finished ===
You can login into the cluster with:
$ sesdev ssh k3s
…and then I can do this:
> sesdev ssh k3s
Last login: Fri Mar 24 11:50:15 CET 2023 from 10.20.190.204 on ssh
Have a lot of fun…
master:~ # kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 5m16s v1.25.7+k3s1
node2 Ready 2m17s v1.25.7+k3s1
node1 Ready 2m15s v1.25.7+k3s1
node3 Ready 2m16s v1.25.7+k3s1
node4 Ready 2m16s v1.25.7+k3s1
master:~ # kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system local-path-provisioner-79f67d76f8-rpj4d 1/1 Running 0 5m9s
kube-system metrics-server-5f9f776df5-rsqhb 1/1 Running 0 5m9s
kube-system coredns-597584b69b-xh4p7 1/1 Running 0 5m9s
kube-system helm-install-traefik-crd-zz2ld 0/1 Completed 0 5m10s
kube-system helm-install-traefik-ckdsr 0/1 Completed 1 5m10s
kube-system svclb-traefik-952808e4-5txd7 2/2 Running 0 3m55s
kube-system traefik-66c46d954f-pgnv8 1/1 Running 0 3m55s
kube-system svclb-traefik-952808e4-dkkp6 2/2 Running 0 2m25s
kube-system svclb-traefik-952808e4-7wk6l 2/2 Running 0 2m13s
kube-system svclb-traefik-952808e4-chmbx 2/2 Running 0 2m14s
kube-system svclb-traefik-952808e4-k7hrw 2/2 Running 0 2m14s
…and then I can make a mess with kubectl apply, helm, etc.
One thing that sesdev knows how to do is deploy VMs with extra virtual disks. This functionality is there for Ceph deployments, but there’s no reason we can’t turn it on when deploying k3s:
> sesdev create k3s --num-disks=2
> sesdev ssh k3s
master:~ # for node in \
$(kubectl get nodes -o 'jsonpath={.items[*].metadata.name}') ;
do echo $node ; ssh $node cat /proc/partitions ; done
master
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
node3
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
253 16 8388608 vdb
253 32 8388608 vdc
node2
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
253 16 8388608 vdb
253 32 8388608 vdc
node4
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
253 16 8388608 vdb
253 32 8388608 vdc
node1
major minor #blocks name
253 0 44040192 vda
253 1 2048 vda1
253 2 20480 vda2
253 3 44016623 vda3
253 16 8388608 vdb
253 32 8388608 vdc
As you can see this gives all the worker nodes an extra two 8GB virtual disks. I suspect this may make sesdev an interesting tool for testing other Kubernetes based storage systems such as Longhorn, but I haven’t tried that yet.
I recently bought an
Energica
Experia - the latest, largest and longest distance of Energica's
electric motorbike models.
The decision to do this rather than build my own was complicated, and I'm
going to mostly skip over the detail of that. At some time I might put it in
another blog post. But for now it's enough to say that I'd accidentally
cooked the motor in my Mark I, the work on the Mark II was going to take ages,
and I was in the relatively fortunate situation of being able to afford the
Experia if I sold my existing Triumph Tiger Sport and the parts for the Mark
II.
For other complicated reasons I was planning to be in Sydney after the weekend
that Bruce at Zen Motorcycles told
me the bike would be arriving. Rather than have it freighted down, and since
I would have room for my riding gear in our car, I decided to pick it up and
ride it back on the Monday. In reconnoitering the route, we discovered that
by pure coincidence Zen Motorcycles is on Euston Road in Alexandria, only
200 metres away from the entrance to WestConnex and the M8. So with one
traffic light I could be out of Sydney.
I will admit to being more than a little excited that morning. Electric
vehicles are still, in 2023, a rare enough commodity that waiting lists can be
months long; I ordered this bike in October 2022 and it arrived in March 2023.
So I'd had plenty of time to build my expectations. And likewise the thought
of riding a brand new bike - literally one of the first of its kind in the
country (it is the thirty-second Experia ever made!) - was a little daunting.
I obtained PDF copies of the manual and familiarised myself with turning the
cruise control on and off, as well as checking and setting the regen braking
levels. Didn't want to stuff anything up on the way home.
There is that weird feeling in those situations of things being both very
ordinary and completely unique. I met Bruce, we chatted, I saw the other
Experia models in the store, met Ed - who had come down to chat with Bruce,
and just happened to be the guy who rode a Harley Davidson Livewire from
Perth to Sydney and then from Sydney to Cape Tribulation and back. He shared
stories from his trip and tips on hypermiling. I signed paperwork, picked up
the keys, put on my gear, prepared myself.
Even now I still get a bit choked up just thinking of that moment. Seeing
that bike there, physically real, in front of me - after those months of
anticipation - made the excitement real as well.
So finally, after making sure I wasn't floating, and making sure I had my
ear plugs in and helmet on the right way round, I got on. Felt the bike's
weight. Turned it on. Prepared myself. Took off. My partner followed
behind, through the lights, onto the M8 toward Canberra. I gave her the
thumbs up.
We planned to stop for lunch at Mittagong, while the NRMA still offers the
free charger at the RSL there. One lady was charging her Nissan Leaf on the
ChaDeMo side; shortly after I plugged in a guy arrived in his Volvo XC40
Recharge. He had the bigger battery and would take longer; I just needed a
ten minute top up to get me to Marulan.
I got to Marulan and plugged in; a guy came thinking he needed to tell the
petrol motorbike not to park in the electric vehicle bay, but then realised
that the plug was going into my bike. Kate headed off, having charged up as
well, and I waited another ten minutes or so to get a bit more charge. Then
I rode back.
I stopped, only once more - at Mac's Reef Road. I turned off and did a U
turn, then waited for the traffic to clear before trying the bike's
acceleration. Believe me when I say this bike will absolutely do a 0-100km/hr
in under four seconds! It is not a light bike, but when you pull on the power
it gets up and goes.
Here is my basic review, given that experience and then having ridden it for
about ten weeks around town.
The absolute best feature of the Energica Experia is that it is perfectly
comfortable riding around town. Ease on the throttle and it gently takes off
at the traffic lights and keeps pace with the traffic. Ease off, and it
gently comes to rest with regenerative braking and a light touch on the rear
brake after stopping to hold it still. If you want to take off faster, wind
the throttle on more. It is not temperamental or twitchy, and you have no
annoying gears and clutch to balance.
In fact, I feel much more confident lane filtering, because before I would
have to have the clutch ready and be prepared to give the Tiger Sport lots of
throttle lest I accidentally stall it in front of an irate line of traffic.
With the Experia, I can simply wait peacefully - using no power - and then
when the light goes green I simply twist on the throttle and I am away ahead
of even the most aggressive car driver.
It is amazingly empowering.
I'm not going to bore you with the stats - you can probably look them up
yourself if you care. The main thing to me is that it has DC fast charging,
and watching 75KW go into a 22.5KWHr battery is just a little bit terrifying
as well as incredibly cool. The stated range of 250km on a charge at highway
speeds is absolutely correct, from my experience riding it down from Sydney.
And that plus the fast charging means that I think it is going to be quite
reasonable to tour on this bike, stopping off at fast or even mid-level
chargers - even a boring 22KW charger can fill the battery up in an hour.
The touring group I travel with stops often enough that if those stops can be
top ups, I will not hold anyone up.
Some time in the near future I hope to have a nice fine day where I can take
it out on the Cotter Loop. This is an 80km stretch of road that goes west of
Canberra into the foothills of the Brindabella Ranges, out past the Deep
Space Tracking Station and Tidbinbilla Nature Reserve. It's a great
combination of curving country roads and hilly terrain, and reasonably well
maintained as well. I did that on the Tiger Sport, with a GoPro, before I
sold it - and if I can ever convince PiTiVi to actually compile the video
from it I will put that hour's ride up on a platform somewhere.
I want to do that as much to show off Canberra's scenery as to show off the
bike.
And if the CATL battery capacity improvement comes through to the rest of the
industry, and we get bikes that can do 400km to 500km on a charge, then
electric motorbike touring really will be no different to petrol motorbike
touring. The Experia is definitely at the forefront of that change, but it
is definitely possible on this bike.
Rustup (the community package manage for the Rust language) was starting to really suffer : CI times were up at ~ one hour.
We’ve made some strides in bringing this down.
Caching factory for test scenarios
The first thing, which achieved about a 30% reduction in test time was to stop recreating all the test context every time.
Rustup tests the download/installation/upgrade of distributions of Rust. To avoid downloading gigabytes in the test suite, the suite creates mocks of the published Rust artifacts. These mocks are GPG signed and compressed with multiple compression methods, both of which are quite heavyweight operations to perform – and not actually the interesting code under test to execute.
Previously, every test was entirely hermetic, and usually the server state was also unmodified.
There were two cases where the state was modified. One, a small number of tests testing error conditions such as GPG signature failures. And two, quite a number of tests that were testing temporal behaviour: for instance, install nightly at time A, then with a newer server state, perform a rustup update and check a new version is downloaded and installed.
We’re partway through this migration, but compare these two tests:
The former version mutates the date with set_current_dist_date; the new version uses two scenarios, one for the earlier time, and one for the later time. This permits the server state to be constructed only once. On a per-test basis it can move as much as 50% of the time out of the test.
Single binary for the integration test suite
The next major gain was moving from having 14 separate integration test binaries to just one. This reduces the link cost of linking the test binaries, all of which link in the same library. It also permits us to see unused functions in our test support library, which helps with cleaning up cruft rather than having it accumulate.
Hard linking rather than copying ‘rustup-init’
Part of the test suite for each test is setting up an installed rustup environment. Why not start from scratch every time? Well, we obviously have tests that do that, but most tests are focused on steps beyond the new-user case. Setting up an installed rustup environment has a few steps, but particular ones are copying a binary of rustup into the test sandbox, and hard linking it under various names: cargo, rustc, rustup etc.
A debug build of rustup is ~20MB. Running 400 tests means about 8GB of IO; on some platforms most of that IO won’t hit disk, on others it will.
In review now is a PR that changes the initial copy to a hardlink: we hardlink the rustup-init built by cargo into each test, and then hardlink that to the various binaries. That saves 8GB of IO, which isn’t much from some perspectives, but it adds pressure on the page cache, and is wasted work. One wrinkle is a very low max-links limit on NTFS of 1023; to mitigate that we count the links made to rustup-init and generate a new inode for the original to avoid failures happening.
Future work
In GitHub actions this lowers our test time to 19m for Linux, 24m for Windows, which is a lot better but not great.
I plan on experimenting with separate actions for building release artifacts and doing CI tests – at the moment we have the same action do both, but they don’t share artifacts in the cache in any meaningful way, so we can probably gain parallelism there, as well as turning off release builds entirely for CI.
We should finish the cached test context work and use it everywhere.
Also we’re looking at having less integration tests and more narrow close to the code tests.
Unique identifiers for 263 users who received HPC training in 2022 was determined from collected attendee records. Note that users may enrol in multiple courses (e.g., Introduction to Spartan, Advanced Spartan, Parallel Processing, etc) and may return for revision. All these users are counted once only.
From the unique users a total of 212 usernames could be determined from email addresses. When enrolling for training users do not include their Spartan usernmae or their university ID; sometimes they don't even use a university email address, despite requests.
There were 97 users who established an account but did not use Spartan (compute hours = 0). Of the remaining 115 users the total of job hours was determined from trained users was 6280454, after they received training. This calculation ensured that users who had already run jobs on Spartan prior to receiving training was not counted. e.g.,
Back in 2012, I received a box of eight hundred openSUSE 12.1 promo DVDs, which I then set out to distribute to local Linux users’ groups, tech conferences, other SUSE crew in Australia, and so forth. I didn’t manage to shift all 800 DVDs at the time, and I recently rediscovered the remaining three hundred and eighty four while installing some new shelves. As openSUSE 12.1 went end of life in May 2013, it seemed likely the DVDs were now useless, but I couldn’t bring myself to toss them in landfill. Instead, given last week was Hack Week, I decided to use them for an art project. Here’s the end result:
Geeko mosaic made of cut up openSUSE DVDs, on a 900mm x 600mm piece of plywood
Making that mosaic was extremely fiddly. It’s possibly the most annoying Hack Week project I’ve ever done, but I’m very happy with the outcome
The backing is a piece of 900mm x 600mm x 6mm plywood, primed with some leftover kitchen and bathroom undercoat, then spray pained black. I’d forgotten how bad spray paint smells, but it makes for a nice finish. To get the Geeko shape, I took the official openSUSE logo, then turned it into an outline in Inkscape, saved that as a PNG, opened it in GIMP, and cut it into nine 300mm x 200mm pieces which I then printed on A4 paper, stuck together with tape, and cut out to make a stencil. Of course, the first time I did that, nothing quite lined up, so I had to reprint it but with “Ignore page margins” turned off and “Draw crop marks” turned on, then cut the pages down along the crop marks before sticking them together the second time. Then I placed the stencil on the backing, glued the eye down (that just had to be made from the centre of a DVD!) and started laying out cut up DVD shards.
Geeko mosaic work in progress
I initially tried cutting the DVDs with tin snips, which is easy on the hands, but had a tendency to sometimes warp the DVD pieces and/or cause them to delaminate, so I reverted to a large pair of scissors which was more effort but ultimately less problematic.
After placing the pieces that made up the head, tail, feet and spine, and deciding I was happy with how they looked, I glued each piece down with superglue. Think: carefully pick up DVD shard without moving too many other shards, turn over, dab on a few tiny globs of superglue, lower into place, press for a few seconds, move to next piece. Do not get any superglue on your fingers, or you’ll risk sticking your fingers together and/or make a gluey mess on the shiny visible side of the DVD shards.
It was another three sessions of layout-then-glue-down to fill in the body. I think I stuck my fingers together about six, or eight, or maybe twenty times. Also, despite my best efforts to get superglue absolutely nowhere near the stencil at all, when I removed the stencil, it had stuck to the backing in several places. I managed to scrape/cut that off with a combination of fingernails, tweezers, and the very sharp knife in my SLE 12 commemorative Leatherman tool, then touched up the remaining white bits with a fine point black Sharpie.
SLE 12 commemorative Leatherman tool (it seemed appropriate to use this)
Judging from the leftover DVD centre pieces, this mosaic used about 12 DVDs in all, which isn’t very many considering my initial stash. I had a few other ideas for the remainder, mostly involving hanging them up somehow, which I messed around with earlier on while waiting for the paint to dry on the plywood.
One (failed) idea was to use a cutting wheel on my Dremel tool to slice half way through a few DVDs, then slot them into each other to make a hanging thingy that would spin in the wind. I was unable to make a smooth/straight enough cut for this to work, and superglue doesn’t bridge gaps. You can maybe get an idea of what I was aiming at from this photo:
Four DVDs slotted into each other vertically, kinda, one with nasty superglue smear
My wife had an idea for a better way to do this, which is to take a piece of dowel, cut slots in the sides, and glue DVD halves into the slots using Araldite (that’s an epoxy resin, in case you didn’t grow up with that brand name). I didn’t get around to trying this, but I reckon she’s onto something. Next time I’m at the hardware store, I’ll try to remember to pick up some suitably sized dowel.
I did make one somewhat simpler hanging thingy, which I call “Geeko’s Tail (Uncurled)”. It’s just DVDs superglued together on the flat, hanging from fishing line, but I think it’s kinda cool:
No, it’s not an upside down question mark, it’s “Geeko’s Tail (Uncurled)”
Also, I’ve discovered that Officeworks has an e-waste recycling program, so any DVDs I don’t use in future projects needn’t go to landfill.
Most people use their computers (which includes mobile phones) for communication, social media, games, entertainment, office applications, and the like. Most of the time these activities are not particularly onerous in terms of computing as such or do not lead to enormous benefits in productivity, inventions, and discovery. There is one field, however, rarely discussed, that does do this - and that is supercomputing. It is through supercomputing that we are witnessing the most important technological advances of our day, including astronomy, weather and climate forecasting, materials science and engineering, molecular modeling, genomics, neurology, geoscience, and finance - all with numerous success stories.
Usually, I draw a distinction between supercomputing and high-performance computing. Specifically, a supercomputer is any computer system that has exceptional computational power at a particular point in time, many (but not all) of which are measured in the bi-annual Top500 list. Once upon a time dominated by monolithic mainframes supercomputers, in a contemporary sense, are a subset of high-performance computing, which is typically arranged as a cluster of commodity-grade servers with a high-speed interconnect and message-passing software that allows the entire unit to be treated as a whole. One can even put together a "supercomputer" from Raspberry Pi systems, as the University of Southhampton illustrates.
How important is this? For many years now we've known that there is a strong association between research output and access to such systems. Macroeconomic analysis shows that for every dollar invested in supercomputing, there is a return of forty-four dollars in profits or cost-savings. Both these metrics are almost certainly going to increase in time; datasets and problem complexity are growing at a rate greater than the computational performance of personal systems. More researchers need access to supercomputers.
However, researchers do require training to use such systems. The environment, the interface, the use of schedulers on a shared system, the location of data, is all something that needs to be learned. This is a big part of my life; in the last week, I spent three days teaching researchers from the basic of using a supercomputer system to scripting jobs, to using Australia's most powerful system Gadi at NCI, along with contributions at a board meeting of the international HPC Certification Forum. It is often a challenging vocation, but I feel confident that it is making a real difference to our shared lives. For that, I am very grateful.
I gave my amiga 1000 keyboard cable to a friend so she could complete her Amiga 1000 setup. I then ordered some replacement RJ12 cables (4 wires!) to get mine working.
But they didn't.
Let's talk about why.
Firstly - yes, the cable is a RJ12 4P4C rollover cable. Ie, if you hold both connectors up next to each other and aligned the same way, the left hand pins are numbered "1-2-3-4" and the right hand connector is "4-3-2-1". Don't get this backwards or you'll end up reversing the power to the keyboard and damage stuff. It seems most phone cables are 4-wire RJ-12 and rollover pinout, but it's good to double check.
This is different to the early Macintosh keyboard - the RJ12 cable there is straight through. "1-2-3-4" goes to "1-2-3-4".
But it didn't work. I pulled apart the keyboard and started debugging it ... way too hard. The TL;DR is this. When I powered the keyboard from a 5v dedicated supply it was pulling 5v at around 125mA.
The cable I was using, straight from the bag:
The pinout is fine, but each leg has a 40 ohm resistance. There's no way to get 125mA out of 5v at 80 ohm resistance (+5v and GND, 40 ohms each.) The voltage on the keyboard side was closer to 2v.
The one I build/crimped until it worked:
18 ohms now, and can supply ~ 250mA. It was happy with this.
So if you're looking to replace a keyboard cable with an RJ11/RJ12 from Amazon or some other store, double check the pinout, double check that there's 4 wires in the cable, and double-check the series resistance!
I have long said “Long Malaysians, Short Malaysia” in conversation to many. Maybe it took me a while to tweet it, but this was the first example: Dec 29, 2021. I’ve tweeted it a lot more since.
Malaysia has a 10th Prime Minister, but in general, it is a very precarious partnership. Consider it, same shit, different day?
5/n: Otherwise, there will be no change.
So change via “purported democracy” is never going to happen with a country like Malaysia, rotten to the core. It is a crazy dream.
I just have to get off the Malaysian news diet. Malaysians elsewhere, are generally very successful. Malaysians suffering by their daily doldrums, well, they just need to wake up, see the light, and succeed.
In the end, as much as people paraphrase, ask not what the country can do for you, legitimately, this is your life, and you should be taking good care of yourself and your loved ones. You succeed, despite of. Politics and the state happens, regardless of.
Me, personally? Ideas are abound for how to get Malaysians who see the light, to succeed elsewhere. And if I read, and get angry at something (tweet rage?), I’m going to pop RM50 into an investment account, which should help me get off this poor habit. I’ll probably also just cut subscriptions to Malaysian news things… Less exposure, is actually better for you. I can’t believe that it has taken me this long to realise this.
I did poorly blogging last year. Oops. I think to myself when I read, This Thing Still On?, I really have to do better in 2023. Maybe the catalyst is the fact that Twitter is becoming a shit show. I doubt people will leave the platform in droves, per se, but I think we are coming back to the need for decentralised blogs again.
I have 477 days to becoming 40. I ditched the Hobonich Techo sometime in 2022, and just focused on the Field Notes, and this year, I’ve got a Monocle x Leuchtturm1917 + Field Notes combo (though it seems my subscription lapsed Winter 2022, I should really burn down the existing collection, and resubscribe).
2022 was pretty amazing. Lots of work. Lots of fun. 256 days on the road (what a number), 339,551km travelled, 49 cities, 20 countries.
The getting back into doing, and not being afraid of experimenting in public is what 2023 is all about. The Year of The Rabbit is upon us tomorrow, hence why I don’t mind a little later Hello 2023 :)
Get back into the habit of doing. And publishing by learning and doing. No fear. Not that I wasn’t doing, but its time to be prolific with what’s been going on.
Wait, no. I never had one as a kid, I had access to a couple of BBC micros in my primary school for playing a pirate / math educational game that I have since not found online, and I've never really wanted one. Until a close friend's birthday - at which point I got them one.
And then we fell down a rabbit hole together.
So, I bought a dead Electron motherboard. Here you go.
And the ULA - quite a bit of damaged tracks there.
Yes, the ULA is supposedly dead, like a lot of these Electron PCBs. My goal was to strip the PCB of components and make a replica rev4 board. However, first up, i wanted to see if i could repair it.
So, I took off the ULA and fixed up the busted pins. Some copper tape and solder did the trick. One pin was completely missing, and that was quite a challenge to get right.
Then I socketed the 6502 CPU and BASIC/OS ROM. The 6502 was already socketed but the soldering job was pretty bad. I tossed the nice machined socket because it was soldered in bad and I didn't want to clean up all the bad solder from on top of the pins, and I instead just whacked a cheap socket down to test.
Then I powered it up.
Oops. Guess I have a working Acorn Electron. Well, I don't have a case, power supply or keyboard. Guess I'm going to have to make a keyboard for it.
EDIT - the original article has an image of the PCB with the floppy power connector mounted the WRONG WAY.
This is the INCORRECT WAY. Do NOT do it this way!
TL;DR - I'm half way through building an Amiga 500+ replica. The goal:
New PCB
New clear case
Actual floppy drive!
TF534 Accelerator, yes I am interested in FPU stuff for reasons and yes I'm sad about the 4MB of RAM but I'll make do - terriblefire does a great job designing/building/debugging these accelerators and I'm glad they exist!
ECS Denise, also for reasons
2MB chip RAM and some slow RAM too because again why not
3.x ROMs
The challenges!
I need a keyboard for it, but my "donor" machines, like my "donor radios", all now work. Hilarious.
The Amiga 500+ board wasn't well documented for assembly, until I looked. Closer.
Well, the 8375 Agnus I acquired is a PAL one, so I guess I'm building a PAL Amiga 500+. (Which is fine as you can switch it in software after boot, but STILL.)
Oh yeah, floppy drives. Ugh.
Ok, so the PCB. I picked it up from https://www.tindie.com/products/bobsbits/a500-amiga-500-replica-pcb/ . There's a link with the component list, and I got them all with some hunting around. I wish I had a "dead-ish" donor Amiga 500 of suitable vintage to grab parts from, but again, all my machines now work. Ha.
Here's it assembled. Well, mostly.
I still have some connectors and the RTC to add. Yes, it's a 2.x workbench ROM. Yes, it boots to ROM fine.
Now, what do I do about the jumpers? The instructions don't have the Amiga 500+ rev8 PCB jumper descriptions. Ok, they're in the service manuals. And yeah I can read the schematic, but I wanted to be lazy.
Ok, so I started to look at it. I definitely wanted the 1MB/2MB option. I wanted the expansion RAM to show up in chip RAM to start with. Ok, ok. But, guess what. The PCB has them already kinda done.
Here, look closely.
JP3 is already done for us. (For 1MB/2MB I need to have them horizontally jumpered, not vertically.)
And for JP2:
It turns out the two bottom pins are already joined. I'd have to cut the track to start using the expansion RAM slot as slow RAM (in $C00000) or if/when I fit a Gary Adapter / RAM expansion add-on.
Finally, the case is here and the TF534 is installed and boots up to ROM fine.
I'll finish the installation once the sockets arrive - and yes I may go and borrow my rev5 amiga 500 keyboard and Gotek floppy drive emulator until I get suitable replacements. Or, maybe just design an Amiga 500 keyboard drop-in replacement with cheap cherry MX style switches. Why not.
I slipped and bought a TF536 to put into my Amiga 2000. TL;DR is it's now running, but it took a bit of fiddling to get there. When I was last getting it going I noticed it didn't like any Zorro-II RAM in there, so I simply disabled it (it wouldn't do much) and left it alone. The storage card I'm using (a GVP SCSI job) doesn't do DMA to Zorro-II RAM - it does DMA to/from a 64k IO/RAM window which then the driver memcpy()'s out.
Whacking it in with the CPU riser I got from amigastore.eu booted up fine as long as no other RAM cards were installed.
If I installed my storage card or any zorro-II RAM cards it just hung. Not fun.
So then I thought, wait a sec. It's going into the CPU expansion slot, not the CPU socket. And there's this thing called /BOSS which accelerator cards in the CPU expansion slot should assert if they want the DMA and some other signals routed to them rather than the main CPU socket.
So, I grabbed a different one.
This one has a jumper for /BOSS to keep it enabled, and also has the FC0..FC2 pins (indicating the CPU state) also routed.
I plugged this in and bam.
(note I didn't leave the 2MB RAM enabled on the storage card after this test; until I'm ready to screw around with programming stuff that explicitly wants to test Zorro-II/Zorro-III space RAM, I'll leave it off.)
I also tested it with an 8MB Zorro-II RAM expansion (the ZoRAM card that's available on the internet) and it also works fine.
Anyway TL;DR is - don't forget to ensure your accelerator card installation on an Amiga 2000 has /BOSS asserted, or a bunch of DMA/Zorro-II lines won't get routed to the CPU expansion slot and things won't work right.
I like using Catalyst Cloud to host some of my personal sites. In the past I used to use CAcert for my TLS certificates, but more recently I've been using Let's Encrypt for my TLS certificates as they're trusted in all browsers. Currently the LoadBalancer as a Service (LBaaS) in Catalyst Cloud doesn't have built in support for Let's Encrypt. I could use an apache2/nginx proxy and handle the TLS termination there and have that manage the Let's Encrypt lifecycle, but really, I'd rather use LBaaS.
So I thought I'd set about working out how to get Dehydrated (the Let's Encrypt client I've been using) to drive LBaaS (known as Octavia). I figured this would be of interest to other people using Octavia with OpenStack in general, not just Catalyst Cloud.
There's a few things you need to do. These instructions are specific to Debian:
Install and configure Dehydrated to create the certificates for the domain(s) you want.
apt install barbican
Create the LoadBalancer (use the API, ClickOps, whatever), just forward port 80 for now (see sample Apache configs below).
Save the sample hook.sh below to /etc/dehydrated/hook.sh, you'll probably need to customise it, mine is a bit more complicated!
Insert the UUID of your LoadBalancer in hook.sh where LB_LISTENER is set.
Create /etc/dehydrated/catalystcloud/password as described in hook.sh
Save OpenRC file from the Catalyst Cloud dashboard as /etc/dehydrated/catalystcloud/openrc.sh
Install jq, openssl and the openstack tools, on Debian this is:
You should be able to rename the latest certs /var/lib/dehydrated/certs/$DOMAIN and then run dehydrated -c to have it reissue and then deploy a cert.
As we're using HTTP-01 Challenge Type here, you need to have the LoadBalancer forwarding port 80 to your website to allow for the challenge response. It is good practice to have a redirect to HTTPS, here's an example virtual host for Apache:
You all also need this in /etc/apache2/conf-enabled/letsencrypt.conf:
Alias /.well-known/acme-challenge /var/lib/dehydrated/acme-challenges
<Directory /var/lib/dehydrated/acme-challenges>
Options None
AllowOverride None
# Apache 2.x
<IfModule !mod_authz_core.c>
Order allow,deny
Allow from all
</IfModule>
# Apache 2.4
<IfModule mod_authz_core.c>
Require all granted
</IfModule>
</Directory>
And that should be all that you need to do. Now, when Dehydrated updates your certificate, it should update your LoadBalancer as well!
Sample hook.sh:
deploy_cert() {
local DOMAIN="${1}" KEYFILE="${2}" CERTFILE="${3}" FULLCHAINFILE="${4}" \
CHAINFILE="${5}" TIMESTAMP="${6}"
shift 6
# File contents should be:
# export OS_PASSWORD='your password in here'
. /etc/dehydrated/catalystcloud/password
# OpenRC file from the Catalyst Cloud dashboard
. /etc/dehydrated/catalystcloud/openrc.sh --no-token
# UUID of the LoadBalancer to be managed
LB_LISTENER='xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'
# Barbican uses P12 files, we need to make one.
P12=$(readlink -f $KEYFILE \
| sed -E 's/privkey-([0-9]+)\.pem/barbican-\1.p12/')
openssl pkcs12 -export -inkey $KEYFILE -in $CERTFILE -certfile \
$FULLCHAINFILE -passout pass: -out $P12
# Keep track of existing certs for this domain (hopefully no more than 100)
EXISTING_URIS=$(openstack secret list --limit 100 \
-c Name -c 'Secret href' -f json \
| jq -r ".[]|select(.Name | startswith(\"$DOMAIN\"))|.\"Secret href\"")
# Upload the new cert
NOW=$(date +"%s")
openstack secret store --name $DOMAIN-$TIMESTAMP-$NOW -e base64 \
-t "application/octet-stream" --payload="$(base64 < $P12)"
NEW_URI=$(openstack secret list --name $DOMAIN-$TIMESTAMP-$NOW \
-c 'Secret href' -f value) \
|| unset NEW_URI
# Change LoadBalancer to use new cert - if the old one was the default,
# change the default. If the old one was in the SNI list, update the
# SNI list.
if [ -n "$EXISTING_URIS" ]; then
DEFAULT_CONTAINER=$(openstack loadbalancer listener show $LB_LISTENER \
-c default_tls_container_ref -f value)
for URI in $EXISTING_URIS; do
if [ "x$URI" = "x$DEFAULT_CONTAINER" ]; then
openstack loadbalancer listener set $LB_LISTENER \
--default-tls-container-ref $NEW_URI
fi
done
SNI_CONTAINERS=$(openstack loadbalancer listener show $LB_LISTENER \
-c sni_container_refs -f value | sed "s/'//g" | sed 's/^\[//' \
| sed 's/\]$//' | sed "s/,//g")
for URI in $EXISTING_URIS; do
if echo $SNI_CONTAINERS | grep -q $URI; then
SNI_CONTAINERS=$(echo $SNI_CONTAINERS | sed "s,$URI,$NEW_URI,")
openstack loadbalancer listener set $LB_LISTENER \
--sni-container-refs $SNI_CONTAINERS
fi
done
# Remove old certs
for URI in $EXISTING_URIS; do
openstack secret delete $URI
done
fi
}
HANDLER="$1"; shift
#if [[ "${HANDLER}" =~ ^(deploy_challenge|clean_challenge|sync_cert|deploy_cert|deploy_ocsp|unchanged_cert|invalid_challenge|request_failure|generate_csr|startup_hook|exit_hook)$ ]]; then
if [[ "${HANDLER}" =~ ^(deploy_cert)$ ]]; then
"$HANDLER" "$@"
fi
Hello there, friends! This is going to be a short update from me because I’m deep in the throes of Hanami 2.0 release preparation right now. Even still, I didn’t want to let September pass without an update, so let’s take a look.
A story about Hanami::Action memory usage
September started and ended with me looking at the r10k memory usage charts for hanami-controller versus Rails. The results were surprising!
We’d been running some of these checks as part of our 2.0 release prep, the idea being that it’d help us shake out any obvious performance improvements we’d need to make. And it certainly did in this case! Hanami (just like its dry-rb underpinnings) is meant to be the smaller and lighter framework; why were we being outperformced by Rails?
To address this I wrote a simple memory profile script for Hanami::Action inheritance (now checked in here) and started digging.
Total allocated: 184912288 bytes (1360036 objects)
Total retained: 104910880 bytes (780031 objects)
allocated memory by gem
-----------------------------------
56242240 concurrent-ruby-1.1.10
53282480 dry-configurable-0.15.0
34120000 utils-8585be837309
30547488 other
10720080 controller/lib
That’s 185MB allocated for 10k subclasses, with concurrent-ruby, dry-configurable and hanami-utils being the top three gems allocating memory.
This led me straight to dry-configurable, and after a couple of weeks of work, I arrived at this PR, separating our storage of setting definitions from their configured values, among other things. This change allows us to copy less data at the moment of class inheritance, and in the case of a dry-configurable-focused memory profile, cut the allocated memory by more than half.
Total allocated: 32766232 bytes (90004 objects)
Total retained: 32766232 bytes (90004 objects)
allocated memory by gem
-----------------------------------
21486072 other
10880120 dry-configurable-0.16.1
400040 3.1.2/lib
Yes, we brought 185MB allocated memory down to 33MB! This also brought us on par with Rails in the extreme end of the r10k memory usage benchmark:
Here’s a thing though: the way r10k generates actions for its Rails benchmark is to create a single controller class with a method per action. So for the point on the far right of that chart, that’s a single class with 10k methods. Hardly realistic.
So I made a quick tweak to see how things would look if the r10k Rails benchmark generated a class per endpoint like we do with Hanami::Action:
That’s more like it. This is another extreme, however: more realistically, we’d see Rails apps with somewhere between 5-10 actions per controller class, which would lower its dot a little in that graph. In my opinion this would be a useful thing to upstream into r10k. It’s already a contrived benchmark, yes, but it’d be more useful if it at least mimicked realistic application structures.
Either way, we finished the month much more confident that we’ll be delivering on our promise of Hanami as the lighter, faster framework alternative. A good outcome!
Along the way, however, things did feel bleak at times. I wasn’t confident that I’d be able to make things right, and it didn’t feel great to think we might’ve spent years putting somethign together that wasn’t going to be able to deliver on some of those core promises. Luckily, I found all the wins we needed, and learnt a few things along the way.
Hanami 2.0, here we come
What else happened in September? Possibly the biggst thing is that we organised ourselves for the runway towards the final Hanami 2.0.0 release.
We want to do everything possible to make sure the release happens this year, so I spent some time organising the remaining tasks on our Trello board into date-based lists, aiming for a release towards the end of November. It looked achievable! The three of us in the core team re-committed ourselves to doing everything we could to complete these tasks in our estimated timeframes.
So far, things have gone very well!
We’ve all been working tremendously hard, and so far, this has let us keep everything to the schedule. I’ll have a lot to share about our work across October, but that’s all for next month’s update. So in the meantime, I have to put my head back down and get back to shipping a framework. See you all again soon!
It’s been a little over a year since our Redflow ZCell battery and Victron Energy inverter/charger kit were installed on our existing 5.94kW solar array. Now that we’re past the Southern Hemisphere spring equinox it seems like an opportune time to review the numbers and try to see exactly how the system has performed over its first full year. For background information on what all the pieces are and what they do, see my earlier post, Go With The Flow.
As we look at the figures for the year, it’s worth keeping in mind what we’re using the battery for, and how we’re doing it. Naturally we’re using it to store PV generated electricity for later use when the sun’s not shining. We are also charging the battery from the grid at certain times so it can be drawn down if necessary during peak times, for example I set up a small overnight charge to ensure there was power for the weekday morning peak, when the sun isn’t really happening yet, but grid power is more than twice as expensive. More recently in the winter months, I experimented with keeping the battery full with scheduled charges during most non-peak times. This involved quite a bit more grid charging, but got us through a couple of three hour grid outages without a hitch during some severe weather in August.
I spent some time going through data from the VRM portal for the last year, and correlating that with current bills from Aurora energy, and then I tried to compare our last year of usage with a battery, to the previous three years of usage without a battery. For reasons that will become apparent later, this turned out to be a massive pain in the ass, so I’m going to start by looking only at what we can see in the VRM portal for the past year.
The VRM portal has three summary views: System Overview, Consumption and Solar. System Overview tells us overall how much total power was pulled from the grid, how much was exported to the grid, how much was produced locally, and how much was consumed by our loads. The Consumption view (which I wish they’d named “Loads”, because I think that would be clearer) gives us the same consumption figure, but tells us how much of that came from the grid, vs. what came from the battery vs. what came from solar. The Solar view tells us how much PV generation went to the grid, how much went to the battery, and how much was used directly. There is some overlap in the figures from these three views, but there are also some interesting discrepancies, notably: the “From Grid” and “To Grid” figures shown under System Overview are higher than what’s shown in the Consumption and Solar views. But, let’s start by looking at the Consumption and Solar views, because those tell us what the system gives us, and what we’re using. I’ll come back after that to the System Overview, which is where things start to get weird and we discover what the system costs to run.
The VRM portal lets you chose any date range you like to get historical figures and bar charts. It also gives you pie charts of the last 24 hours, 7 days, 30 days and 365 days. To make the figures and bar charts match the pie charts, the year we’re analysing starts at 4pm on September 25, 2021 and ends at 4pm on September 25, 2022, because that’s exactly when I took the following screenshots. This means we get a partial September at each end of the bar chart. I’m sorry about that.
Here’s the Consumption view:
Consumption view from VRM portal, 2021-09-25 16:00 – 2022-09-25 16:00
This shows us that in the last 12 months, our loads consumed 10,849kWh of electricity. Of that, 54% (5,848kWh) came from the grid, 23% (2,506kWh) came direct from solar PV and the final 23% (2,494kWh) came from the battery.
From the rough curve of the bar chart we can see that our consumption is lower in the summer months and higher in the winter months. I can’t say for certain, but I have to assume that’s largely due to heating. The low in February was 638kWh (an average of 22.8kWh/day). The high in July was 1,118kWh (average 36kWh/day).
Now let’s look at the Solar view:
Solar view from VRM portal, 2021-09-25 16:00 – 2022-09-25 16:00
In that same time period we generated 5,640kWh with our solar array, of which 44% (2,506kWh) was used directly by our loads, 43% (2,418kWh) went into the battery and 13% (716kWh) was exported to the grid.
Unsurprisingly our generation is significantly higher in summer than in winter. We got 956kWh (average 30kWh/day) in December but only 161kWh (5.3kWh/day) in June. Peak summer figures like that mean we’ll theoretically be able to do without grid power at all during that period once we get a second ZCell (note that we’re still exporting to the grid in December – that’s because we’ve got more generation capacity than storage). The winter figures clearly indicate that there’s no way we can provide anywhere near all our own power at that time of year with our current generation capacity and loads.
Now look closely at the summer months (December, January and February). There should be a nice curve evident there from December to March, but instead January and February form a weird dip. This is because we were without solar generation for three weeks from January 20 – February 11 due to replacing a faulty MPPT. Based on figures from previous years, I suspect we lost 500-600kWh of potential generation in that period.
Another interesting thing is that if we compare “To Battery” on the Solar view (2,418kWh) with “From Battery” on the Consumption view (2,494kWh), we see that our loads consumed 76kWh more from the battery than we actually put into it with solar generation. This discrepancy is due to the fact that in addition to charging the battery from solar, we’ve also been charging it from the grid at certain times, but the amount of power sent to the battery from the grid isn’t broken out explicitly anywhere in the VRM portal.
Now let’s look at the System Overview:
System Overview view from VRM portal, 2021-09-25 16:00 – 2022-09-25 16:00
Here we see the same figures for “Production” (5,640kWh) and “Consumption” (10,849kWh) as were in the Consumption and Solar views, and the bar chart shows the same consumption and generation curves (ignore the blue overlay and line which indicate battery minimum/maximum and average state of charge – that information is largely meaningless at this scale, given we cycle the battery completely every day).
Now look at “To Grid” and “From Grid”. “To Grid” is 754 kWh, i.e. we somehow sent 38kWh more to the grid than came from solar. “From Grid”, at 8,531kWh, is a whopping 2,683kWh more than the 5,848kWh grid power consumed by our loads (i.e. close to half as much again).
So, what’s going on here?
One factor is that we’re charging the battery from the grid at certain times. Initially that was a few hours overnight and a few hours in the afternoon on weekdays, although the afternoon charge is obviously also provided by the solar if the sun is shining. For all of July, August and most of September though I was using a charge schedule to keep the battery full except for peak times and maintenance cycle nights, which meant quite a bit more grid charging overnight than earlier in the year, as well as grid charging most of the day during days with no or minimal sunshine. Grid power sent to the battery isn’t visible in the “From Grid” figure on the Consumption view – that view shows only our loads, i.e. the equipment the system is powering – but it is part of the “From Grid” figure in the System Overview.
Similarly, some of the power we export to the grid is actually exported from the battery, as opposed to being exported from solar generation. That usually only happens during maintenance cycles when our loads aren’t enough to draw the battery down at the desired discharge rate. But again, same thing, that figure is present here on the system overview page as part of “To Grid”, but of course is not part of the “To Grid” figure on the Solar view.
Another factor is that the system itself needs some amount of power to operate. The Victron kit (the MultiPlus II Inverter/Chargers, the Cerbo GX, the MPPT) use some small amount of power themselves. The ZCell battery also requires power to operate its pumps and fans. When the sun is out this power can of course come from solar. When solar power is not available, power to run the system needs to come from some combination of the remaining charge in the battery, and the grid.
On that note, I did a little experiment to see how much power the system uses just to operate. On July 9 (which happened to be a maintenance cycle day), I disabled all scheduled battery charges, and I shut off the DC isolators for the solar PV, so the battery would remain online (pumps and fans running) but empty for all of July 10. The following day I went and checked the figures on the System Overview, which showed we drew 35kWh, but that our consumption was 33kWh. So, together, the battery doing nothing other than running its pumps and fans, plus the Multis doing nothing other than passing grid power through, used 2kWh of power in 24 hours. Over a year, that’s 730kWh. As mentioned above, ordinarily some of that will be sourced from mains and some from solar, but if we look at the total power that came into the system as a whole (5,640kWh from solar + 8,531kWh from the grid = 14,171kWh), 730kWh is just slightly over 5% of that.
The final factor in play is that a certain amount of power is naturally lost due to conversion at various points. The ZCell has a maximum 80% DC-DC stack efficiency, meaning in the absolute best case if you want to get 10kW out of it, you have to put 12.5kW in. In reality you’ll never hit the best case: the lifetime charge and discharge figures the BMS currenly shows for our ZCell are 4,423 and 3,336kWh respectively, which is a bit over 75%. The Multis have a maximum efficiency of 96% when doing their invert/charge dance, so if we grid charge the battery, we lose at least 4% on the way in, and at least 4% on the way out as well, going to and from AC/DC. Again, in reality that loss will be higher than 4% each way, because 96% is the maximum efficiency.
A bunch of the stuff above just doesn’t apply to the previous system with the ABB inverter and no battery. I also don’t have anything like as much detailed data to go on for the old system, which makes comparing performance with the new system fiendishly difficult. The best comparison I’ve been able to come up with so far involves looking at total power input to the system (power from grid plus solar generation), total consumption by loads (i.e. actual locally usable power), and total power exported.
Prior to the Victron gear and Redflow battery installation, I had grid import and export figures from my Aurora Energy bills, and I had total generation figures from the ABB inverter. From this I can synthesise what are hopefully reasonably accurate load consumption figures by adding adding grid input to total PV generation minus grid export.
I had hoped to do this analysis on a quarterly basis to line up with Aurora bills, because then I would also be able to see how seasonal solar generation and usage went up and down. Unfortunately the billing for 2020 and 2021 was totally screwed up by the COVID-19 pandemic, because there were two quarters during which nobody was coming out to read the electricity meter. The bills for those quarters stated estimated usage (i.e. were wrong, especially given they estimated grid export as zero), with subsequent quarters correcting the figures. I have no way to reliably correlate that mess with my PV generation figures, except on an annual basis. Also, using billing periods from pre-battery years, the closest I can get to the September 25 based 2021-2022 year I’m looking at now is billing periods starting and ending in mid-August. But, that’s close enough. We’ve still got four pretty much back-to-back 12 month periods to look at.
Year
Grid In
Solar In
Total In
Loads
Export
2018-2019
9,031
6,682
15,713
11,827
3,886
2019-2020
9,324
6,468
15,792
12,255
3,537
2020-2021
7,582
6,347
13,929
10,358
3,571
2021-2022
8,531
5,640
14,171
10,849
754
One thing of note here is that in the 2018-2019 and 2019-2020 years, our annual consumption was pretty close to 12MWh, whereas in 2020-2021 and 2021-2022 it was closer to 10.5MWh. If I had to guess, I’d say that ~1.5MWh/year drop is due to a couple of pieces of computer equipment that were previously always on, now mostly running in standby mode except when actually needed. A couple of hundred watts constant draw is a fair whack of power over the course of a year. Another thing to note is the big drop in power exported in 2021-2022, because most of our solar generation is now used locally.
The thing that freaked me out when looking at these figures is that in the battery year, while our loads consumed 491kWh more than in the previous non-battery year, we pulled 949kWh more power in from the grid! This is the opposite of what I had expected to see, especially having previously written:
In the eight months the system has been running we’ve generated 4631kWh of electricity and “only” sent 588kWh to the grid, which means we’ve used 87% of what we generated locally – much better than the pre-battery figure of 45%. I suspect we’ve reduced the amount of power we pull from the grid by about 30% too, but I’ll have to wait until we have a full year’s worth of data to be sure.
When I wrote that, I was looking at August 31, 2021 through April 27, 2022, and comparing that to the August 2020 to May 2021 grid power figures from my old Aurora bills. The mistake I must have made back then was to look at “From Grid” on the Consumption view, rather than “From Grid” on the System Overview. I’ve just done this exercise again, and the total grid draw from our Aurora bills from August 2020 to May 2021 is 4,980kWh. “From Grid” on the Consumption view for August 2021 to May 2022 is 3,575kWh, which is about 30% less, but “From Grid” on the System Overview is 4,754kWh, which is only about 5% less. So our loads pulled about 30% less from the grid than the same time the year before, but our system as a whole didn’t.
Now let’s break our ridiculous September-based year down further into months, to see if we can see more detail. I’ve highlighted some interesting periods in bold.
Month
Grid In
Solar In
Total In
Loads
Export
Sep 21 (part)
153
101
254
213
6
Oct 21
636
629
1,265
988
55
Nov 21
430
747
1,177
866
97
Dec 21
232
956
1,188
767
176
Jan 22
652
450
1,102
822
74
Feb 22
470
430
900
638
83
Mar 22
498
568
1,066
813
64
Apr 22
609
377
986
775
27
May 22
910
238
1,148
953
3
Jun 22
1,114
161
1,275
1073
2
Jul 22
1,163
223
1,386
1118
11
Aug 22
910
375
1,285
966
64
Sep 22 (part)
754
385
1,139
857
92
Total
8,531
5,640
14,171
10,849
754
December is great. We generated about 25% more power than our loads use (956/767=1.25), and our grid input was only about 30% of the total of our loads (232/767=0.30).
January and February show the effects of missing three weeks of potential generation. I mean, just look at December through February 2021-2022 versus the previous three summers.
PV Generation December through January 2018-2022
2018-2019
2019-2020
2020-2021
2021-2022
December
919
882
767
956
January
936
797
818
450
February
699
656
711
430
June and July are terrible. They’re our highest load months, with the lowest solar generation and we pulled 3-4% more power from the grid than our loads actually consumed. I’m going to attribute the latter largely to grid charging the battery.
If I dig a couple of interesting figures out for June and July I see “To Battery” on the Solar view shows 205kWh, and “From Battery” on the Consumption view shows 558kWh. Total consumption in that period was 2,191kWh, with the total “From Grid” reported in System Overview of 2,277kWh. Let’s mess with that a bit.
Bearing in mind the efficiency numbers mentioned earlier, if 205kWh went to the battery from PV, that means no more than 154kWh of what we got out of the battery was from PV generation (remember: real world DC-DC stack efficiency of about 75%). The remaining 404kWh out of the battery is power that went into it from the grid. And that means at least 538kWh in (404/0.75). Note that total from grid for these two months was 86kWh more than the 2,191kWh used by our loads. If I hadn’t been keeping the battery topped up from the grid, I’d’ve saved at least 134kWh of grid power, which would have brought our grid input figure back down below our consumption figure. Note also that this number will actually be higher in reality because I haven’t factored in AC/DC conversion losses from the Multis.
Now let’s look at some costs. When I started trying to compare the new system to the previous system, I went in thinking to look at in in terms of total power input to the system, total consumption by loads, and total power exported. There’s one piece missing there, so let’s add another couple of columns to an earlier table:
Year
Grid In
Solar In
Total In
Loads
Export
Total Out
what?
2021-2022
8,531
5,640
14,171
10,849
754
11,603
2,568
The total usable output of the system was 11,603kWh for 14,171kWh input. The difference between these two figures – 2,568kWh, or about 18% – went somewhere else. Per my earlier experiment, 5% is power that went to actually operate the system components, including the battery. That means about 13% of the power input to the system over the course of the year must have gone to some combination of charge/discharge and AC/DC conversion (in)efficiencies. We can consider this the energy cost of the system. To have the ability to time-shift expensive peak grid electricity, and to run the house without the grid if the sun is out, or from the battery when it has charge, costs us 18% of the total available energy input.
Finally, speaking of expensive grid electricity, let’s look at how much we paid Aurora Energy over the past four years for our power. The bills are broken out into different tariffs, for which you’re charged different amounts per kilowatt hour and then there’s an additional daily supply charge, and also credits for power exported. We can simplify that by just taking the total dollar value of all the power bills and dividing that by the total power drawn from the grid to arrive at an effective cost per kilowatt hour for the entire year. Here it is:
Year
From Grid
Total Bill
Cost/kWh
2018-2019
9,031
$2,278.33
$0.25
2019-2020
9,324
$2,384.79
$0.26
2020-2021
7,582
$1,921.77
$0.25
2021-2022
8,531
$1,731.40
$0.20
So, the combination of the battery plus the switch from Flat Rate to Peak & Off-Peak billing has reduced the cost of our grid power by about 20%. I call that a win.
Going forwards it will be interesting to see how the next twelve months go, and, in particular, what we can do to reduce our power consumption. A significant portion of our power is used by a bunch of always-on computer equipment. Some of that I need for my work, and some of that provides internet access, file storage and email for us personally. Altogether, according to the UPSes, this kit pulls 200-250 watts continuously, but will pull more than that during the day when it’s being used interactively. If we call it 250W continuous, that’s a minimum of 6kWh/day, which is 2,190kWh/year, or about 20% of the 2021-2022 consumption. Some of that equipment should be replaced with newer, more power efficient kit. Some of it could possibly even be turned off or put into standby mode some of the time.
We still need to get a heat pump to replace the 2400W panel heater in our bedroom. That should save a huge amount of power in winter. We’re also slowly working our way through the house installing excellent double glazed windows from Elite Double Glazing, which will save on power for heating and cooling year round.
And of course, we still need to get that second ZCell.
I wanted to put a Kickstart 1.3 ROM in my Amiga 1000. There are adapters out there you can build and install. I chose one, followed the instructions, and it didn't work.
After a whole lot of digging I finally got it working and now I'm documenting what hilarity I found.
I started with this one from the amiga community. The PCB manufacturing files are available on PCBWAY as a shared project. So, I got the board made, did the board mods on my Amiga 1000, and set it up. No bueno.
Let's go over the mods first before I explain why it didn't work.
First up, the Amiga 1000 has a pair of small ROMs (lower and upper 8 bits of the data bus) to bootstrap the ROM image from floppy disk, throw it into the write once memory store and then kick it appropriately to take over the ROM memory address range. The ROM address range is $F80000 -> $FFFFFF - a 512KiB region. But, this ROM isn't that big at all.
The schematic calls out what's going on pretty clearly. This is for the early revision Amiga 1000, with the U5N / U5P ROMs populated.
The /OE lines (pin 22) go to /ROM01 on the PALs, which (among other things) enables the ROMs only when the write-once memory store isn't active and we're in the ROM region.
But look at the other bits going on.
First, pin 1 is going to +5 volts, instead of A16. Pin 27 is going to A15 instead of .. the processor R/W pin? Weird. Anyway, let's look at these ROMs.
First confusing thing here - the ROMs addressing starts from A0 to A14. The 68000 bus however doesn't have an A0 - it's A1 to A23, and then there's upper/lower byte select lines. So, this ROM A0 is the CPU bus A1, the ROM A1 is CPU bus A2, etc.
Pin 1 is NC - it'd be ROM A15 on a 64k x 8 ROM. Ie, Amiga/68000 A16. And pin 27 is ROM 14, Amiga/68000 A15. That makes sense.
What's happening with the OTHER /CS line though?
On U5N/U2N, the /CS2 lines in the schematic to go W2 and W5. The intention looks to be whether A16 or A17 acts as a chip select line to enable either the lower or upper set of ROMs. If you wanted 32KiB ROMs then you'd want A16 to be the /CS2 control. If you wanted 64KiB ROMs then you'd want A17 to be the /CS2 control.
In theory, if everything is wired up fine, this means you can fit 256KiB of ROMs by fitting four 64KiB ROMs and jumpering things appropriately. You'd want:
W2 to be CPU A16
W1 to be CPU A15
W3 to be CPU A14
W4 to be CPU A17
W5 to go via the 74LS04 to invert A17 as the /CS2 line, so either the U5N/U5P is enabled, or the U2N/U2P is enabled.
However, this just plainly didn't match what's on my board. After trying a couple times to do the whole mod, I started to question whether the PCB matched the schematic. Hint, it ... didn't.
Here's what the PCB layout looks like, front:
and back:
You can see where you need to cut W1, W2, W3, W4 (and W5, but I didn't) to turn it into a selectable jumper set.
So, I buzzed out both the ROM board and the Amiga 1000 board to see what was going on. And what I found was ... pretty amusing. I removed all four jumpers and:
68000 D0..D15 are OK
68000 A1..A15 are OK
68000 A16, A17 - not OK!
68000 A18 - OK!
The A18 line made it to the ROM board via one of the wires soldered to the write-once RAM board. The ROM /CS line was soldered to the write-once RAM board as well.
Then I went digging on the ROM board. Let's use ROM numbering now, starting at A0 (cause that's how my notes went.) A0 to A8, A9, A10, A11, A13 used the "even" ROM address lines. A15 used pin 1 on the odd side. A16 on the kickstart ROM mapped to /CS2 on the odd side. A17 on the kickstart ROM mapped to the 4 pin connector and over to the write-once memory board. Same with the ROM /CS line.
So, I had some culprits.
/CS2 maps to ROM A16 which is Amiga/68000 A17. Ok, so maybe I can play with that on the Amiga side using W4, right?
Where the heck was Amiga/68000 A16 being routed?
ROM A15 on odd pin 1 should be controlled by W2, either being Amiga/68000 A16, or +5v, right?
Ok, so then I started buzzing the jumpers and finding out where they went. I then made my first discovery - the trace to ROM /CS2 ? It was tied to CPU A16. No matter what. So, I couldn't flip W4 to the alternate configuration - that shorted ROM /CS2 and CPU A16 to CPU A17. Which means I could not use the /CS2 pin on the ROM adapter, I had to run a separate wire to connect it to CPU A17 and have it end up on the right ROM pin!
Ok, so. I did that. I routed ROM A16 to the middle pin of W4 and ROM A17 to the right hand pin of W4. The rest of the jumpers mirrored the original configuration of the Amiga 1000.
.. but then, nothing. Ok. I went looking at what else could be missing. Then I found the fun reason - the kickstart adapter PCB didn't at all hook up the /BYTE control line to anything. It was just floating. This is problematic for things like DiagROM or the flash based ROM replacements which expect /BYTE to be set correctly for word access. So, I soldered a wire to +5v so it would be tied high and enable word mode.
Success! The ROM booted to a green screen! Ew.
So, in went the Amiga DiagROM. And DiagROM booted! And gave me a lovely screen of horizontal bars! Now, they're supposed to hint at which data line could be busted, but they were all light green and I was told by the author that it may also be not finding enough chip RAM. He suggested a 5V UART directly attached to the UART TX pin on Paula, and that's what I did.
And he was right - it was only detecting 64k of chip RAM.
I was very confused. I slept on it. The next day I fired up the DiagROM again but with some fast RAM attached, so DiagROM would actually start all the way. Then I used the memory editor to edit regions of chip RAM to see how it behaved. The RAM behaved .. fine? Until I looked a bit closer.
The first 64KiB of chip RAM was mirrored in the second.
The third 64KiB of chip RAM was mirrored in the fourth.
etc.
That told me A16 was stuck. But, it couldn't be the whole of A16, or the ROM code wouldn't get very far. No, it was something to do with RAM. Or, to be clear, the address decoding of chip RAM. I had a late night idea that day- what if the bit wasn't stuck, but it .. wasn't being routed?
So I buzzed the chip RAM address bus, here:
These go up to the write-once memory board, so I buzzed A16 on pin 10 of that chip and ... bam. Nothing. No connection to CPU A16.
Then I buzzed the jumpers. And I found the last thing that super surprised me.
The left hand side of W4, that was connected to the CPU A16 and /CS2 line? That pin goes to the RAM A16 line.
And so does the W2 jumper. The left hand side of W2 is RAM A16. The middle is ROM A16. The right is +5v.
So, the PCB routing seems hella wrong there.
So, after removing two pins from my adapter, routing /CS and A17 directly out as wires for A16 and A17, and hooking them up as shown, DiagROM started and all chip RAM was found. When I flipped out the Diag ROM for a Kickstart 1.3 ROM, it also worked fine.
As you can see, the jumper positions are basically where they were for an unmodified board, except that I'm manually grabbing the Amiga/68000 A16/A17 lines and running them to the ROM adapter (and those pins are removed from both odd/even connectors!)
Well, that was fun. "Fun". I have a second Amiga 1000 here, I may choose a different path for its upgrades.
August’s OSS work landed one of the last big Hanami features, saw another Hanami release out the door, began some thinking about memory usage, and kicked off a fun little personal initiative. Let’s dive in!
Conditional slice loading in Hanami
At the beginning of the month I merged support for conditional slice loading in Hanami. I’d wanted this feature for a long time, and in fact I’d hacked in workarounds to achieve the same more than 2 years ago, so I was very pleased to finally get this done, and for the implementation work to be as smooth as it was.
The feature provides a new config.slices setting on your app class, which you can configure like so:
module MyApp
class App < Hanami::App
config.slices = %w[admin]
end
end
For an app consisting of both Admin and Main slices and for the config above, when the app is booted, only the Admin slice will be loaded:
require "hanami/prepare"
Hanami.app.slices.keys # => [:admin]
Admin::Slice # exists, as expected
Main # raises NameError, since it was never loaded
As we see from Main above, slices absent from this list will not have their namespace defined, nor their slice class loaded, nor any of their Ruby source files. Within that Ruby process, they effectively do not exist.
Specifying slices to load can be very helpful to improve boot time and minimize memory usage for specific deployed workloads of your app.
Imagine you have a subset of background jobs that run via a dedicated job runner, but whose logic is otherwise unneeded for the rest of your app to function. In this case, you could organize those jobs into their own slice, and then load only that slice for the job runner’s process. This arrangement would see the job runner boot as quickly as possible (no extraneous code to load) as well as save all the memory otherwise needed by all those classes. You could also do the invserse for your main deployed process: specify all slices except this jobs slice, and you gain savings there too.
Organising code into slices to promote operational efficiency like this also gives you the benefit of greater clarity in the separation of responsibilities between those slices: when a single slice of code is loaded and the rest of your app is made to disappear, that will quickly surface any insidious dependencies from that slice to the rest of your code (they’ll be raised as exceptions!). Cleaning these up will help ensure your slices remain useful as abstractions for reasoning about and maintaining your app.
To make it easy to tune the list of slices to load, I also introduced a new HANAMI_SLICES env var that sets this config without you having to write code inside your app class. In this way, you could use them in your Procfile or other similar deployment code:
This effort was also another example of why I’m so happy to be working alongside the Hanami core team. After initially proposing a more complex arrangement including separate lists for including or excluding slices, Luca jumped in and help me dial this back to the much simpler arrangement of the single list only. For an Hanami release in which we’re going to be introducing so many new ideas, the more we can keep simple around them, the better, and I’m glad to have people who can remind me of this.
Fixed how slice config is applied to component classes
Our action and view integration code relies on their classes detecting when they’re defined inside a slice’s namespace, then applying relevant config from the slice to their own class-level config object. It turned out our code for doing this broke a little when we adjusted our default class hierarchies. Thanks to some of our wonderful early adopters, we picked this up quickly and I fixed it. Now things just work like you expect however you choose to configure your action classes, whether through the app-level config.actions object, or by directly updating config in a base action class.
In doing this work, I became convinced we need an API on dry-configurable to determine whether any config value has been assigned or mutated by the user, since it would help so much in reliably detecting whether or not we should ignore config values at particular levels. For now, we could work around it, but I hope to bring this to dry-configurable at some point in the future.
Released Hanami 2.0.0.beta2
Another month passed, so it was time for another release! With my European colleagues mostly enjoying some breaks over their summer, I hunkered down in chilly Canberra and took care of the 2.0.0.beta2 release. Along with the improvements above, this release also included slice and action generators (hanami generate slice and hanami generate action, thank you Luca!), plus a very handle CLI middlewares inspector (thank you Marc!):
The list of things to do over the beta phase is getting smaller. I don’t expect we’ll need too many more of these releases!
Created memory usage benchmarks for dry-configurable
As the final 2.0 release gets closer, we’ve been doing various performance tests just to make sure the house is in order. One thing we discovered is that Hanami::Action is not as memory efficient as we’d like it to be. One of the biggest opportunities to improve this looked to be in dry-configurable, since that’s what is used to manage the per-class action configuration.
I suspected any effort here would turn out to be involved (and no surprise, it turned out to be involved 😆), so I thought it would be useful as a first step to establish a memory benchmark to revisit over the course of any work. This was also a great way to get my head in this space, which turned out to take over most of my September (but more on that next month).
I was immensitely proud of what Decaf Sucks became, and for the collaboration with Max Wheeler in building it.
Unfortunately, as various internet APIs changed, the site atrophied, eventually became disfunctional, and we had to take it down. I still have the database, however, and I want to bring it back!
This time around, my plan is to do it as a fully open source Hanami 2 example application. Max is even on board to bring back all the UI goodness. For now, you can follow along with the early steps on GitHub. Right now the app is little more than the basic Hanami skeleton with added database integration and a CI setup (Hello Buildkite!), but I plan to grow it bit by bit. Perhaps I’ll try to have something small that I can share with each of these monthly OSS updates.
After Hanami 2 ships, hopefully this will serve as a useful resource for people wanting to see how it plays out in a real working app. And beyond that, I look forward to it serving once again as a place for me to commemorate my coffee travels!
My team at SUSE is working on a new S3-compatible storage solution for Kubernetes, based on Ceph’s RADOS Gateway (RGW), except without any of the RADOS bits. The idea is that you can deploy our s3gw container on top of Longhorn (which provides the underlying replicated storage), and all this is running in your Kubernetes cluster, along with your applications which thus have convenient access to a local S3-compatible object store.
We’ve done this by adding a new storage backend to RGW. The approach we’ve taken is to use SQLite for metadata, with object data stored as files in a regular filesystem. This works quite neatly in a Kubernetes cluster with Longhorn, because Longhorn can provide a persistent volume (think: an ext4 filesystem), on which s3gw can store its SQLite database and object data files. If you’d like to kick the tyres, check out Giuseppe’s deployment tutorial for the 0.2.0 release, but bear in mind that as I’m writing this we’re all the way up to 0.4.0 so some details may have changed.
While s3gw on Longhorn on Kubernetes remains our primary focus for this project, the fact that this thing only needs a filesystem for backing storage means it can be run on top of just about anything. Given “just about anything” includes an old school two node Pacemaker cluster with DRBD for replicated storage, why not give that a try? I kinda like the idea of a good solid highly available S3-compatible storage solution that you could shove into the bottom of a rack somewhere without too much difficulty.
It’s probably eight years since I last deployed Pacemaker and DRBD, so to refresh my memory I ran with SUSE’s latest Highly Available NFS Storage with DRBD and Pacemaker document, but skipped all the NFS bits. That gives a filesystem mounted on one node, which will fail over to the other node if something breaks. On top of that, we need to run the s3gw container, the s3gw-ui container, an nginx HTTPS reverse proxy to smoosh those two together, and a virtual/floating IP, so the whole lot is accessible to the outside world.
Here’s the interesting parts of my Pacemaker configuration:
# crm configure show
[...]
primitive drbd_s3 ocf:linbit:drbd \
params drbd_resource=s3 drbdconf="/etc/drbd.conf" \
op monitor interval=29s role=Master \
op monitor interval=31s role=Slave
primitive fs_s3 Filesystem \
params device="/dev/drbd0" directory="/data" fstype=ext4 \
meta target-role=Started \
op start timeout=60s interval=0 \
op stop timeout=60s interval=0 \
op monitor interval=20s timeout=40s
primitive https nginx \
op start timeout=40s interval=0 \
op stop timeout=60s interval=0 \
op monitor timeout=30s interval=10s \
op monitor timeout=30s interval=30s \
op monitor timeout=60s interval=20s
primitive s3-ip IPaddr2 \
params ip=192.168.100.50 \
op monitor interval=10 timeout=20
primitive s3gw podman \
params image="ghcr.io/aquarist-labs/s3gw:latest" run_opts="-p 7480:7480 -v/data:/data" \
op start interval=0 timeout=90s \
op stop interval=0 timeout=90s \
op monitor interval=30s timeout=30s
primitive s3gw-ui podman \
params image="ghcr.io/aquarist-labs/s3gw-ui:latest" run_opts="-p 8080:8080 -e RGW_SERVICE_URL=https://s3gw.sleha.test" \
op start interval=0 timeout=90s \
op stop interval=0 timeout=90s \
op monitor interval=30s timeout=30s
group g-s3 fs_s3 s3gw s3gw-ui https s3-ip
ms ms-drbd_s3 drbd_s3 \
meta master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 notify=true
colocation col-s3_on_drbd inf: g-s3 ms-drbd_s3:Promoted
order o-drbd_before_fs Mandatory: ms-drbd_s3:promote g-s3:start
[...]
The g-s3 group ensures that the ext4 filesystem (fs_s3), s3gw container (s3gw), s3gw-ui container (s3gw-ui), nginx instance (https) and virtual IP (s3-ip) all run on the same node, and start one after another. The colocation and ordering constraints ensure that g-s3 runs on whichever node is currently the DRBD (ms-drbd_s3) primary.
The important pieces of glue here are:
The fs_s3 resource mounts /dev/drbd0 on /data
The s3gw resource passes -p 7480:7480 -v/data:/data to podman, so the container can write to /data on the host, and the S3 service is accessible via HTTP on port 7480.
The s3gw-ui resource passes -p 8080:8080 -e RGW_SERVICE_URL=https://s3gw.sleha.test to podman, so the UI is accessible via HTTP on port 8080, and it expects the S3 service to be externally available via https://s3gw.sleha.test.
nginx is configured to reverse proxy https://s3gw.sleha.test to http://localhost:7480, and https://s3gw-ui.sleha.test to http://localhost:8080.
I’ve got an entry in /etc/hosts to point s3gw.sleha.test and s3gw-ui.sleha.test at the virtual IP (192.168.100.50).
I’m using self-signed certificates (openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout cert.key -out cert.pem) for s3gw and s3gw-ui, so I had to go visit both https://s3gw.sleha.test and https://s3gw-ui.sleha.test in my browser and accept the SSL certificate before the UI would work.
The DRBD config, nginx config and SSL certificates and keys need to be present on all nodes. I used csync2 for this.
Here’s my /etc/nginx/nginx.conf. I’m not entirely convinced I’ve got everything 100% right here, but it seems to work (this is, incredibly, my first time doing anything with nginx, and my first time dealing with CORS):
Monitoring of processes inside containers is a bit sketchy. By default, it will run podman exec $CONTAINER /bin/true, but that really only proves that the container is alive. You can override that command with something else, but it’s apparently better to engineer your container to die quickly and well if something goes wrong.
So what was the end result? TL;DR: It pretty much All Just WorkedTM, which is exactly what you’d hope for when running a new application on a mature HA stack. I can use s3cmd to mess around with the S3 service, and use my web browser to play with the UI. Failover is nice and quick (think: a few seconds) if I kill a node. For the sake of convenience I did this experiment on a couple of VMs using the external/libvirt STONITH plugin, but I don’t expect a real deployment to be hugely different in behaviour. Also, I’d forgotten how good Pacemaker is at highlighting poorly behaved applications – prior to this experiment the s3gw-ui container didn’t stop well, but we weren’t aware of that until I tried a manual failover which took too long and resulted in an unexpected STONITH due to a stop timeout. Moritz has since fixed that.
One thing I tripped over when doing this deployment was the correct values to use for the access_key and secret_key of the default user when talking to the S3 service. These are actually settable for the s3gw container via the RGW_DEFAULT_USER_ACCESS_KEY and RGW_DEFAULT_USER_SECRET_KEY environment variables, but if left unset, they default to “test” and “test” respectively. The interesting bits of my s3cmd.cfg are thus:
access_key = test
secret_key = test
host_base = https://s3gw.sleha.test/
host_bucket = htts://s3gw.sleha.test/%(bucket)
In retrospect I probably should have added -e RGW_DEFAULT_USER_ACCESS_KEY=tserong -e RGW_DEFAULT_USER_SECRET_KEY=do_not_tell_anyone_this_is_your_password to the run_opts parameter of the s3gw resource in the Pacemaker config.
Hi there friends, it’s certainly been a while, and a lot has happened across May, June and July: I left my job, took some time off, and started a new job. I also managed to get a good deal of open source work done, so let’s take a look at that!
Released Hanami 2.0.0.alpha8
Since we’d skipped a month in our releases, I helped get Hanami 2.0.0.alpha8 out the door in May. The biggest change here was that we’d finished relocating the action and view integration code into the hanami gem itself, wrapped up in distinct “application� classes, like Hanami::Application::Action. In the end, this particular naming scheme turned out to be somewhat short lived! Read on for more :)
Resurrected work using dry-effects within hanami-view
As part of an effort to make it easy to use our conventional view “helpers� in all parts of our view layer, I resurrected my work from September 2020(!) on using dry-effects within hanami-view. The idea here was to achieve two things:
To ensure we keep only a single context object for the entire view rendering, allowing its state to be preserved and accessed by all view components (i.e. allowing both templates, partials and parts all to access the very same context object)
To enable access to the current template/partial’s #locals from within the context, which might help make our helpers feel a little more streamlined through implicit access to those locals
I got both of those working (here’s my work in progress), but I discovered the performance had worsened due to the cost of using an effect to access the locals. I took a few extra passes at this, reducing the number of effects to one, and memoziing it, leaving us with improved performance over the main branch, but with a slightly different stance: the single effect is for accessing the context object only, so any helpers, instead of expecting access to locals, will instead only have access to that context. The job from here will be to make sure that the context object we build for Hanami’s views has everything we need for an ergonomic experience working with our helpers. I’m feeling positive about the direction here, but it’ll be a little while before I get back to it. Read on for more on this (again!).
Unified application and slice
The biggest thing I did over this period was to unify Hanami’s Application and Slice. This one took some doing, and I was glad that I had a solid stretch of time to work on it between jobs.
I already wrote about this back in April’s update, noting that I’d settled on the approach of having a composed slice inside the Hanami::Application class to providing slice-like functionality at the application level. This was the approach I continued with, and as I went, I was able to move more and more functionality out of Hanami::Application and into Hanami::Slice, with that composed “application slice� being the thing that preserved the existing application behaviour. At some point, a pattern emerged: the application is a slice, and we could achieve everything we wanted (and more) by turning class Hanami::Application into class Hanami::Application < Hanami::Slice.
Turning the application into a slice sublcass is indeed how I finished the work, and I’m extremely pleased with how it turned out. It’s made slices so much more powerful. Now, each slice can have its own config, its own dedicated settings and routes, can be run on its own as a Rack application, and can even have its own set of child slices.
As a user of Hanami you won’t be required to use all of this per-slice power features, but they’ll be there if or when you want them. This is a great example of progressive disclosure, a principle I follow as much as possible when designing Hanami’s features: a user should be able to work with Hanami in a simple, straightforward way, and then as their needs grow, they can then find additional capabilities waiting to serve them.
Let’s explore this with a concrete example. If you’re building a simple Hanami app, you can start with a single top-level config/settings.rb that defines all of the app’s own settings. This settings object is made available as a "settings" component registration in both the app as well as all its slices. As the app grows and you add a slice or two, you start to add more slice-specific settings to this component. At this point you start to feel a little uncomfortable that settings specific to SliceA are also available inside SliceB and elsewhere. So you wonder, could you go into slices/slice_a/ and drop a dedicated config/settings.rb there? The answer to that is now yes! Create a config/settings.rb inside any slice directory and it will now become a dedicated settings component for that slice alone. This isn’t a detail you had to burden yourself with in order to get started, but it was ready for you when you needed it.
Another big benefit of this code reorganisation is that the particular responsibilities of Hanami::Application are much clearer: its job is to provide the single entrypoint to the app and coordinate the overall boot process; everything else comes as part of it also being a slice. This distinction is made clear through the number of public methods that exist across the two classes: Application now has only 2 distinct public methods, whereas Slice currently brings 27.
The work here also led to changes across the ecosystem:
Because we’re now importing components from the app into other slices in the root key namespace (rather than prefixed by "application." as before), we needed to make that possible in dry-system.
But with it being possible for each slice to have its own dedicated version of certain components (like "settings" in the example above), we also needed to make dry-system prefer local components when importing.
This is one the reasons I’m excited about Hanami’s use of the dry-rb gems: it’s pushing them in directions no one has had to take them before. The result is not only the streamlined experience we want for Hanami, but also vastly more powerful underpinnings.
Devised a slimmed down core app structure
While I had my head down working on internal changes like the above, Luca had been thinking about Hanami 2 adoption and the first run user experience. As we had opted for a slices-only approach for the duration of our alpha releases, it meant a fairly bulky overall app structure: every slice came with multiple deeply nested files. This might be overwhelming to new users, as well as feeling like overkill for apps that are intended to start small and stay small.
To this end, we agreed upon a stripped back starter structure. Here’s how it looks at its core (ignoring tests and other general Ruby files):
That’s it! Much more lightweight. This approach takes advantage of the Hanami app itself becoming a fully-featured slice, with app/ now as its source directory.
In fact, I took this opportunity to unify the code loading rules for both the app and slices, which makes for a much more intuitive experience. You can now drop any ruby source file into app/ or a slices/[slice_name]/ slice dir and it will be loaded in the same way: starting at the root of each directory, classes defined therein are expected to inhabit the namespace that the app or slice represents, so app/some_class.rb would be MyApp::SomeClass and slices/my_slice/some_class would be MySlice::SomeClass. Hat tip to me of September 2021 for implementing the dry-system namespaces feature that enabled this! 😜
(Yet another little dry-system tweak came out of preparing this too, with Component#file_name now exposed for auto-registration rules).
This new initial structure for starter Hanami 2.0 apps is another example of progressive disclosure in our design. You can start with a simple all-in-one approach, everything inside an app/ directory, and then as various distinct concerns present themselves, you can extract them into dedicated slices as required.
Along with this, some of our names have become shorter! Yes, “application� has become “app� (and Hanami::Application has become Hanami::App, and so on). These shorter names are easier to type, as well as more reflective of the words we tend to use when verbally describing these structures.
We also tweaked our actions and views integration code so that it is automatically available when you inherit directly from Hanami::Action, so it will no longer be necessary to have the verbose Hanami::Application::Action as the superclass for the app’s actions. We also ditched that namespace for both routes and settings too, so now you can just inherit from Hanami::Settings and the like.
Devised a slimmed down release strategy
Any of you following my updates would know by now that the Hanami 2.0 release has been a long time coming. We have ambitious goals, we’re doing our best, and everything is slowly coming together. But as hard as it might’ve been for folks who’re waiting, it’s been doubly so for us, feeling the weight of both the work along with everyone’s expectations.
So to make sure we can focus our efforts and get something out the door sooner rather than later, we decided to stagger our 2.0 release. We’ll start off with an initial 2.0 release centred around hanami, hanami-cli, hanami-controller, and hanami-router (enough to write some very useful API applications, for example), then follow up with a “full stack� 2.1 release including database persistence, views, helpers, assets and everything else.
I’m already feeling empowered by this strategy: 2.0 feels actually achievable now! And all of the other release-related work like updated docs and a migration guide will become correspondingly easier too.
Released Hanami 2.0.0.beta1!
With greater release clarity as well as all the above improvements under our belt, it was time to usher in a new phase of Hanami 2.0 development, so we released 2.0.0.beta1 in July! This new version suffix represents just how close we feel we are to our final vision for 2.0. This is an exciting moment!
And a bunch more
This update is getting rather long, so let me list a bunch of other Hanami improvements I managed to get done:
You can now autoload your app’s constants from within your settings file, which is useful if you’re referring to a types module to type check your settings. This turned out to be a larger change than expected, but it’s further bolstered our slice capabilities, because it led to each slice getting its own Zeitwerk autoloader instance, meaning each slice fully owns its code loading lifecycle.
.env file loading is now a much clearer step upon subclassing Hanami::App, rather than it being a side effect of loading the settings. This is useful in case you want to directly access the ENV for any other purpose.
I removed the settings allowing for customisation of the routes and settings file paths. The further I go with batteries included framework development, the better sense I think I’m developing for what should’t be configurable. This is one such case: we can’t provide reasonable documentation or support if these files can live in arbitrary locations.
Last but not least, I built conditional slice loading! But since this isn’t merged yet, I’ll go into details on this in next month’s update ;)
Outside my Hanami development, a new job and a new computer meant I also took the change to reboot my dotfiles, which are now powered by chezmoi. I can’t speak highly enough of chezmoi, it’s an extremely powerful tool and I’m loving the flexibility it affords!
That’s it from me for now. I’ll come back to you all in another month!
What is HCX? VMware HCX is an application mobility platform designed for simplifying application migration, workload rebalancing and business continuity across datacenters and clouds. VMware HCX was formerly known as Hybrid Cloud Extension and NSX Hybrid Connect.
GCVE HCX GCVE deploys the Enterprise version of HCX as part of the cost of the solution.
HCX Enterprise has the following benefits:
Hybrid Interconnect WAN Optimisation Bulk Migration, Live Migration and HCX Replication Assisted vMotion Cloud to cloud migration Disaster Protection KVM & Hyper-V to vSphere migrations Traffic Engineering Mobility Groups Mobility Optimised Networking Changeover scheduling Definitions Cold Migration
We have seen a lot of Google Cloud VMware Engine over the last few months and for the entire time we have used click-ops to provision new infrastructure, networks and VM’s. Now we are going to the next level and we will be using Terraform to manage our infrastructure as code so that it is version controlled and predictable.
Installing Terraform The first part of getting this working is installing Terraform on your local machine.
As described in some detail in my last post, we have a single 10kWh Redflow ZCell zinc bromine flow battery hooked up to our solar PV via Victron inverter/chargers. This gives us the ability to:
Store almost all the excess energy we generate locally for later use.
When the sun isn’t shining, grid charge the battery at off-peak times then draw it down at peak times to save on our electricity bill (peak grid power is slightly more than twice as expensive as off-peak grid power).
Opportunistically survive grid outages, provided they don’t happen at the wrong time (i.e. when the sun is down and the battery is at 0% state of charge).
By their nature, ZCell flow batteries needs to undergo a maintenance cycle at least every three days, where they are discharged completely for a few hours. That’s why the last point above reads “opportunistically survive grid outages”. With a single ZCell, we can’t use the “minimum state of charge” feature of the Victron kit to always keep some charge in the battery in case of outages, because doing so conflicts with the ZCell maintenance cycles. Once we eventually get a second battery, this problem will go away because the maintenance cycles automatically interleave. In the meantime though, as my project for Hack Week 21, I decided to see if I could somehow automate the Victron scheduled charge configuration based on the ZCell maintenance cycle timing, to always keep the battery as full as possible for as long as possible.
There are three goals somewhat in tension with each other here:
Keep the battery full, except during maintenance cycles.
Don’t let the battery get too full immediately before a maintenance cycle, lest the discharge take too long and maintenance still be active the following morning.
Don’t schedule charges during peak electricity times (we still want to draw the battery down then, to avoid using the expensive gold plated electrons the power company sends down the wire between 07:00-10:00 and 16:00-21:00).
Here’s the solution I came up with:
On non-maintenance cycle days, set two no-limit scheduled charges, one from 10:00 for 6 hours, the other from 21:00 for 10 hours. That means the battery will be charged from the grid and/or the sun continuously, except for peak electricity times, when it will be drawn down. Our loads aren’t high enough to completely deplete the battery during peak times, so there will always be some juice in case of a grid outage on non-maintenance cycle days.
On maintenance cycle days, set a 50% limit scheduled charge from 13:00 for 3 hours, so the battery won’t be too full before that evening’s maintenance cycle, which kicks in at sunset. The day after a maintenance cycle, set a no limit scheduled charge from 03:00 for 4 hours. At our site, maintenance has almost always finished before 03:00, so there’s no conflict here, and we still have time to get some charge into the battery to handle the next morning’s peak.
Now, how to automate that?
The ZCell Battery Management System (BMS) has a REST API which we can query to find out useful information about the battery. Unfortunately it won’t actually tell us for certain whether maintenance will be run on any given day, but we can get the maintenance time limit, and subtract from that the amount of time that’s passed since the last maintenance cycle. If the resultant figure is less than one day, we know that maintenance will happen today. It is possible for maintenance to happen at other times, e.g. I can force maintenance manually, and also it can happen more often than every three days if you mess with the allowed days setting in the BMS, so this solution arguably isn’t perfect, but I think it’s good enough under the circumstances, at least at our site.
The Victron Cerbo GX (the little box that controls everything) runs Linux, and you can easily get root on it, so it’s possible to write scripts that run locally there. Here’s what I ended up with:
One important point about installing things on the Cerbo GX, is that the root partition is overwritten during firmware updates, but there’s a separate data partition which is preserved. The root user’s home directory is symlinked to /data/home/root, so my script lives at /data/home/root/sched.py to ensure it remains present. Then we need to get it into /etc/crontab, which doesn’t survive firmware updates. This is done by adding a /data/rc.local script which the Cerbo GX runs on boot:
After a few days of testing and observation, I can confirm that it all works perfectly! At least, at our site, right now, with our current loads and daylight ours. The whole thing will want revisiting (or probably just turning off) as we get into summer, when we’ll be able to rely on significantly more sunlight to keep the battery full than we get now. I may well just go back to a single 03:00-for-four-hours grid charge then, once the days are nice and long. See how we go…
Last week I finished up at Culture Amp, and I’m excited to announce that I’ll be joining Buildkite as an engineer!
My time at Culture Amp was special. It was my first role after a decade of running Icelab with Max and Michael. Culture Amp hired everyone at Icelab after we decided to close the business, providing both a smooth transition and new opportunities to a singular group. I built a great working relationship with my manager, I was trusted to do big things, and I relished the chance to work with and learn from a large group of engineers. I’m deeply thankful for all of this.
Towards the end, I was serving as Culture Amp’s Director of Back End Engineering, and moving into engineering management. However, as any astute reader of this blog might attest, I am deeply motivated by hands on programming work, and all the learning and collaboration opportunities that go with it. I realised it was not the time to draw that chapter to a close (it might never!), and through that consideration I connected with Buildkite.
I’m excited to join Buildkite for many reasons! It’s a great Australian company with heart and personality. It brims with people I’ve long dreamt of working with. Developer tooling is an area close to my heart. And they’re growing a (majestic) Ruby app at the core of their tech. I can’t wait to dig in.
For me, this is also an intentional decision to stick with Ruby. The work I’m doing in Ruby OSS right now might be one of the biggest “dents in the universe” I get to make. I want to see this effort through, to complete our vision for Hanami 2.0, then learn from how it’s adopted by our community.
I have some time off between jobs, which I’ll use to give our Hanami work a real boost: I’ll be commiting nearly 6 weeks of full-time work to Hanami! Based on previous experience, this should see me get through what otherwise might have taken 6 months of part-time effort. I’m hoping this will get us significantly closer to 2.0. I’ll likely start another tweet thread of my efforts, so find me on Twitter if you’d like to follow along!
Picking up where we left off last month, let’s dive into disaster recovery and how to use Site Recovery Manager and Google Backup & Protect to DR into and within the cloud with GCVE.
But before we do, a quick advertisement:
If you are in Brisbane, Australia, I suggest coming to the awesome Google Infrastructure Group (GIG) which focuses on GCVE where on 04 July 2022 I will be presenting on Terraform in GCVE.
Let’s pick up where we left off from last months article and start setting up some of the features of GCVE, starting with Advanced Autoscaling.
What is Advanced Auto-Scaling? Advanced Autoscaling automatically expands or shrinks a private cloud based on CPU, memory and storage utilisation metrics.
GCVE monitors the cluster based on the metrics defined in the autoscale policy and decides to add or remove nodes automatically. Remember: GCVE is physical Dell Poweredge servers, not a container/VM running in Docker or on a hypervisor like VMware.
We’ve done this a number of times over the last decade, from OSDC to LCA. The idea is to provide a free psychologist or counsellor at an in-person conference. Attendees can do an anonymous booking by taking a stickynote (with the timeslot) from a signup sheet, and thus get a free appointment.
Many people find it difficult taking the first (very important) step towards getting professional help, and we’ve received good feedback that this approach indeed assists.
So far we’ve always focused on open source conferences. Now we’re moving into information security! First BrisSEC 2022 (Friday 29 April at the Hilton in Brisbane, QLD) and then AusCERT 2022 (10-13 May at the Star Hotel, Gold Coast QLD). The awesome and geek friendly Dr Carla Rogers will be at both events.
How does this get funded? Well, we’ve crowdfunded some, nudged sponsors, most mostly it gets picked up by the conference organisers (aka indirectly by the sponsors, mostly).
If you’re a conference organiser, or would like a particular upcoming conference to offer this service, do drop us a line and we’re happy to chase it up for you and help the organisers to make it happen. We know how to run that now.
In-person is best. But for virtual conferences, sure contact us as well.
The hack day didn’t go as well as I hoped, but didn’t go too badly. There was smaller attendance than hoped and the discussion was mostly about things other than FLOSS. But everyone who attended had fun and learned interesting things so generally I think it counts as a success. There was discussion on topics including military hardware, viruses (particularly Covid), rocketry, and literature. During the discussion one error in a Wikipedia page was discussed and hopefully we can get that fixed.
I think that everyone who attended will be interested in more such meetings. Overall I think this is a reasonable start to the Hack Day meetings, when I previously ran such meetings they often ended up being more social events than serious hacking events and that’s OK too.
One conclusion that we came to regarding meetings is that they should always be well announced in email and that the iCal file isn’t useful for everyone. Discussion continues on the best methods of announcing meetings but I anticipate that better email will get more attendance.
What is GCVE? Google Cloud VMware Engine, or GCVE, is a fully managed VMware hypervisor and associated management and networking components, (vSphere, NSX-T, vSAN and HCX) built on top of Google’s highly performant and scalable infrastructure with fully redundant and dedicated 100Gbps networking that provides 99.99% availability.
The solution is integrated into Google Cloud Platform, so businesses benefit from having full access to GCP services, native VPC networking, Cloud VPN or Interconnect as well as all the normal security features you expect from GCP.
The March 2022 meeting went reasonably well. Everyone seemed to have fun and learn useful things about computers. After 2 hours my Internet connection dropped out which stopped the people who were using VMs from doing the tutorial. Fortunately most people seemed ready for a break so we ended the meeting. The early and abrupt ending of the meeting was a disappointment but it wasn’t too bad, the meeting would probably only have gone for another half hour otherwise.
The BigBlueButton system was shown to be effective for training when one person got confused with the Debian package configuration options for Postfix and they were able to share the window with everyone else to get advice. I was also confused by that stage.
Future Meetings
The main feature of the meeting was training in setting up a mailserver with Postfix, here are the lecture notes for it [1]. The consensus at the end of the meeting was that people wanted more of that for the April meeting. So for the April meeting I will add to the Postfix Training to include SpamAssassin, SPF, DKIM, and DMARC. For the start of the next meeting instead of providing bare Debian installations for the VMs I’ll provide a basic Postfix/Dovecot setup so people can get straight into SpamAssassin etc.
For the May meeting training on SE Linux was requested.
Social Media
Towards the end of the meeting we discussed Matrix and federated social media. LUV has a Matrix server and I can give accounts to anyone who’s involved in FOSS in the Australia and New Zealand area. For Mastodon the NZOSS Mastodon server [2] seems like a good option. I have an account there to try Mastodon, my Mastodon address is @etbe@mastodon.nzoss.nz .
We are going to make Matrix a primary communication method for the Flounder group, the room is #flounder:luv.asn.au . My Matrix address is @etbe:luv.asn.au .
We also have a new URL for the blog and events. See the right sidebar for the link to the iCal file which can be connected to Google Calendar and most online calendaring systems.
We just had the first Flounder meeting which went well. Had some interesting discussion of storage technology, I learnt a few new things. Some people did the ZFS training and BTRFS training and we had lots of interesting discussion.
Andrew Pam gave a summary of new things in Linux and talked about the sites lwn.net, gamingonlinux.com, and cnx-software.com that he uses to find Linux news. One thing he talked about is the latest developments with SteamDeck which is driving Linux support in Steam games. The site protondb.com tracks Linux support in Steam games.
We had some discussion of BPF, for an introduction to that technology see the BPF lecture from LCA 2022.
Next Meeting
The next meeting (Saturday 5th of March 1PM Melbourne time) will focus on running your own mail server which is always of interest to people who are interested in system administration and which is probably of more interest than usual because of Google forcing companies with “a legacy G Suite subscription” to transition to a more expensive “Business family” offering.
I “recently” wrote about obtaining a new (to me, actually quite old) computer over in The Apple Power Macintosh 7200/120 PC Compatible (Part 1). This post is a bit of a detour, but may help others understand why some images they download from the internet don’t work.
Disk partitioning is (of course) a way to divide up a single disk into multiple volumes (partitions) for different uses. While the idea is similar, computer platforms over the ages have done this in a variety of different ways, with varying formats on disk, and varying limitations. The ones that you’re most likely to be familiar with are the MBR partitioning scheme (from the IBM PC), and the GPT partitioning scheme (common for UEFI systems such as the modern PC and Mac). One you’re less likely to be familiar with is the Apple Partition Map scheme.
The way all IBM PCs and compatibles worked from the introduction of MS-DOS 2.0 in 1983 until some time after 2005 was the Master Boot Record partitioning scheme. It was outrageously simple: of the first 512 byte sector of a disk, the first 446 bytes was for the bootstrapping code (the “boot sector”), the last 2 bytes were for the magic two bytes telling the BIOS this disk was bootable, and the other 64 bytes were four entries of 16 bytes, each describing a disk partition. The Wikipedia page is a good overview of what it all looks like. Since “four partitions should be enough for anybody” wasn’t going to last, DOS 3.2 introduced “extended partitions” which was just using one of those 4 partitions as another similar data structure that could point to more partitions.
In the 1980s (similar to today), the Macintosh was, of course, different. The Apple Partition Map is significantly more flexible than the MBR on PCs. For a start, you could have more than four partitions! You could actually have a lot more than four partitions, as the Apple Partition Map is a single 512-byte sector for each partition, and the partition map is itself a partition. Instead of being block 0 (like the MBR is), it actually starts at block 1, and is contiguous (The Driver Descriptor Record is what’s at block 0). So, once created, it’s hard to extend. Typically it’d be created as 64×512-byte entries, for 32kb… which turns out is actually about enough for anyone.
The Inside Macintosh reference on the SCSI Manager goes through more detail as to these structures. If you’re wondering what language all the coding examples are in, it’s Pascal – which was fairly popular for writing Macintosh applications in back in the day.
But the actual partition map isn’t the “interesting” part of all this (and yes, the quotation marks are significant here), because Macs are pretty darn finicky about what disks to boot off, which gets to be interesting if you’re trying to find a CD-ROM image on the internet from which to boot, and then use to install an Operating System from.
I never programmed a 1980s Macintosh actually in the 1980s. It was sometime in the early 1990s that I first experienced Microsoft Basic for the Macintosh. I’d previously (unknowingly at the time as it was branded Commodore) experienced Microsoft BASIC on the Commodore 16, Commodore 64, and even the Apple ][, but the Macintosh version was something else. It let you do some pretty neat things such as construct a GUI with largely the same amount of effort as it took to construct a Text based UI on the micros I was familiar with.
Okay, to be fair, I’d also dabbled in Microsoft QBasic that came bundled with MS-DOS of the era, which let you do a whole bunch of graphics – so you could theoretically construct a GUI with it. Something I did attempt to do. Programming on the Mac was so much easier to construct a GUI.
Of course, Microsoft Basic wasn’t the preferred way to program on the Macintosh. At that time it was largely Pascal, with C being something that also existed – but you were going to see Pascal in Inside Macintosh. It was probably somewhat fortuitous that I’d poked at Pascal a bit as something alternate to look at in the high school computing classes. I can only remember using TurboPascal on DOS systems and never actually writing Pascal on the Macintosh.
By the middle part of the 1990s though, I was firmly incompetently writing C on the Mac. No doubt the quality of my code increased after I’d done some university courses actually covering the language rather than the only practical way I had to attempt to write anything useful being looking at Inside Macintosh examples in Pascal and “C for Dummies” which was very not-Macintosh. Writing C on UNIX/Linux was a lot easier – everything was made for it, including Actual Documentation!
Anyway, in the early 2000s I ran MacOS X for a bit on my white iBook G3, and did a (very) small amount of any GUI / Project Builder (the precursor to Xcode) related development – instead largely focusing on command line / X11 things. The latest coolness being to use Objective-C to program applications (unless you were bringing over your Classic MacOS Carbon based application, then you could still write C). Enter some (incompetent) Objective-C coding!
Then Apple went to x86, so the hardware ceased being interesting, and I had no reason to poke at it even as a side effect of having hardware that could run the software stack. Enter a long-ass time of Debian, Ubuntu, and Fedora on laptops.
Come 2022 though, and (for reasons I should really write up), I’m poking at a Mac again and it’s now Swift as the preferred way to write apps. So, I’m (incompetently) hacking away at Swift code. I have to admit, it’s pretty nice. I’ve managed to be somewhat productive in a relative short amount of time, and all the affordances in the language gear towards the kind of safety that is a PITA when coding in C.
So this is my WIP utility to be able to import photos from a Shotwell database into the macOS Photos app:
There’s a lot of rough edges and unknowns left, including how to actually do the import (it looks like there’s going to be Swift code doing AppleScript things as the PhotoKit API is inadequate). But hey, some incompetent hacking in not too much time has a kind-of photo browser thing going on that feels pretty snappy.
Recently I read Michael Snoyman’s post on combining Axum, Hyper, Tonic and Tower. While his solution worked, it irked me – it seemed like there should be a much tighter solution possible.
I can deep dive into the code in a later post perhaps, but I think there are four points of difference. One, since the post was written Axum has started boxing its routes : so the enum dispatch approach taken, which delivers low overheads actually has no benefits today.
Two, while writing out the entire type by hand has some benefits, async code is much more pithy.
Thirdly, the code in the post is entirely generic, except the routing function itself.
And fourth, the outer Service<AddrStream> is an unnecessary layer to abstract over: given the similar constraints – the inner Service must take Request<..>, it is possible to just not use a couple of helpers and instead work directly with Service<Request...>.
So, onto a pithier version.
First, the app server code itself.
use std::{convert::Infallible, net::SocketAddr};
use axum::routing::get;
use hyper::{server::conn::AddrStream, service::make_service_fn};
use hyper::{Body, Request};
use tonic::async_trait;
use demo::echo_server::{Echo, EchoServer};
use demo::{EchoReply, EchoRequest};
struct MyEcho;
#[async_trait]
impl Echo for MyEcho {
async fn echo(
&self,
request: tonic::Request<EchoRequest>,
) -> Result<tonic::Response<EchoReply>, tonic::Status> {
Ok(tonic::Response::new(EchoReply {
message: format!("Echoing back: {}", request.get_ref().message),
}))
}
}
#[tokio::main]
async fn main() {
let addr = SocketAddr::from(([0, 0, 0, 0], 3000));
let axum_service = axum::Router::new().route("/", get(|| async { "Hello world!" }));
let grpc_service = tonic::transport::Server::builder()
.add_service(EchoServer::new(MyEcho))
.into_service();
let both_service =
demo_router::Router::new(axum_service, grpc_service, |req: &Request<Body>| {
Ok::<bool, Infallible>(
req.headers().get("content-type").map(|x| x.as_bytes())
== Some(b"application/grpc"),
)
});
let make_service = make_service_fn(move |_conn: &AddrStream| {
let both_service = both_service.clone();
async { Ok::<_, Infallible>(both_service) }
});
let server = hyper::Server::bind(&addr).serve(make_service);
if let Err(e) = server.await {
eprintln!("server error: {}", e);
}
}
Note the Router: it takes the two services and Fn to determine which to use on any given request. Then we just drop that composed service into make_service_fn and we’re done.
Next up we have the Router implementation. This is generic across any two Service<Request<...>> types as long as they are both Into<Bytes> for their Data, and Into<Box<dyn Error>> for errors.
Interesting things here – I use boxed_unsync to abstract over the body concrete type, and I implement the future using async code rather than as a separate struct. It becomes much smaller even after a few bits of extra type constraining.
One thing that flummoxed me for a little was the need to capture the future for the underlying response outside of the async block. Failing to do so provokes a 'static requirement which was tricky to debug. Fortunately there is a bug on making this easier to diagnose in rustc already. The underlying problem is that if you create the async block, and then dereference self, the type for impl of .first has to live an arbitrary time. Whereas by capturing the future immediately, only the impl of the future has to live an arbitrary time, and that doesn’t then require changing the signature of the function.
This is almost worth turning into a crate – I couldn’t see an existing one when I looked, though it does end up rather small – < 100 lines. What do you all think?
The first meeting will start at 1PM Australian Eastern time (Melbourne/Sydney) which is +1100 on Saturday the 5th of February.
I will start the video chat an hour early in case someone makes a timezone mistake and gets there an hour before it starts. If anyone else joins early we will have random chat until the start time (deliberately avoiding topics worthy of the main meeting). The link http://b.coker.com.au will redirect to the meeting URL on the day.
The first scheduled talk is a summary and discussion of free software related news. Anyone who knows of something new that excites them is welcome to speak about it.
The main event is discussion of storage technology and hands-on training on BTRFS and ZFS for those who are interested. Here are the ZFS training notes and here are the BTRFS training notes. Feel free to do the training exercises on your own VM before the meeting if you wish.
Then discussion of the future of the group and the use of FOSS social media. While social media is never going to be compulsory some people will want to use it to communicate and we could run some servers for software that is considered good (lots of server capacity is available).
Finally we have to plan future meetings and decide on which communication methods are desired.
The BBB instance to be used for the video conference is sponsored by NZOSS and Catalyst Cloud.
Since PM Scott Morrison did not announce the federal election date last week, it will now be held somewhere between March and May (see the post from ABC’s Antony Green for details). Various aspects of elections are covered in the Civics & Citizenship Australian Curriculum in Years 4, 5 and 6. Students are interested in […]
The main aim is to provide educational benefits to free software users via an online meeting that can’t be obtained by watching YouTube videos etc in a scope that is larger than one country. When the pandemic ends we will keep running this as there are benefits to be obtained from a meeting of a wide geographic scope that can’t be obtained by meetings in a single city. People from other countries are welcome to attend but they aren’t the focus of the meeting.
Until we get a better DNS name the address http://b.coker.com.au will redirect to the BBB instance used for online meetings (the meeting address isn’t yet setup so it redirects to the blog). The aim is that there will always be a short URL for the meeting so anyone who has one device lose contact can quickly type the URL into their backup device.
The first meeting will be on the 5th of Feb 2022 at 1PM Melbourne time +1100. When we get a proper domain I’ll publish a URL for an iCal file with entries for all meetings. I will also find some suitable way for meeting times to be localised (I’m sure there’s a WordPress plugin for that).
For the hands-on part of the meetings there will be virtual machine images you can download to run on your own system (tested with KVM, should work with other VM systems) and the possibility of logging in to a running VM. The demonstration VMs will have public IPv6 addresses and will also be available through different ports on a single IPv4 address, having IPv6 on your workstation will be convenient for you but you can survive without it.
Linux Australia has a list of LUGs in Australia, is there a similar list for NZ? One thing I’d like to see is a list of links for iCal files for all the meetings and also an iCal aggregator that for all iCal feeds of online meetings. I’ll host it myself if necessary, but it’s probably best to do it via Linux Australia (Linux Australasia?) if possible.
I’m attending the https://linux.conf.au/ conference online this weekend, which is always a good opportunity for some sideline hacking.
I found something boneheaded doing that today.
There have been a few times while inventing the OpenHMD Rift driver where I’ve noticed something strange and followed the thread until it made sense. Sometimes that leads to improvements in the driver, sometimes not.
In this case, I wanted to generate a graph of how long the computer vision processing takes – from the moment each camera frame is captured until poses are generated for each device.
To do that, I have a some logging branches that output JSON events to log files and I write scripts to process those. I used that data and produced:
Two things caught my eye in this graph. The first is the way the baseline latency (pink lines) increases from ~20ms to ~58ms. The 2nd is the quantisation effect, where pose latencies are clearly moving in discrete steps.
Neither of those should be happening.
Camera frames are being captured from the CV1 sensors every 19.2ms, and it takes that 17-18ms for them to be delivered across the USB. Depending on how many IR sources the cameras can see, figuring out the device poses can take a different amount of time, but the baseline should always hover around 17-18ms because the fast “device tracking locked” case take as little as 1ms.
Did you see me mention 19.2ms as the interframe period? Guess what the spacing on those quantisation levels are in the graph? I recognised it as implying that something in the processing is tied to frame timing when it should not be.
OpenHMD Rift CV1 tracking timing
This 2nd graph helped me pinpoint what exactly was going on. This graph is cut from the part of the session where the latency has jumped up. What it shows is a ~1 frame delay between when the frame is received (frame-arrival-finish-local-ts) before the initial analysis even starts!
That could imply that the analysis thread is just busy processing the previous frame and doesn’t get start working on the new one yet – but the graph says that fast analysis is typically done in 1-10ms at most. It should rarely be busy when the next frame arrives.
This is where I found the bone headed code – a rookie mistake I wrote when putting in place the image analysis threads early on in the driver development and never noticed.
There are 3 threads involved:
USB service thread, reading video frame packets and assembling pixels in framebuffers
Fast analysis thread, that checks tracking lock is still acquired
Long analysis thread, which does brute-force pose searching to reacquire / match unknown IR sources to device LEDs
These 3 threads communicate using frame worker queues passing frames between each other. Each analysis thread does this pseudocode:
while driver_running:
Pop a frame from the queue
Process the frame
Sleep for new frame notification
The problem is in the 3rd line. If the driver is ever still processing the frame in line 2 when a new frame arrives – say because the computer got really busy – the thread sleeps anyway and won’t wake up until the next frame arrives. At that point, there’ll be 2 frames in the queue, but it only still processes one – so the analysis gains a 1 frame latency from that point on. If it happens a second time, it gets later by another frame! Any further and it starts reclaiming frames from the queues to keep the video capture thread fed – but it only reclaims one frame at a time, so the latency remains!
The fix is simple:
while driver_running:
Pop a frame
Process the frame
if queue_is_empty():
sleep for new frame notification
Doing that for both the fast and long analysis threads changed the profile of the pose latency graph completely.
Pose latency and inter-pose spacing after fix
This is a massive win! To be clear, this has been causing problems in the driver for at least 18 months but was never obvious from the logs alone. A single good graph is worth a thousand logs.
What does this mean in practice?
The way the fusion filter I’ve built works, in between pose updates from the cameras, the position and orientation of each device are predicted / updated using the accelerometer and gyro readings. Particularly for position, using the IMU for prediction drifts fairly quickly. The longer the driver spends ‘coasting’ on the IMU, the less accurate the position tracking is. So, the sooner the driver can get a correction from the camera to the fusion filter the less drift we’ll get – especially under fast motion. Particularly for the hand controllers that get waved around.
Before: Left Controller pose delays by sensorAfter: Left Controller pose delays by sensor
Poses are now being updated up to 40ms earlier and the baseline is consistent with the USB transfer delay.
You can also visibly see the effect of the JPEG decoding support I added over Christmas. The ‘red’ camera is directly connected to USB3, while the ‘khaki’ camera is feeding JPEG frames over USB2 that then need to be decoded, adding a few ms delay.
The latency reduction is nicely visible in the pose graphs, where the ‘drop shadow’ effect of pose updates tailing fusion predictions largely disappears and there are fewer large gaps in the pose observations when long analysis happens (visible as straight lines jumping from point to point in the trace):
Before: Left Controller posesAfter: Left Controller poses
Yes, the blog is still on. January 2004 I moved to WordPress, and it is still here January 2022. I didn’t write much last year (neither here, not experimenting with the Hey blog). I didn’t post anything to Instagram last year either from what I can tell, just a lot of stories.
August 16 2021, I realised I was 1,000 days till May 12 2024, which is when I become 40. As of today, that leads 850 days. Did I squander the last 150 days? I’m back to writing almost daily in the Hobonichi Techo (I think last year and the year before were mostly washouts; I barely scribbled anything offline).
I got a new Apple Watch Series 7 yesterday. I can say I used the Series 4 well (79% battery life), purchased in the UK when I broke my Series 0 in Edinburgh airport.
TripIt stats for last year claimed 95 days on the road. This is of course, a massive joke, but I’m glad I did get to visit London, Lisbon, New York, San Francisco, Los Angeles without issue. I spent a lot of time in Kuantan, a bunch of Langkawi trips, and also, I stayed for many months at the Grand Hyatt Kuala Lumpur during the May lockdowns (I practically stayed there all lockdown).
With 850 days to go till I’m 40, I have plenty I would like to achieve. I think I’ll write a lot more here. And elsewhere. Get back into the habit of doing. And publishing by learning and doing. No fear. Not that I wasn’t doing, but its time to be prolific with what’s been going on.
Once again time has passed, and another update on Oculus Rift support feels due! As always, it feels like I’ve been busy with work and not found enough time for Rift CV1 hacking. Nevertheless, looking back over the history since I last wrote, there’s quite a lot to tell!
In general, the controller tracking is now really good most of the time. Like, wildly-swing-your-arms-and-not-lose-track levels (most of the time). The problems I’m hunting now are intermittent and hard to identify in the moment while using the headset – hence my enthusiasm over the last updates for implementing stream recording and a simulation setup. I’ll get back to that.
Outlier Detection
Since I last wrote, the tracking improvements have mostly come from identifying and rejecting incorrect measurements. That is, if I have 2 sensors active and 1 sensor says the left controller is in one place, but the 2nd sensor says it’s somewhere else, we’ll reject one of those – choosing the pose that best matches what we already know about the controller. The last known position, the gravity direction the IMU is detecting, and the last known orientation. The tracker will now also reject observations for a time if (for example) the reported orientation is outside the range we expect. The IMU gyroscope can track the orientation of a device for quite a while, so can be relied on to identify strong pose priors once we’ve integrated a few camera observations to get the yaw correct.
It works really well, but I think improving this area is still where most future refinements will come. That and avoiding incorrect pose extractions in the first place.
Plot of headset tracking – orientation and position
The above plot is a sample of headset tracking, showing the extracted poses from the computer vision vs the pose priors / tracking from the Kalman filter. As you can see, there are excursions in both position and orientation detected from the video, but these are largely ignored by the filter, producing a steadier result.
Left Touch controller tracking – orientation and position
This plot shows the left controller being tracked during a Beat Saber session. The controller tracking plot is quite different, because controllers move a lot more than the headset, and have fewer LEDs to track against. There are larger gaps here in the timeline while the vision re-acquires the device – and in those gaps you can see the Kalman filter interpolating using IMU input only (sometimes well, sometimes less so).
Improved Pose Priors
Another nice thing I did is changes in the way the search for a tracked device is made in a video frame. Before starting looking for a particular device it always now gets the latest estimate of the previous device position from the fusion filter. Previously, it would use the estimate of the device pose as it was when the camera exposure happened – but between then and the moment we start analysis more IMU observations and other camera observations might arrive and be integrated into the filter, which will have updated the estimate of where the device was in the frame.
This is the bit where I think the Kalman filter is particularly clever: Estimates of the device position at an earlier or later exposure can improve and refine the filter’s estimate of where the device was when the camera captured the frame we’re currently analysing! So clever. That mechanism (lagged state tracking) is what allows the filter to integrate past tracking observations once the analysis is done – so even if the video frame search take 150ms (for example), it will correct the filter’s estimate of where the device was 150ms in the past, which ripples through and corrects the estimate of where the device is now.
LED visibility model
To improve the identification of devices better, I measured the actual angle from which LEDs are visible (about 75 degrees off axis) and measured the size. The pose matching now has a better idea of which LEDs should be visible for a proposed orientation and what pixel size we expect them to have at a particular distance.
Better Smoothing
I fixed a bug in the output pose smoothing filter where it would glitch as you turned completely around and crossed the point where the angle jumps from +pi to -pi or vice versa.
Improved Display Distortion Correction
I got a wide-angle hi-res webcam and took photos of a checkerboard pattern through the lens of my headset, then used OpenCV and panotools to calculate new distortion and chromatic aberration parameters for the display. For me, this has greatly improved. I’m waiting to hear if that’s true for everyone, or if I’ve just fixed it for my headset.
Persistent Config Cache
Config blocks! A long time ago, I prototyped code to create a persistent OpenHMD configuration file store in ~/.config/openhmd. The rift-kalman-filter branch now uses that to store the configuration blocks that it reads from the controllers. The first time a controller is seen, it will load the JSON calibration block as before, but it will now store it in that directory – removing a multiple second radio read process on every subsequent startup.
Persistent Room Configuration
To go along with that, I have an experimental rift-room-config branch that creates a rift-room-config.json file and stores the camera positions after the first startup. I haven’t pushed that to the rift-kalman-filter branch yet, because I’m a bit worried it’ll cause surprising problems for people. If the initial estimate of the headset pose is wrong, the code will back-project the wrong positions for the cameras, which will get written to the file and cause every subsequent run of OpenHMD to generate bad tracking until the file is removed. The goal is to have a loop that monitors whether the camera positions seem stable based on the tracking reports, and to use averaging and resetting to correct them if not – or at least to warn the user that they should re-run some (non-existent) setup utility.
Video Capture + Processing
The final big ticket item was a rewrite of how the USB video frame capture thread collects pixels and passes them to the analysis threads. This now does less work in the USB thread, so misses fewer frames, and also I made it so that every frame is now searched for LEDs and blob identities tracked with motion vectors, even when no further analysis will be done on that frame. That means that when we’re running late, it better preserves LED blob identities until the analysis threads can catch up – increasing the chances of having known LEDs to directly find device positions and avoid searching. This rewrite also opened up a path to easily support JPEG decode – which is needed to support Rift Sensors connected on USB 2.0 ports.
Session Simulator
I mentioned the recording simulator continues to progress. Since the tracking problems are now getting really tricky to figure out, this tool is becoming increasingly important. So far, I have code in OpenHMD to record all video and tracking data to a .mkv file. Then, there’s a simulator tool that loads those recordings. Currently it is capable of extracting the data back out of the recording, parsing the JSON and decoding the video, and presenting it to a partially implemented simulator that then runs the same blob analysis and tracking OpenHMD does. The end goal is a Godot based visualiser for this simulation, and to be able to step back and forth through time examining what happened at critical moments so I can improve the tracking for those situations.
To make recordings, there’s the rift-debug-gstreamer-record branch of OpenHMD. If you have GStreamer and the right plugins (gst-plugins-good) installed, and you set env vars like this, each run of OpenHMD will generate a recording in the target directory (make sure the target dir exists):
The next things that are calling to me are to improve the room configuration estimation and storage as mentioned above – to detect when the poses a camera is reporting don’t make sense because it’s been bumped or moved.
I’d also like to add back in tracking of the LEDS on the back of the headset headband, to support 360 tracking. I disabled those because they cause me trouble – the headband is adjustable relative to the headset, so the LEDs don’t appear where the 3D model says they should be and that causes jitter and pose mismatches. They need special handling.
One last thing I’m finding exciting is a new person taking an interest in Rift S and starting to look at inside-out tracking for that. That’s just happened in the last few days, so not much to report yet – but I’ll be happy to have someone looking at that while I’m still busy over here in CV1 land!
As always, if you have any questions, comments or testing feedback – hit me up at thaytan@noraisin.net or on @thaytan Twitter/IRC.
Thank you to the kind people signed up as Github Sponsors for this project!
For a long time computer manufacturers have tried to differentiate themselves and their products from their competitors with fancy names with odd capitalisation and spelling. But as an author, using these names does a disservice to the reader: how are they to know that DEC is pronounced as if it was written Dec ("deck").
It's time we pushed back, and wrote for our readers, not for corporations.
It's time to use standard English rules for these Corporate Fancy Names. Proper names begin with a capital, unlike "ciscoSystems®" (so bad that Cisco itself moved away from it). Words are separated by spaces, so "Cisco Systems". Abbreviations and acronyms are written in lower case if they are pronounced as a word, in upper case if each letter is pronounced: so "ram" and "IBM®".
So from here on in I'll be using the following:
Face Book. Formerly, "Facebook®".
Junos. Formerly JUNOS®.
ram. Formerly RAM.
Pan OS. Formerly PAN-OS®.
Unix. Formerly UNIX®.
I'd encourage you to try this in your own writing. It does look odd for the first time, but the result is undeniably more readable. If we are not writing to be understood by our audience then we are nothing more than an unpaid member of some corporation's marketing team.
I gave the talk On The Use and Misuse of Decorators as part of PyConline AU 2021, the second in annoyingly long sequence of not-in-person PyCon AU events. Here’s some code samples that you might be interested in:
Simple @property implementation
This shows a demo of @property-style getters. Setters are left as an exercise :)
defdemo_property(f):f.is_a_property=TruereturnfclassHasProperties:def__getattribute__(self,name):ret=super().__getattribute__(name)ifhasattr(ret,"is_a_property"):returnret()else:returnretclassDemo(HasProperties):@demo_propertydefis_a_property(self):return"I'm a property"defis_a_function(self):return"I'm a function"a=Demo()print(a.is_a_function())print(a.is_a_property)
@run (The Scoped Block)
@run is a decorator that will run the body of the decorated function, and then store the result of that function in place of the function’s name. It makes it easier to assign the results of complex statements to a variable, and get the advantages of functions having less leaky scopes than if or loop blocks.
A while ago, I wrote a post about how to build and test my Oculus CV1 tracking code in SteamVR using the SteamVR-OpenHMD driver. I have updated those instructions and moved them to https://noraisin.net/diary/?page_id=1048 – so use those if you’d like to try things out.
The pandemic continues to sap my time for OpenHMD improvements. Since my last post, I have been working on various refinements. The biggest visible improvements are:
Adding velocity and acceleration API to OpenHMD.
Rewriting the pose transformation code that maps from the IMU-centric tracking space to the device pose needed by SteamVR / apps.
Adding velocity and acceleration reporting is needed in VR apps that support throwing things. It means that throwing objects and using gravity-grab to fetch objects works in Half-Life: Alyx, making it playable now.
The rewrite to the pose transformation code fixed problems where the rotation of controller models in VR didn’t match the rotation applied in the real world. Controllers would appear attached to the wrong part of the hand, and rotate around the wrong axis. Movements feel more natural now.
Ongoing work – record and replay
My focus going forward is on fixing glitches that are caused by tracking losses or outliers. Those problems happen when the computer vision code either fails to match what the cameras see to the device LED models, or when it matches incorrectly.
Tracking failure leads to the headset view or controllers ‘flying away’ suddenly. Incorrect matching leads to controllers jumping and jittering to the wrong pose, or swapping hands. Either condition is very annoying.
Unfortunately, as the tracking has improved the remaining problems get harder to understand and there is less low-hanging fruit for improvement. Further, when the computer vision runs at 52Hz, it’s impossible to diagnose the reasons for a glitch in real time.
I’ve built a branch of OpenHMD that uses GStreamer to record the CV1 camera video, plus IMU and tracking logs into a video file.
To go with those recordings, I’ve been working on a replay and simulation tool, that uses the Godot game engine to visualise the tracking session. The goal is to show, frame-by-frame, where OpenHMD thought the cameras, headset and controllers were at each point in the session, and to be able to step back and forth through the recording.
Right now, I’m working on the simulation portion of the replay, that will use the tracking logs to recreate all the poses.
GKE in Production - Part 2 This tutorial is part of a series I am creating on creating, running and managing Kubernetes on GCP the way I do in my day job. In this episode, we are covering how to setup a nginx ingress controller to handle incoming requests.
Note: There may be some things I have skimmed over, if so or you see a glaring hole in my configuration, please drop me a line via the contact page linked at the top of the site.
I’ve been asked more than once what it was like at the beginning of Ubuntu, before it was a company, when an email from someone I’d never heard of came into my mailbox.
We’re coming up on 20 years now since Ubuntu was founded, and I had cause to do some spelunking into IMAP archives recently… while there I took the opportunity to grab the very first email I received.
The Ubuntu long shot succeeded wildly. Of course, we liked to joke about how spammy those emails where: cold-calling a raft of Debian developers with job offers, some of them were closer to phishing attacks :). This very early one – I was the second employee (though I started at 4 days a week to transition my clients gradually) – was less so.
I think its interesting though to note how explicit a gamble this was framed as: a time limited experiment, funded for a year. As the company scaled this very rapidly became a hiring problem and the horizon had to be pushed out to 2 years to get folk to join.
And of course, while we started with arch in earnest, we rapidly hit significant usability problems, some of which were solvable with porcelain and shallow non-architectural changes, and we built initially patches, and then the bazaar VCS project to tackle those. But others were not: for instance, I recall exceeding the 32K hard link limit on ext3 due to a single long history during a VCS conversion. The sum of these challenges led us to create the bzr project, a ground up rethink of our version control needs, architecture, implementation and user-experience. While ultimately git has conquered all, bzr had – still has in fact – extremely loyal advocates, due to its laser sharp focus on usability.
Anyhow, here it is: one of the original no-name-here-yet, aka Ubuntu, introductory emails (with permission from Mark, of course). When I clicked through to the website Mark provided there was a link there to a fantastical website about a space tourist… not what I had expected to be reading in Adelaide during LCA 2004.
From: Mark Shuttleworth <xxx@xxx> To: Robert Collins <xxx@xxx> Date: Thu, 15 Jan 2004, 04:30
Tom Lord gave me your email address, I believe he’s already sent you the email that I sent him so I’m sure you have some background.
In short, I am going to fund some open source development for a year. This is part of a new project that I will be getting off the ground in the coming weeks. I don’t know where it will lead, it’s flying in the face of a stiff breeze but I think at the end of the day it will at least fund a few very good open source developers for a full year to work on the projects they like most.
One of the pieces of the puzzle is high end source code management. I’ll be looking to build an infrastructure that will manage source code for between 100 and 8000 open source projects (yes, there’s a big difference between the two, I don’t know at which end of the spectrum we will be at the end of the year but our infrastructure will have to at least be capable of scaling to the latter within two years) with upwards of 2000 developers, drawing code from a variety of sources, playing with it and spitting it out regularly in nice packages.
Arch and Subversion seem to be the two leading contenders for “next generation open source sccm”. I’d be interested in your thoughts on the two of them, and how they stack up. I’m looking to hire one person who will lead that part of the effort. They’ll work alone from home, and be responsible for two things. First, extending the tool (arch or svn) in ways that help the project. Such extensions will be released under an open source licence, and hopefully embraced by the tools maintainers and included in the mainline code for the tool. And second, they will be responsible for our large-scale implementation of SCCM, using that tool, and building the management scripts and other infrastructure to support such a large, and hopefully highly automated, set of repositories.
Would you be interested in this position? What attributes and experience do you think would make you a great person to have on the team? What would your salary expectation be, as a monthly figure, for a one year contract full time?
I’m currently on your continent, well, just off it. On Lizard Island, up North. Am headed today for Brisbane, then on the 17th to Launceston via Melbourne. If you happen to be on any of those stops, would you be interested in meeting up to discuss it further?
If you’re curious you can find out a bit more about me at www.markshuttleworth.com. This project is much lower key than some of what you’ll find there. It’s a very long shot indeed. But if at worst all that happens is a bunch of open source work gets funded at my expense I’ll feel it was money well spent.
Cheers, Mark
===== — “Good judgement comes from experience, and often experience comes from bad judgement” – Rita Mae Brown
I have always liked cryptography, and public-key cryptography in particularly. When Pretty Good Privacy (PGP) first came out in 1991, I not only started using it, also but looking at the documentation and the code to see how it worked. I created my own implementation in C using very small keys, just to better understand.
Cryptography has been running a race against both faster and cheaper computing power. And these days, with banking and most other aspects of our lives entirely relying on secure communications, it’s a very juicy target for bad actors.
About 5 years ago, the National (USA) Institute for Science and Technology (NIST) initiated a search for cryptographic algorithmic that should withstand a near-future world where quantum computers with a significant number of qubits are a reality. There have been a number of rounds, which mid 2020 saw round 3 and the finalists.
This submission caught my eye some time ago: Classic McEliece, and out of the four finalists it’s the only one that is not lattice-based [wikipedia link].
Tiny side-track, you may wonder where does the McEleice name come from? From mathematician Robert McEleice (1942-2019). McEleice developed his cryptosystem in 1978. So it’s not just named after him, he designed it. For various reasons that have nothing to do with the mathematical solidity of the ideas, it didn’t get used at the time. He’s done plenty cool other things, too. From his Caltech obituary:
He made fundamental contributions to the theory and design of channel codes for communication systems—including the interplanetary telecommunication systems that were used by the Voyager, Galileo, Mars Pathfinder, Cassini, and Mars Exploration Rover missions.
Back to lattices, there are both unknowns (aspects that have not been studied in exhaustive depth) and recent mathematical attacks, both of which create uncertainty – in the crypto sphere as well as for business and politics. Given how long it takes for crypto schemes to get widely adopted, the latter two are somewhat relevant, particularly since cyber security is a hot topic.
Lattices are definitely interesting, but given what we know so far, it is my feeling that systems based on lattices are more likely to be proven breakable than Classic McEleice, which come to this finalists’ table with 40+ years track record of in-depth analysis. Mind that all finalists are of course solid at this stage – but NIST’s thoughts on expected developments and breakthroughs is what is likely to decide the winner. NIST are not looking for shiny, they are looking for very very solid in all possible ways.
Prof Buchanan recently published implementations for the finalists, and did some benchmarks where we can directly compare them against each other.
We can see that Classic McEleice’s key generation is CPU intensive, but is that really a problem? The large size of its public key may be more of a factor (disadvantage), however the small ciphertext I think more than offsets that disadvantage.
As we’re nearing the end of the NIST process, in my opinion, fast encryption/decryption and small cyphertext, combined with the long track record of in-depth analysis, may still see Classic McEleice come out the winner.
GKE in Production - Part 1 This tutorial is part of a series I am creating on creating, running and managing Kubernetes on GCP the way I do in my day job.
Note: There may be some things I have skimmed over, if so or you see a glaring hole in my configuration, please drop me a line via the contact page linked at the top of the site.
What we will build In this first tutorial, we will be building a standard GKE cluster on Google Cloud Platform and deploying the hello world container to confirm everything is working.
Living in California, I’ve (sadly) grown accustomed to needing to keep track of our local air quality index (AQI) ratings, particularly as we live close to places where large wildfires happen every other year.
Last year, Josh and I bought a PurpleAir outdoor air quality meter, which has been great. We contribute our data to a collection of very local air quality meters, which is important, since the hilly nature of the North Bay means that the nearest government air quality ratings can be significantly different to what we experience here in Petaluma.
I recently went looking to pull my PurpleAir sensor data into my Home Assistant setup. Unfortunately, the PurpleAir API does not return the AQI metric for air quality, only the raw PM2.5/PM5/PM10 numbers. After some searching, I found a nice template sensor solution on the Home Assistant forums, which I’ve modernised by adding the AQI as a sub-sensor, and adding unique ID fields to each useful sensor, so that you can assign them to a location.
You’ll end up with sensors for raw PM2.5, the PM2.5 AQI value, the US EPA air quality category, air pressure, relative humidity and air pressure.
How to use this
First up, visit the PurpleAir Map, find the sensor you care about, click “get this widget�, and then “JSON�. That will give you the URL to set as the resource key in purpleair.yaml.
Adding the configuration
In HomeAssistant, add the following line to your configuration.yaml:
sensor:!includepurpleair.yaml
and then add the following contents to purpleair.yaml
-platform:restname:'PurpleAir'# Substitute in the URL of the sensor you care about. To find the URL, go# to purpleair.com/map, find your sensor, click on it, click on "Get This# Widget" then click on "JSON".resource:https://www.purpleair.com/json?key={KEY_GOES_HERE}&show={SENSOR_ID}# Only query once a minute to avoid rate limits:scan_interval:60# Set this sensor to be the AQI value.## Code translated from JavaScript found at:# https://docs.google.com/document/d/15ijz94dXJ-YAZLi9iZ_RaBwrZ4KtYeCy08goGBwnbCU/edit#value_template:>{{ value_json["results"][0]["Label"] }}unit_of_measurement:""# The value of the sensor can't be longer than 255 characters, but the# attributes can. Store away all the data for use by the templates below.json_attributes:-results-platform:templatesensors:purpleair_aqi:unique_id:'purpleair_SENSORID_aqi_pm25'friendly_name:'PurpleAirPM2.5AQI'value_template:>{% macro calcAQI(Cp, Ih, Il, BPh, BPl) -%}{{ (((Ih - Il)/(BPh - BPl)) * (Cp - BPl) + Il)|round|float }}{%- endmacro %}{% if (states('sensor.purpleair_pm25')|float) > 1000 %}invalid{% elif (states('sensor.purpleair_pm25')|float) > 350.5 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 500.0, 401.0, 500.0, 350.5) }}{% elif (states('sensor.purpleair_pm25')|float) > 250.5 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 400.0, 301.0, 350.4, 250.5) }}{% elif (states('sensor.purpleair_pm25')|float) > 150.5 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 300.0, 201.0, 250.4, 150.5) }}{% elif (states('sensor.purpleair_pm25')|float) > 55.5 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 200.0, 151.0, 150.4, 55.5) }}{% elif (states('sensor.purpleair_pm25')|float) > 35.5 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 150.0, 101.0, 55.4, 35.5) }}{% elif (states('sensor.purpleair_pm25')|float) > 12.1 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 100.0, 51.0, 35.4, 12.1) }}{% elif (states('sensor.purpleair_pm25')|float) >= 0.0 %}{{ calcAQI((states('sensor.purpleair_pm25')|float), 50.0, 0.0, 12.0, 0.0) }}{% else %}invalid{% endif %}unit_of_measurement:"bit"purpleair_description:unique_id:'purpleair_SENSORID_description'friendly_name:'PurpleAirAQIDescription'value_template:>{% if (states('sensor.purpleair_aqi')|float) >= 401.0 %}Hazardous{% elif (states('sensor.purpleair_aqi')|float) >= 301.0 %}Hazardous{% elif (states('sensor.purpleair_aqi')|float) >= 201.0 %}Very Unhealthy{% elif (states('sensor.purpleair_aqi')|float) >= 151.0 %}Unhealthy{% elif (states('sensor.purpleair_aqi')|float) >= 101.0 %}Unhealthy for Sensitive Groups{% elif (states('sensor.purpleair_aqi')|float) >= 51.0 %}Moderate{% elif (states('sensor.purpleair_aqi')|float) >= 0.0 %}Good{% else %}undefined{% endif %}entity_id:sensor.purpleairpurpleair_pm25:unique_id:'purpleair_SENSORID_pm25'friendly_name:'PurpleAirPM2.5'value_template:"{{state_attr('sensor.purpleair','results')[0]['PM2_5Value']}}"unit_of_measurement:"μg/m3"entity_id:sensor.purpleairpurpleair_temp:unique_id:'purpleair_SENSORID_temperature'friendly_name:'PurpleAirTemperature'value_template:"{{state_attr('sensor.purpleair','results')[0]['temp_f']}}"unit_of_measurement:"°F"entity_id:sensor.purpleairpurpleair_humidity:unique_id:'purpleair_SENSORID_humidity'friendly_name:'PurpleAirHumidity'value_template:"{{state_attr('sensor.purpleair','results')[0]['humidity']}}"unit_of_measurement:"%"entity_id:sensor.purpleairpurpleair_pressure:unique_id:'purpleair_SENSORID_pressure'friendly_name:'PurpleAirPressure'value_template:"{{state_attr('sensor.purpleair','results')[0]['pressure']}}"unit_of_measurement:"hPa"entity_id:sensor.purpleair
Quirks
I had difficulty getting the AQI to display as a numeric graph when I didn’t set a unit. I went with bit, and that worked just fine. 🤷�♂�
So, this idea has been brewing for a while now… try and watch all of Doctor Who. All of it. All 38 seasons. Today(ish), we started. First up, from 1963 (first aired not quite when intended due to the Kennedy assassination): An Unearthly Child. The first episode of the first serial.
A lot of iconic things are there from the start: the music, the Police Box, embarrassing moments of not quite remembering what time one is in, and normal humans accidentally finding their way into the TARDIS.
I first saw this way back when a child, where they were repeated on ABC TV in Australia for some anniversary of Doctor Who (I forget which one). Well, I saw all but the first episode as the train home was delayed and stopped outside Caulfield for no reason for ages. Some things never change.
Of course, being a show from the early 1960s, there’s some rougher spots. We’re not about to have the picture of diversity, and there’s going to be casual racism and sexism. What will be interesting is noticing these things today, and contrasting with my memory of them at the time (at least for episodes I’ve seen before), and what I know of the attitudes of the time.
“This year-ometer is not calculating properly” is a very 2020 line though (technically from the second episode).
It’s been a while since my last post about tracking support for the Oculus Rift in February. There’s been big improvements since then – working really well a lot of the time. It’s gone from “If I don’t make any sudden moves, I can finish an easy Beat Saber level” to “You can’t hide from me!” quality.
Equally, there are still enough glitches and corner cases that I think I’ll still be at this a while.
Here’s a video from 3 weeks ago of (not me) playing Beat Saber on Expert+ setting showing just how good things can be now:
Beat Saber – Skunkynator playing Expert+, Mar 16 2021
Strap in. Here’s what I’ve worked on in the last 6 weeks:
Pose Matching improvements
Most of the biggest improvements have come from improving the computer vision algorithm that’s matching the observed LEDs (blobs) in the camera frames to the 3D models of the devices.
I split the brute-force search algorithm into 2 phases. It now does a first pass looking for ‘obvious’ matches. In that pass, it does a shallow graph search of blobs and their nearest few neighbours against LEDs and their nearest neighbours, looking for a match using a “Strong” match metric. A match is considered strong if expected LEDs match observed blobs to within 1.5 pixels.
Coupled with checks on the expected orientation (matching the Gravity vector detected by the IMU) and the pose prior (expected position and orientation are within predicted error bounds) this short-circuit on the search is hit a lot of the time, and often completes within 1 frame duration.
In the remaining tricky cases, where a deeper graph search is required in order to recover the pose, the initial search reduces the number of LEDs and blobs under consideration, speeding up the remaining search.
I also added an LED size model to the mix – for a candidate pose, it tries to work out how large (in pixels) each LED should appear, and use that as a bound on matching blobs to LEDs. This helps reduce mismatches as devices move further from the camera.
LED labelling
When a brute-force search for pose recovery completes, the system now knows the identity of various blobs in the camera image. One way it avoids a search next time is to transfer the labels into future camera observations using optical-flow tracking on the visible blobs.
The problem is that even sped-up the search can still take a few frame-durations to complete. Previously LED labels would be transferred from frame to frame as they arrived, but there’s now a unique ID associated with each blob that allows the labels to be transferred even several frames later once their identity is known.
IMU Gyro scale
One of the problems with reverse engineering is the guesswork around exactly what different values mean. I was looking into why the controller movement felt “swimmy” under fast motions, and one thing I found was that the interpretation of the gyroscope readings from the IMU was incorrect.
The touch controllers report IMU angular velocity readings directly as a 16-bit signed integer. Previously the code would take the reading and divide by 1024 and use the value as radians/second.
From teardowns of the controller, I know the IMU is an Invensense MPU-6500. From the datasheet, the reported value is actually in degrees per second and appears to be configured for the +/- 2000 °/s range. That yields a calculation of Gyro-rad/s = Gyro-°/s * (2000 / 32768) * (?/180) – or a divisor of 938.734.
The 1024 divisor was under-estimating rotation speed by about 10% – close enough to work until you start moving quickly.
Limited interpolation
If we don’t find a device in the camera views, the fusion filter predicts motion using the IMU readings – but that quickly becomes inaccurate. In the worst case, the controllers fly off into the distance. To avoid that, I added a limit of 500ms for ‘coasting’. If we haven’t recovered the device pose by then, the position is frozen in place and only rotation is updated until the cameras find it again.
Exponential filtering
I implemented a 1-Euro exponential smoothing filter on the output poses for each device. This is an idea from the Project Esky driver for Project North Star/Deck-X AR headsets, and almost completely eliminates jitter in the headset view and hand controllers shown to the user. The tradeoff is against introducing lag when the user moves quickly – but there are some tunables in the exponential filter to play with for minimising that. For now I’ve picked some values that seem to work reasonably.
Non-blocking radio
Communications with the touch controllers happens through USB radio command packets sent to the headset. The main use of radio commands in OpenHMD is to read the JSON configuration block for each controller that is programmed in at the factory. The configuration block provides the 3D model of LED positions as well as initial IMU bias values.
Unfortunately, reading the configuration block takes a couple of seconds on startup, and blocks everything while it’s happening. Oculus saw that problem and added a checksum in the controller firmware. You can read the checksum first and if it hasn’t changed use a local cache of the configuration block. Eventually, I’ll implement that caching mechanism for OpenHMD but in the meantime it still reads the configuration blocks on each startup.
As an interim improvement I rewrote the radio communication logic to use a state machine that is checked in the update loop – allowing radio communications to be interleaved without blocking the regularly processing of events. It still interferes a bit, but no longer causes a full multi-second stall as each hand controller turns on.
Haptic feedback
The hand controllers have haptic feedback ‘rumble’ motors that really add to the immersiveness of VR by letting you sense collisions with objects. Until now, OpenHMD hasn’t had any support for applications to trigger haptic events. I spent a bit of time looking at USB packet traces with Philipp Zabel and we figured out the radio commands to turn the rumble motors on and off.
In the Rift CV1, the haptic motors have a mode where you schedule feedback events into a ringbuffer – effectively they operate like a low frequency audio device. However, that mode was removed for the Rift S (and presumably in the Quest devices) – and deprecated for the CV1.
With that in mind, I aimed for implementing the unbuffered mode, with explicit ‘motor on + frequency + amplitude’ and ‘motor off’ commands sent as needed. Thanks to already having rewritten the radio communications to use a state machine, adding haptic commands was fairly easy.
I’d say the biggest problem right now is unexpected tracking loss and incorrect pose extractions when I’m not expecting them. Especially my right controller will suddenly glitch and start jumping around. Looking at a video of the debug feed, it’s not obvious why that’s happening:
To fix cases like those, I plan to add code to log the raw video feed and the IMU information together so that I can replay the video analysis frame-by-frame and investigate glitches systematically. Those recordings will also work as a regression suite to test future changes.
Sensor fusion efficiency
The Kalman filter I have implemented works really nicely – it does the latency compensation, predicts motion and extracts sensor biases all in one place… but it has a big downside of being quite expensive in CPU. The Unscented Kalman Filter CPU cost grows at O(n^3) with the size of the state, and the state in this case is 43 dimensional – 22 base dimensions, and 7 per latency-compensation slot. Running 1000 updates per second for the HMD and 500 for each of the hand controllers adds up quickly.
At some point, I want to find a better / cheaper approach to the problem that still provides low-latency motion predictions for the user while still providing the same benefits around latency compensation and bias extraction.
Lens Distortion
To generate a convincing illusion of objects at a distance in a headset that’s only a few centimetres deep, VR headsets use some interesting optics. The LCD/OLED panels displaying the output get distorted heavily before they hit the users eyes. What the software generates needs to compensate by applying the right inverse distortion to the output video.
Everyone that tests the CV1 notices that the distortion is not quite correct. As you look around, the world warps and shifts annoyingly. Sooner or later that needs fixing. That’s done by taking photos of calibration patterns through the headset lenses and generating a distortion model.
Camera / USB failures
The camera feeds are captured using a custom user-space UVC driver implementation that knows how to set up the special synchronisation settings of the CV1 and DK2 cameras, and then repeatedly schedules isochronous USB packet transfers to receive the video.
Occasionally, some people experience failure to re-schedule those transfers. The kernel rejects them with an out-of-memory error failing to set aside DMA memory (even though it may have been running fine for quite some time). It’s not clear why that happens – but the end result at the moment is that the USB traffic for that camera dies completely and there’ll be no more tracking from that camera until the application is restarted.
Often once it starts happening, it will keep happening until the PC is rebooted and the kernel memory state is reset.
Occluded cases
Tracking generally works well when the cameras get a clear shot of each device, but there are cases like sighting down the barrel of a gun where we expect that the user will line up the controllers in front of one another, and in front of the headset. In that case, even though we probably have a good idea where each device is, it can be hard to figure out which LEDs belong to which device.
If we already have a good tracking lock on the devices, I think it should be possible to keep tracking even down to 1 or 2 LEDs being visible – but the pose assessment code will have to be aware that’s what is happening.
Upstreaming
April 14th marks 2 years since I first branched off OpenHMD master to start working on CV1 tracking. How hard can it be, I thought? I’ll knock this over in a few months.
Since then I’ve accumulated over 300 commits on top of OpenHMD master that eventually all need upstreaming in some way.
One thing people have expressed as a prerequisite for upstreaming is to try and remove the OpenCV dependency. The tracking relies on OpenCV to do camera distortion calculations, and for their PnP implementation. It should be possible to reimplement both of those directly in OpenHMD with a bit of work – possibly using the fast LambdaTwist P3P algorithm that Philipp Zabel wrote, that I’m already using for pose extraction in the brute-force search.
Others
I’ve picked the top issues to highlight here. https://github.com/thaytan/OpenHMD/issues has a list of all the other things that are still on the radar for fixing eventually.
Other Headsets
At some point soon, I plan to put a pin in the CV1 tracking and look at adapting it to more recent inside-out headsets like the Rift S and WMR headsets. I implemented 3DOF support for the Rift S last year, but getting to full positional tracking for that and other inside-out headsets means implementing a SLAM/VIO tracking algorithm to track the headset position.
Once the headset is tracking, the code I’m developing here for CV1 to find and track controllers will hopefully transfer across – the difference with inside-out tracking is that the cameras move around with the headset. Finding the controllers in the actual video feed should work much the same.
Sponsorship
This development happens mostly in my spare time and partly as open source contribution time at work at Centricular. I am accepting funding through Github Sponsorships to help me spend more time on it – I’d really like to keep helping Linux have top-notch support for VR/AR applications. Big thanks to the people that have helped get this far.
Why that particular date? It’s Vincent van Gogh’s birthday (1853), and there is a fairly strong argument that the Dutch painter suffered from bipolar (among other things).
The image on the side is Vincent’s drawing “Worn Out” (from 1882), and it seems to capture the feeling rather well – whether (hypo)manic, depressed, or mixed. It’s exhausting.
Bipolar is complicated, often undiagnosed or misdiagnosed, and when only treated with anti-depressants, it can trigger the (hypo)mania – essentially dragging that person into that state near-permanently.
Have you heard of Bipolar II?
Hypo-mania is the “lesser” form of mania that distinguishes Bipolar I (the classic “manic depressive” syndrome) from Bipolar II. It’s “lesser” only in the sense that rather than someone going so hyper they may think they can fly (Bipolar I is often identified when someone in manic state gets admitted to hospital – good catch!) while with Bipolar II the hypo-mania may actually exhibit as anger. Anger in general, against nothing in particular but potentially everyone and everything around them. Or, if it’s a mixed episode, anger combined with strong negative thoughts. Either way, it does not look like classic mania. It is, however, exhausting and can be very debilitating.
Bipolar II people often present to a doctor while in depressed state, and GPs (not being psychiatrists) may not do a full diagnosis. Note that D.A.S. and similar test sheets are screening tools, they are not diagnostic. A proper diagnosis is more complex than filling in a form some questions (who would have thought!)
Call to action
If you have a diagnosis of depression, only from a GP, and are on medication for this, I would strongly recommend you also get a referral to a psychiatrist to confirm that diagnosis.
Our friends at the awesome Black Dog Institute have excellent information on bipolar, as well as a quick self-test – if that shows some likelihood of bipolar, go get that referral and follow up ASAP.
I will be writing more about the topic in the coming time.
This post documented an older method of building SteamVR-OpenHMD. I moved them to a page here. That version will be kept up to date for any future changes, so go there.
I’ve had a few people ask how to test my OpenHMD development branch of Rift CV1 positional tracking in SteamVR. Here’s what I do:
It is important to configure in release mode, as the kalman filtering code is generally too slow for real-time in debug mode (it has to run 2000 times per second)
Please note – only Rift sensors on USB 3.0 ports will work right now. Supporting cameras on USB 2.0 requires someone implementing JPEG format streaming and decoding.
It can be helpful to test OpenHMD is working by running the simple example. Check that it’s finding camera sensors at startup, and that the position seems to change when you move the headset:
Calibrate your expectations for how well tracking is working right now! Hint: It’s very experimental
Start SteamVR. Hopefully it should detect your headset and the light(s) on your Rift Sensor(s) should power on.
Meson
I prefer the Meson build system here. There’s also a cmake build for SteamVR-OpenHMD you can use instead, but I haven’t tested it in a while and it sometimes breaks as I work on my development branch.
I spent some time this weekend implementing a couple of my ideas for improving the way the tracking code in OpenHMD filters and rejects (or accepts) possible poses when trying to match visible LEDs to the 3D models for each device.
In general, the tracking proceeds in several steps (in parallel for each of the 3 devices being tracked):
Do a brute-force search to match LEDs to 3D models, then (if matched)
Assign labels to each LED blob in the video frame saying what LED they are.
Send an update to the fusion filter about the position / orientation of the device
Then, as each video frame arrives:
Use motion flow between video frames to track the movement of each visible LED
Use the IMU + vision fusion filter to predict the position/orientation (pose) of each device, and calculate which LEDs are expected to be visible and where.
Try and match up and refine the poses using the predicted pose prior and labelled LEDs. In the best case, the LEDs are exactly where the fusion predicts they’ll be. More often, the orientation is mostly correct, but the position has drifted and needs correcting. In the worst case, we send the frame back to step 1 and do a brute-force search to reacquire an object.
The goal is to always assign the correct LEDs to the correct device (so you don’t end up with the right controller in your left hand), and to avoid going back to the expensive brute-force search to re-acquire devices as much as possible
What I’ve been working on this week is steps 1 and 3 – initial acquisition of correct poses, and fast validation / refinement of the pose in each video frame, and I’ve implemented two new strategies for that.
Gravity Vector matching
The first new strategy is to reject candidate poses that don’t closely match the known direction of gravity for each device. I had a previous implementation of that idea which turned out to be wrong, so I’ve re-worked it and it helps a lot with device acquisition.
The IMU accelerometer and gyro can usually tell us which way up the device is (roll and pitch) but not which way they are facing (yaw). The measure for ‘known gravity’ comes from the fusion Kalman filter covariance matrix – how certain the filter is about the orientation of the device. If that variance is small this new strategy is used to reject possible poses that don’t have the same idea of gravity (while permitting rotations around the Y axis), with the filter variance as a tolerance.
Partial tracking matches
The 2nd strategy is based around tracking with fewer LED correspondences once a tracking lock is acquired. Initial acquisition of the device pose relies on some heuristics for how many LEDs must match the 3D model. The general heuristic threshold I settled on for now is that 2/3rds of the expected LEDs must be visible to acquire a cold lock.
With the new strategy, if the pose prior has a good idea where the device is and which way it’s facing, it allows matching on far fewer LED correspondences. The idea is to keep tracking a device even down to just a couple of LEDs, and hope that more become visible soon.
While this definitely seems to help, I think the approach can use more work.
Status
With these two new approaches, tracking is improved but still quite erratic. Tracking of the headset itself is quite good now and for me rarely loses tracking lock. The controllers are better, but have a tendency to “fly off my hands” unexpectedly, especially after fast motions.
I have ideas for more tracking heuristics to implement, and I expect a continuous cycle of refinement on the existing strategies and new ones for some time to come.
For now, here’s a video of me playing Beat Saber using tonight’s code. The video shows the debug stream that OpenHMD can generate via Pipewire, showing the camera feed plus overlays of device predictions, LED device assignments and tracked device positions. Red is the headset, Green is the right controller, Blue is the left controller.
Initial tracking is completely wrong – I see some things to fix there. When the controllers go offline due to inactivity, the code keeps trying to match LEDs to them for example, and then there are some things wrong with how it’s relabelling LEDs when they get incorrect assignments.
After that, there are periods of good tracking with random tracking losses on the controllers – those show the problem cases to concentrate on.
These lack of updates are also likely because I’ve been quite caught up with stuff.
Monday I had a steak from Bay Leaf Steakhouse for dinner. It was kind of weird eating it from packs, but then I’m reminded you could do this in economy class. Tuesday I wanted to attempt to go vegetarian and by the time I was done with a workout, the only place was a chap fan shop (Leong Heng) where I had a mixture of Chinese and Indian chap fan. The Indian stall is run by an ex-Hyatt staff member who immediately recognised me! Wednesday, Alice came to visit, so we got to Hanks, got some alcohol, and managed a smorgasbord of food from Pickers/Sate Zul/Lila Wadi. Night ended very late, and on Thursday, visited Hai Tian for their famous salted egg squid and prawns in a coconut shell. Friday was back to being normal, so I grabbed a pizza from Mint Pizza (this time I tried their Aussie variant). Saturday, today, I hit up Rasa Sayang for some matcha latte, but grabbed food from Classic Pilot Cafe, which Faeeza owns! It was the famous salted egg chicken, double portion, half rice.
As for workouts, I did sign up for Mantas but found it pretty hard to do, timezone wise. I did spend a lot of time jogging on the beach (this has been almost a daily affair). Monday I also did 2 MD workouts, Tuesday 1 MD workout, Wednesday half a MD workout, Thursday I did a Ping workout at Pwrhouse (so good!), Friday 1 MD workout, and Saturday an Audrey workout at Pwrhouse and 1 MD workout.
Wednesday I also found out that Rasmus passed away. Frankly, there are no words.
Thursday, my Raspberry Pi 400 arrived. I set it up in under ten minutes, connecting it to the TV here. It “just works”. I made a video, which I should probably figure out how to upload to YouTube after I stitch it together. I have to work on using it a lot more.
COVID-19 cases are through the roof in Malaysia. This weekend we’ve seen two days of case breaking records, with today being 5,728 (yesterday was something close). Nutty. Singapore suspended the reciprocal green lane (RGL) agreement with Malaysia for the next 3 months.
I’ve managed to finish Bridgerton. I like the score. Finding something on Netflix is proving to be more difficult, regardless of having a VPN. Honestly, this is why Cable TV wins… linear programming that you’re just fed.
Stock market wise, I’ve been following the GameStop short squeeze, and even funnier is the Top Glove one, that they’re trying to repeat in Malaysia. Bitcoin seems to be doing “reasonably well” and I have to say, I think people are starting to realise decentralised services have a future. How do we get there?
What an interesting week, I look forward to more productive time. I’m still writing in my Hobonichi Techo, so at least that’s where most personal stuff ends up, I guess?
I hit an important OpenHMD milestone tonight – I completed a Beat Saber level using my Oculus Rift CV1!
I’ve been continuing to work on integrating Kalman filtering into OpenHMD, and on improving the computer vision that matches and tracks device LEDs. While I suspect noone will be completing Expert levels just yet, it’s working well enough that I was able to play through a complete level of Beat Saber. For a long time this has been my mental benchmark for tracking performance, and I’m really happy
Check it out:
I should admit at this point that completing this level took me multiple attempts. The tracking still has quite a tendency to lose track of controllers, or to get them confused and swap hands suddenly.
I have a list of more things to work on. See you at the next update!
What an unplanned day. I woke up in time to do an MD workout, despite feeling a little sore. So maybe I was about 10 minutes late and I missed the first set, but his workouts are so long, and I think there were seven sets anyway. Had a good brunch shortly thereafter.
Did a bit of reading, and then I decided to do a beach boardwalk walk… turns out they were policing the place, and you can’t hit the boardwalk. But the beach is fair game? So I went back to the hotel, dropped off my slippers, and went for a beach jog. Pretty nutty.
Came back to read a little more and figured I might as well do another MD workout. Then I headed out for dinner, trying out a new place — Mint Pizza. Opened 20.12.2020, and they’re empty, and their pizza is actually pretty good. Lamb and BBQ chicken, they did half-and-half.
Twitter was discussing Raspberry Pi’s, and all I could see is a lot of misinformation, which is truly shocking. The irony is that open source has been running the Internet for so long, and progressive web apps have come such a long way…
Learn concepts, not tools.
One ensures lifelong flexibility, the other has potential for obsolescence.
Your knowledge of doing a mail merge will spread from Word, to Pages, to Writer or Docs.
Back in the day when I did OpenOffice.org or Linux training even, we always did say you should learn concepts and not tools. From the time we ran Linux installfests in the late-90s in Sunway Pyramid (back then, yes, Linux was hard, and you had winmodems), but I had forgotten that I even did stuff for school teachers and NGOs back in 2002… I won’t forget PC Gemilang either…
Anyway, I placed an order again for another Raspberry Pi 400. I am certain that most people talk so much crap, without realising that Malaysia isn’t a developed nation and most people can’t afford a Mac let alone a PC. Laptops aren’t cheap. And there are so many other issues…. Saying Windows is still required in 2021 is the nuttiest thing I’ve heard in a long time. Easy to tweet, much harder to think about TCO, and realise where in the journey Malaysia is.
Maybe the best thing was that Malaysian Twitter learned about technology. I doubt many realised the difference between a Pi board vs the 400, but hey, the fact that they talked about tech is still a win (misinformed, but a win).
Today is the first day that in the state of Pahang, we have to encounter what many Malaysians are referring to as the Movement Control Order 2.0 (MCO 2.0). I think everyone finally agrees with the terminology that this is a lockdown now, because I remember back in the day when I was calling it that, I’d definitely offend a handful of journalists.
This is one interesting change for me compared to when I last wrote Life with Rona — Day 56 of being indoors and not even leaving my household, in Kuala Lumpur. I am now not in the state, I am living in a hotel, and I am obviously moving around a little more since we have access to the beach.
KL/Selangor and several other states have already been under the MCO 2.0 since January 13 2021, and while it was supposed to end on January 26, it seems like they’ve extended and harmonised the dates for Peninsular Malaysia to end on February 4 2021. I guess everyone got the “good news” yesterday. The Prime Minister announced some kind of aid last week, but it is still mostly a joke.
Today was the 2nd day I woke up at around 2.30pm because I went to bed at around 8am. First day I had a 23.5 hour uptime, and the today was less brutal, but working from 1-8am with the PST timezone is pretty brutal. Consequently, I barely got too much done, and had one meal, vegetarian, two packs that included rice. I did get to walk by the beach (between Teluk Cempedak and Teluk Cempedak 2), did quite a bit of exercise there and I think even the monkeys are getting hungry… lots of stray cats and monkeys. Starbucks closes at 7pm, and I rocked up at 7.10pm (this was just like yesterday, when I arrived at 9.55pm and was told they wouldn’t grant me a coffee!).
While writing this entry, I did manage to get into a long video call with some friends and I guess it was good catching up with people in various states. It also is what prevented me from publishing this entry!
Day 2
I did wake up reasonable early today because I had pre-ordered room service to arrive at 9am. There is a fixed menu at the hotel for various cuisines (RM48/pax, thankfully gratis for me) and I told them I prefer not having to waste, so just give me what I want which is off menu items anyway. Roti telur double telur (yes, I know it is a roti jantan) with some banjir dhal and sambal and a bit of fruit on the side with two teh tariks. They delivered as requested. I did forget to ask for a jar of honey but that is OK, there is always tomorrow.
I spent most of the day vacillating, and wouldn’t consider it productive by any measure. Just chit chats and napping. It did rain today after a long time, so the day seemed fairly dreary.
When I finally did awaken from my nap, I went for a run on the beach. I did it barefoot. I have no idea if this is how it is supposed to be done, or if you are to run nearer the water or further up above, but I did move around between the two quite often. The beach is still pretty dead, but it is expected since no one is allowed to go unless you’re a hotel guest.
The hotel has closed 3/4 of their villages (blocks) and moved everyone to the village I’m staying in (for long stay guests…). I’m thankful I have a pretty large suite, it is a little over 980sqft, and the ample space, while smaller than my home, is still welcome.
Post beach run, I did a workout with MD via Instagram. It was strength/HIIT based, and I burnt a tonne, because he gave us one of his signature 1.5h classes. It was longer than the 80 minute class he normally charges RM50 for (I still think this is undervaluing his service, but he really does care and does it for the love of seeing his students grow!).
Post-workout I decided to head downtown to find some dinner. Everything at the Teluk Cemepdak block of shops was closed, so they’re not even bothered with doing takeaway. Sg. Lembing steakhouse seemed to have cars parked, Vanggey was empty (Crocodile Rock was open, can’t say if there was a crowd, because the shared parking lot was empty), there was a modest queue at Sate Zul, and further down, Lena was closed, Pickers was open for takeaway but looked pretty closed, Tjantek was open surprisingly, and then I thought I’d give Nusantara a try again, this time for food, but their chef had just gone home at about 8pm. Oops. So I drove to LAN burger, initially ordering just one chicken double special; however they looked like they could use the business so I added on a beef double special. They now accept Boost payments so have joined the e-wallet era. One less place to use cash, which is also why I really like Kuantan. On the drive back, Classic Pilot Cafe was also open and I guess I’ll be heading there too during this lockdown.
Came back to the room to finish both burgers in probably under 15 minutes. While watching the first episode of Bridgerton on Netflix. I’m not sure what really captivates, but I will continue on (I still haven’t finished the first episode). I need to figure out how to use the 2 TVs that I have in this room — HDMI cable? Apple TV? Not normally using a TV, all this is clearly more complex than I care to admit.
I soaked longer than expected, ended up a prune, but I’m sure it will give me good rest!
One thought to leave with:
“Learn to enjoy every minute of your life. Be happy now. Don’t wait for something outside of yourself to make you happy in the future.” — Earl Nightingale
In my experience, the C programming language is still hard to beat, even 50 years after it was first developed (and I feel the same way about UNIX). When it comes to general-purpose utility, low-level systems programming, performance, and portability (even to tiny embedded systems), I would choose C over most modern or fashionable alternatives. In some cases, it is almost the only choice.
Many developers believe that it is difficult to write secure and reliable software in C, due to its free pointers, the lack of enforced memory integrity, and the lack of automatic memory management; however in my opinion it is possible to overcome these risks with discipline and a more secure system of libraries constructed on top of C and libc. Daniel J. Bernstein and Wietse Venema are two developers who have been able to write highly secure, stable, reliable software in C.
My other favourite language is Python. Although Python has numerous desirable features, my favourite is the light-weight syntax: in Python, block structure is indicated by indentation, and braces and semicolons are not required. Apart from the pleasure and relief of reading and writing such light and clear code, which almost appears to be executable pseudo-code, there are many other benefits. In C or JavaScript, if you omit a trailing brace somewhere in the code, or insert an extra brace somewhere, the compiler may tell you that there is a syntax error at the end of the file. These errors can be annoying to track down, and cannot occur in Python. Python not only looks better, the clear syntax helps to avoid errors.
The obvious disadvantage of Python, and other dynamic interpreted languages, is that most programs run extremely slower than C programs. This limits the scope and generality of Python. No AAA or performance-oriented video game engines are programmed in Python. The language is not suitable for low-level systems programming, such as operating system development, device drivers, filesystems, performance-critical networking servers, or real-time systems.
C is a great all-purpose language, but the code is uglier than Python code. Once upon a time, when I was experimenting with the Plan 9 operating system (which is built on C, but lacks Python), I missed Python’s syntax, so I decided to do something about it and write a little preprocessor for C. This converts from a “Pythonesque” indented syntax to regular C with the braces and semicolons. Having forked a little dialect of my own, I continued from there adding other modules and features (which might have been a mistake, but it has been fun and rewarding).
At first I called this translator Brace, because it added in the braces for me. I now call the language CZ. It sounds like “C-easy”. Ease-of-use for developers (DX) is the primary goal. CZ has all of the features of C, and translates cleanly into C, which is then compiled to machine code as normal (using any C compiler; I didn’t write one); and so CZ has the same features and performance as C, but enjoys a more pleasing syntax.
CZ is now self-hosted, in that the translator is written in the language CZ. I confess that originally I wrote most of it in Perl; I’m proficient at Perl, but I consider it to be a fairly ugly language, and overly complicated.
I intend for CZ’s new syntax to be “optional”, ideally a developer will be able to choose to use the normal C syntax when editing CZ, if they prefer it. For this, I need a tool to convert C back to CZ, which I have not fully implemented yet. I am aware that, in addition to traditionalists, some vision-impaired developers prefer to use braces and semicolons, as screen readers might not clearly indicate indentation. A C to CZ translator would of course also be valuable when porting an existing C program to CZ.
CZ has a number of useful features that are not found in standard C, but I did not go so far as C++, which language has been described as “an octopus made by nailing extra legs onto a dog”. I do not consider C to be a dog, at least not in a negative sense; but I think that C++ is not an improvement over plain C. I am creating CZ because I think that it is possible to improve on C, without losing any of its advantages or making it too complex.
One of the most interesting features I added is a simple syntax for fast, light coroutines. I based this on Simon Tatham’s approach to Coroutines in C, which may seem hacky at first glance, but is very efficient and can work very well in practice. I implemented a very fast web server with very clean code using these coroutines. The cost of switching coroutines with this method is little more than the cost of a function call.
CZ has hygienic macros. The regular cpp (C preprocessor) macros are not hygenic and many people consider them hacky and unsafe to use. My CZ macros are safe, and somewhat more powerful than standard C macros. They can be used to neatly add new program control structures. I have plans to further develop the macro system in interesting ways.
I added automatic prototype and header generation, as I do not like having to repeat myself when copying prototypes to separate header files. I added support for the UNIX #! scripting syntax, and for cached executables, which means that CZ can be used like a scripting language without having to use a separate compile or make command, but the programs are only recompiled when something has been changed.
For CZ, I invented a neat approach to portability without conditional compilation directives. Platform-specific library fragments are automatically included from directories having the name of that platform or platform-category. This can work very well in practice, and helps to avoid the nightmare of conditional compilation, feature detection, and Autotools. Using this method, I was able easily to implement portable interfaces to features such as asynchronous IO multiplexing (aka select / poll).
The CZ library includes flexible error handling wrappers, inspired by W. Richard Stevens’ wrappers in his books on Unix Network Programming. If these wrappers are used, there is no need to check return values for error codes, and this makes the code much safer, as an error cannot accidentally be ignored.
CZ has several major faults, which I intend to correct at some point. Some of the syntax is poorly thought out, and I need to revisit it. I developed a fairly rich library to go with the language, including safer data structures, IO, networking, graphics, and sound. There are many nice features, but my CZ library is more prototype than a finished product, there are major omissions, and some features are misconceived or poorly implemented. The misfeatures should be weeded out for the time-being, or moved to an experimental section of the library.
I think that a good software library should come in two parts, the essential low-level APIs with the minimum necessary functionality, and a rich set of high-level convenience functions built on top of the minimal API. I need to clearly separate these two parts in order to avoid polluting the namespaces with all sorts of nonsense!
CZ is lacking a good modern system of symbol namespaces. I can look to Python for a great example. I need to maintain compatibility with C, and avoid ugly symbol encodings. I think I can come up with something that will alleviate the need to type anything like gtk_window_set_default_size, and yet maintain compatibility with the library in question. I want all the power of C, but it should be easy to use, even for children. It should be as easy as BASIC or Processing, a child should be able to write short graphical demos and the like, without stumbling over tricky syntax or obscure compile errors.
Here is an example of a simple CZ program which plots the Mandelbrot set fractal. I think that the program is fairly clear and easy to understand, although there is still some potential to improve and clarify the code.
#!/usr/local/bin/cz --
use b
use ccomplex
Main:
num outside = 16, ox = -0.5, oy = 0, r = 1.5
long i, max_i = 50, rb_i = 30
space()
uint32_t *px = pixel() # CONFIGURE!
num d = 2*r/h, x0 = ox-d*w_2, y0 = oy+d*h_2
for(y, 0, h):
cmplx c = x0 + (y0-d*y)*I
repeat(w):
cmplx w = c
for i=0; i < max_i && cabs(w) < outside; ++i
w = w*w + c
*px++ = i < max_i ? rainbow(i*359 / rb_i % 360) : black
c += d
I wrote a more elaborate variant of this program, which generates images like the one shown below. There are a few tricks used: continuous colouring, rainbow colours, and plotting the logarithm of the iteration count, which makes the plot appear less busy close to the black fractal proper. I sell some T-shirts and other products with these fractal designs online.
An image from the Mandelbrot set, generated by a fairly simple CZ program.
I am interested in graph programming, and have been for three decades since I was a teenager. By graph programming, I mean programming and modelling based on mathematical graphs or diagrams. I avoid the term visual programming, because there is no necessary reason that vision impaired folks could not use a graph programming language; a graph or diagram may be perceived, understood, and manipulated without having to see it.
Mathematics is something that naturally exists, outside time and independent of our universe. We humans discover mathematics, we do not invent or create it. One of my main ideas for graph programming is to represent a mathematical (or software) model in the simplest and most natural way, using relational operators. Elementary mathematics can be reduced to just a few such operators:
+
add, subtract, disjoint union, zero
×
multiply, divide, cartesian product, one
^
power, root, logarithm
◢
sin, cos, sin-1, cos-1, hypot, atan2
δ
differential, integral
a set of minimal relational operators for elementary math
I think that a language and notation based on these few operators (and similar) can be considerably simpler and more expressive than conventional math or programming languages.
CZ is for me a stepping-stone toward this goal of an expressive relational graph language. It is more pleasant for me to develop software tools in CZ than in C or another language.
My CZ project has been stalled for quite some time. I foolishly became discouraged after receiving some negative feedback. I now know that honest negative feedback should be valued as an opportunity to improve, and I intend to continue the project until it lacks glaring faults, and is useful for other people. If this project or this article interests you, please contact me and let me know. It is much more enjoyable to work on a project when other people are actively interested in it!
The uBITX uses an Arduino internally. This article describes how to update its software.
Required hardware
The connector on the back is a Mini-B USB connector, so you'll need a "Mini-B to A" USB cable. This is not the same cable as used with older Android smartphones. The Mini-B connector was used with a lot of cameras a decade ago.
You'll also need a computer. I use a laptop with Fedora Linux installed.
Required software for software development
In Fedora all the required software is installed with sudo dnf install arduino git. Add yourself to the users and lock groups with sudo usermod -a -G users,lock $USER (on Debian-style systems use sudo usermod -a -G dialout,lock $USER). You'll need to log out and log in again for that to have an effect (if you want to see which groups you are already in, then use the id command).
Run arduino as your ordinary non-root user to create the directories used by the Arduino IDE. You can quit the IDE once it starts.
Obtain the uBITX software
$ cd ~/Arduino
$ git clone https://github.com/afarhan/ubitxv6.git ubitx_v6.1_code
Connect the uBITX to your computer
Plug in the USB cable and turn on the radio. Running dmesg will show the Arduino appearing as a "USB serial" device:
usb 1-1: new full-speed USB device number 6 using xhci_hcd
usb 1-1: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64
usb 1-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
usb 1-1: Product: USB Serial
usbcore: registered new interface driver ch341
usbserial: USB Serial support registered for ch341-uart
ch341 1-1:1.0: ch341-uart converter detected
usb 1-1: ch341-uart converter now attached to ttyUSB1
If you want more information about the USB device then use:
$ lsusb -d 1a86:7523
Bus 001 Device 006: ID 1a86:7523 QinHeng Electronics CH340 serial converter
In the last post I had started implementing an Unscented Kalman Filter for position and orientation tracking in OpenHMD. Over the Christmas break, I continued that work.
A Quick Recap
When reading below, keep in mind that the goal of the filtering code I’m writing is to combine 2 sources of information for tracking the headset and controllers.
The first piece of information is acceleration and rotation data from the IMU on each device, and the second is observations of the device position and orientation from 1 or more camera sensors.
The IMU motion data drifts quickly (at least for position tracking) and can’t tell which way the device is facing (yaw, but can detect gravity and get pitch/roll).
The camera observations can tell exactly where each device is, but arrive at a much lower rate (52Hz vs 500/1000Hz) and can take a long time to process (hundreds of milliseconds) to analyse to acquire or re-acquire a lock on the tracked device(s).
The goal is to acquire tracking lock, then use the motion data to predict the motion closely enough that we always hit the ‘fast path’ of vision analysis. The key here is closely enough – the more closely the filter can track and predict the motion of devices between camera frames, the better.
Integration in OpenHMD
When I wrote the last post, I had the filter running as a standalone application, processing motion trace data collected by instrumenting a running OpenHMD app and moving my headset and controllers around. That’s a really good way to work, because it lets me run modifications on the same data set and see what changed.
However, the motion traces were captured using the current fusion/prediction code, which frequently loses tracking lock when the devices move – leading to big gaps in the camera observations and more interpolation for the filter.
By integrating the Kalman filter into OpenHMD, the predictions are improved leading to generally much better results. Here’s one trace of me moving the headset around reasonably vigourously with no tracking loss at all.
Headset motion capture trace
If it worked this well all the time, I’d be ecstatic! The predicted position matched the observed position closely enough for every frame for the computer vision to match poses and track perfectly. Unfortunately, this doesn’t happen every time yet, and definitely not with the controllers – although I think the latter largely comes down to the current computer vision having more troubler matching controller poses. They have fewer LEDs to match against compared to the headset, and the LEDs are generally more side-on to a front-facing camera.
Taking a closer look at a portion of that trace, the drift between camera frames when the position is interpolated using the IMU readings is clear.
Headset motion capture – zoomed in view
This is really good. Most of the time, the drift between frames is within 1-2mm. The computer vision can only match the pose of the devices to within a pixel or two – so the observed jitter can also come from the pose extraction, not the filtering.
The worst tracking is again on the Z axis – distance from the camera in this case. Again, that makes sense – with a single camera matching LED blobs, distance is the most uncertain part of the extracted pose.
Losing Track
The trace above is good – the computer vision spots the headset and then the filtering + computer vision track it at all times. That isn’t always the case – the prediction goes wrong, or the computer vision fails to match (it’s definitely still far from perfect). When that happens, it needs to do a full pose search to reacquire the device, and there’s a big gap until the next pose report is available.
That looks more like this
Headset motion capture trace with tracking errors
This trace has 2 kinds of errors – gaps in the observed position timeline during full pose searches and erroneous position reports where the computer vision matched things incorrectly.
Fixing the errors in position reports will require improving the computer vision algorithm and would fix most of the plot above. Outlier rejection is one approach to investigate on that front.
Latency Compensation
There is inherent delay involved in processing of the camera observations. Every 19.2ms, the headset emits a radio signal that triggers each camera to capture a frame. At the same time, the headset and controller IR LEDS light up brightly to create the light constellation being tracked. After the frame is captured, it is delivered over USB over the next 18ms or so and then submitted for vision analysis. In the fast case where we’re already tracking the device the computer vision is complete in a millisecond or so. In the slow case, it’s much longer.
Overall, that means that there’s at least a 20ms offset between when the devices are observed and when the position information is available for use. In the plot above, this delay is ignored and position reports are fed into the filter when they are available. In the worst case, that means the filter is being told where the headset was hundreds of milliseconds earlier.
To compensate for that delay, I implemented a mechanism in the filter where it keeps extra position and orientation entries in the state that can be used to retroactively apply the position observations.
The way that works is to make a prediction of the position and orientation of the device at the moment the camera frame is captured and copy that prediction into the extra state variable. After that, it continues integrating IMU data as it becomes available while keeping the auxilliary state constant.
When a the camera frame analysis is complete, that delayed measurement is matched against the stored position and orientation prediction in the state and the error used to correct the overall filter. The cool thing is that in the intervening time, the filter covariance matrix has been building up the right correction terms to adjust the current position and orientation.
Here’s a good example of the difference:
Before: Position filtering with no latency compensationAfter: Latency-compensated position reports
Notice how most of the disconnected segments have now slotted back into position in the timeline. The ones that haven’t can either be attributed to incorrect pose extraction in the compute vision, or to not having enough auxilliary state slots for all the concurrent frames.
At any given moment, there can be a camera frame being analysed, one arriving over USB, and one awaiting “long term” analysis. The filter needs to track an auxilliary state variable for each frame that we expect to get pose information from later, so I implemented a slot allocation system and multiple slots.
The downside is that each slot adds 6 variables (3 position and 3 orientation) to the covariance matrix on top of the 18 base variables. Because the covariance matrix is square, the size grows quadratically with new variables. 5 new slots means 30 new variables – leading to a 48 x 48 covariance matrix instead of 18 x 18. That is a 7-fold increase in the size of the matrix (48 x 48 = 2304 vs 18 x 18 = 324) and unfortunately about a 10x slow-down in the filter run-time.
At that point, even after some optimisation and vectorisation on the matrix operations, the filter can only run about 3x real-time, which is too slow. Using fewer slots is quicker, but allows for fewer outstanding frames. With 3 slots, the slow-down is only about 2x.
There are some other possible approaches to this problem:
Running the filtering delayed, only integrating IMU reports once the camera report is available. This has the disadvantage of not reporting the most up-to-date estimate of the user pose, which isn’t great for an interactive VR system.
Keeping around IMU reports and rewinding / replaying the filter for late camera observations. This limits the overall increase in filter CPU usage to double (since we at most replay every observation twice), but potentially with large bursts when hundreds of IMU readings need replaying.
It might be possible to only keep 2 “full” delayed measurement slots with both position and orientation, and to keep some position-only slots for others. The orientation of the headset tends to drift much more slowly than position does, so when there’s a big gap in the tracking it would be more important to be able to correct the position estimate. Orientation is likely to still be close to correct.
Further optimisation in the filter implementation. I was hoping to keep everything dependency-free, so the filter implementation uses my own naive 2D matrix code, which only implements the features needed for the filter. A more sophisticated matrix library might perform better – but it’s hard to say without doing some testing on that front.
Controllers
So far in this post, I’ve only talked about the headset tracking and not mentioned controllers. The controllers are considerably harder to track right now, but most of the blame for that is in the computer vision part. Each controller has fewer LEDs than the headset, fewer are visible at any given moment, and they often aren’t pointing at the camera front-on.
Oculus Camera view of headset and left controller.
This screenshot is a prime example. The controller is the cluster of lights at the top of the image, and the headset is lower left. The computer vision has gotten confused and thinks the controller is the ring of random blue crosses near the headset. It corrected itself a moment later, but those false readings make life very hard for the filtering.
Position tracking of left controller with lots of tracking loss.
Here’s a typical example of the controller tracking right now. There are some very promising portions of good tracking, but they are interspersed with bursts of tracking losses, and wild drifting from the computer vision giving wrong poses – leading to the filter predicting incorrect acceleration and hence cascaded tracking losses. Particularly (again) on the Z axis.
Timing Improvements
One of the problems I was looking at in my last post is variability in the arrival timing of the various USB streams (Headset reports, Controller reports, camera frames). I improved things in OpenHMD on that front, to use timestamps from the devices everywhere (removing USB timing jitter from the inter-sample time).
There are still potential problems in when IMU reports from controllers get updated in the filters vs the camera frames. That can be on the order of 2-4ms jitter. Time will tell how big a problem that will be – after the other bigger tracking problems are resolved.
Sponsorships
All the work that I’m doing implementing this positional tracking is a combination of my free time, hours contributed by my employer Centricular and contributions from people via Github Sponsorships. If you’d like to help me spend more hours on this and fewer on other paying work, I appreciate any contributions immensely!
Next Steps
The next things on my todo list are:
Integrate the delayed-observation processing into OpenHMD (at the moment it is only in my standalone simulator).
Improve the filter code structure – this is my first kalman filter and there are some implementation decisions I’d like to revisit.
Publish the UKF branch for other people to try.
Circle back to the computer vision and look at ways to improve the pose extraction and better reject outlying / erroneous poses, especially for the controllers.
Think more about how to best handle / schedule analysis of frames from multiple cameras. At the moment each camera operates as a separate entity, capturing frames and analysing them in threads without considering what is happening in other cameras. That means any camera that can’t see a particular device starts doing full pose searches – which might be unnecessary if another camera still has a good view of the device. Coordinating those analyses across cameras could yield better CPU consumption, and let the filter retain fewer delayed observation slots.
Another year comes to a close, and this is the 4th year running I’m in Kuala Lumpur — 2017, 2018, 2019, and 2020… Wow. Maybe the biggest difference is that I’ve been in Malaysia for 306 days, thanks to the novel coronavirus. I have never spent this much time in Malaysia, in my entire life… I want to say KL, but I’ve managed to zip my way around to Kuantan (a lot), Penang, and Malacca. I can’t believe I flew back on February 29 2020 from Tokyo, and never got on a plane again! What a grounded globalist I’ve become.
My travel stats are of course, pretty dismal. 39 days out of the country. Apparently I did a total of 13 trips, 92 days of travel (I don’t know if all my local trips are counted frankly), 60,766km, 17 cities, and still 7 countries :) I don’t even want to compare to what it was like in 2019.
I ended that by saying, “I welcome 2020 with arms wide open.”. I’m not so sure how I feel about 2020. There is life beyond travel. COVID and our reaction to it, really worries me.
KL has some pretty good food. Kuantan has some pretty good people. While in KL, I visited a spin studio at least once per day. I did a total of 272 spin classes over 366 days! Not to forget there was 56 days of complete lockdown, and studios didn’t open till about maybe mid-June… Sure I did do some spin in London and Paris too, but the bulk of all this happened while I was here in KL.
I became reasonably friendlier, I became vulnerable, and like every time you do that, you’re chances of happiness and getting hurt probably straddle 50:50. Madonna – The Power of Good-bye can be apt.
This is not to say I didn’t enjoy 2020. Glass half full. I really did. Carpe diem. Simplicity is best. If you can follow KISS principles in engineering, why would you pour your entire thought process out and overwhelm the other party?
Anyway, I still look forward to 2021, with wide open arms, and while I really do think the COVID mess isn’t going away and things are going to be worse for many, I will still be focused on the most positive aspects of 2021. And I’ll work on being my old self again ;-)
I also ended the year with a haircut (number 1/0.5 on the sides) on Monday 28 December 2020. Somewhat of an experiment (does CoQ10 help speed up hair growth?) but also somewhat of a reaction to saying goodbye to December 2020.
udev can be used to block a USB device (or even an entire class of devices, such as USB storage). Add a file /etc/udev/rules.d/99-local-blacklist.rules containing:
While I hope to update this site again soon, here’s a photo I captured over the weekend in my back yard. The red flowering plant is attracting wattlebirds and honey-eaters. This wattlebird stayed still long enough for me to take this shot. After a little bit of editing, I think it has turned out rather well.
Photo taken with: Canon 7D Mark II & Canon 55-250mm lens.
Edited in Lightroom and Photoshop (to remove a sun glare spot off the eye).
Digital TV uses MPEG Transport Stream, which is a container for video designed for lossy transmission, such as radio. To save CPU cycles, Personal Video Records often save the MPEG-TS stream directly to disk. The more usual MPEG is technically MPEG Program Stream, which is designed for lossless transmission, such as storage on a disk.
Since these are a container formats, it should be possible to losslessly and quickly re-code from MPEG-TS to MPEG-PS.
I gave the talk Practicality Beats Purity: The Zen of Python’s Escape Hatch as part of PyConline AU 2020, the very online replacement for PyCon AU this year. In that talk, I included a few interesting links code samples which you may be interested in:
__NOT_A_MATCHER__=object()__MATCHER_SORT_KEY__=0defswitch(cls):inst=cls()methods=[]forattrindir(inst):method=getattr(inst,attr)matcher=getattr(method,"__matcher__",__NOT_A_MATCHER__)ifmatcher==__NOT_A_MATCHER__:continuemethods.append(method)methods.sort(key=lambdai:i.__matcher_sort_key__)formethodinmethods:matches=method.__matcher__()ifmatches:returnmethod()raiseValueError(f"No matcher matches value {test_value}")defcase(matcher):def__decorator__(f):global__MATCHER_SORT_KEY__f.__matcher__=matcherf.__matcher_sort_key__=__MATCHER_SORT_KEY____MATCHER_SORT_KEY__+=1returnfreturn__decorator__if__name__=="__main__":foriinrange(100):@switchclassFizzBuzz:@case(lambda:i%15==0)deffizzbuzz(self):return"fizzbuzz"@case(lambda:i%3==0)deffizz(self):return"fizz"@case(lambda:i%5==0)defbuzz(self):return"buzz"@case(lambda:True)defdefault(self):return"-"print(f"{i}{FizzBuzz}")
fuck grey text on white backgrounds
fuck grey text on black backgrounds
fuck thin, spindly fonts
fuck 10px text
fuck any size of anything in px
fuck font-weight 300
fuck unreadable web pages
fuck themes that implement this unreadable idiocy
fuck sites that don’t work without javascript
fuck reactjs and everything like it
thank fuck for Stylus. and uBlock Origin. and uMatrix.
Way back in 2015 the University of Melbourne had a general-purpose high performance computer system called "Edward", which itself replaced an even smaller system called "Alfred", both named after the Kings of Wessex. Edward was a fairly typical machine for its vintage and, as is normal, when a system is being retired the main researchers were asked what should be different in the new system. What was also normal was their answers; more cores, faster CPUs, etc. Consideration was given to not having an HPC system at all, potentially offloading the demand to a national facility. But cooler heads that possibly understood network throughput and the advantages of fine-tuning a local system to the needs of local researchers prevailed. 
