OTP 25

May 26, 2022 • Issue 35

Editor's note: I'm going on parental leave (newborn incoming) and you might get a big ol' gap in the newsletter. It will depend on whether the new family situation ends up CPU or IO bound essentially. If I have some spare cycles I'd love to keep making newsletter issues during June and July but if not I won't be sweating it. For Nerves updates I suggest following the Nerves twitter and the #nerves channel on the Elixir slack. But more importantly, have a great summer! Until next time, here's the news.

Official project updates

If you did not attend Code BEAM in Stockholm you may have missed Kenneth Lundin's traditional run-down of the latest release. Fear not, the information is also available on the Internet. What relevance does this have to our dear Nerves? Well, the ARM64 JIT is here now. This should give a good performance boost to the Pi4 and any other ARM64 devices you use. There are also improvements to the crypto module and the CA store usage. There's more in there, most of it struck me as Erlang-level and if it has impact on Elixir I'd expect to see it in 1.14 at earliest.

The JIT is the big reason that we get a whole new nice batch of systems to enable OTP 25. We also get Buildroot 2022.02 and 2022.02.1.

As a note on the potential for an ARM 32 JIT there has been discussion about building and maintaining that. There's interest from a few different parties and from what I gather the conversation between the EEF, the Erlang/OTP team and the interested folks seems hopeful. That'd be a nice boost to the older Pi devices and much more. Not as snazzy as making things go fast on Apple Silicon of course :)

Overall system release notes

This release updates to Buildroot 2022.02.1 and OTP 25.0. While this should be an easy update for most projects, many programs have been updated. Please review the changes in the updated dependencies for details.

Updated dependencies

On any RPi 4 system the new JIT will start by default.

The base buildroot system has the most in-depth notes:

nerves_system_br, v1.19.0

This is a major update that pulls in Buildroot 2022.02.1 and Erlang/OTP 25.

No longer install ERTS to the release. This means that the Mix release generator needs to install ERTS, but it had been doing this and it had been ignored. No changes to your project are needed. ERTS will be under /srv now on the device rather than /usr.
It’s now possible to use the start.boot boot script. It’s no longer scrubbed from the release.
Build a host version of Erlang so that the host and target Erlang definitely match. This had been removed to speed up builds in the past. However, it did not work when compiling the new JIT. This is the “safe” option since mismatched host and target Erlang versions could cause problems.

Systems updated:

Other updates

nerves_livebook, v0.6.1

Updates
- Include :kino_vega_lite so that graphs render again. (Thanks @petermm)
- Improve WiFi configuration book (Thanks @petermm)

Community updates

Code BEAM notes

We pulled together a fun little crew for the Code BEAM pre-hack. I fully intend to write up a few notes on my experience with the conference but they are not ready. For our event specifically Frank brought Pi Zero devices with OLED Bonnets so we had plenty to play with :) Setup was chaotic, which I'll take responsibility for. I think a good time was had by all.

See pictures for evidence of fun.

Supporting the Nerves project

We want to encourage everyone to contribute in whatever way works for them. Here are some ways we currently recommend:

Write or port a new hardware library and include it in the Elixir Circuits collection.
Give money to the project via Open Collective.
Get in touch about taking over maintenance duties for some libraries, we might be able to provide you hardware.
Apply for an EEF stipend on something Nerves-related and build it. We can help if you have questions about this.
Send corrections or improvements for documentation wherever it fails to help you.
Write about Nerves, give talks about Nerves. Make videos about Nerves. It is all good.

Finally, if you have questions about the newsletter or want to suggest something you can simply respond to this email it will go directly to me, Lars, who edits this thing. Let me know what you think.

- Lars, Underjord.io