Welcome to the 3rd issue of TMPDIR Weekly, a newsletter covering Embedded Linux, IoT systems, and technology in general. Subscribe to future issues at https://tinyletter.com/tmpdir and pass it on to anyone else you think might be interested. Please send any tips or feedback to our forum or news@tmpdir.org.

Embedded Linux

Yoe Distro 2021.07 (hebridean) release

• libseccomp is now supported on RISCV32 platforms
• Added native builds for LLVM runtime (libcxx and compiler-rt), which helps in building chromium using pure clang and llvm runtime
• Fix gimp build race, which has been evading for long time especially seen on musl
• Fix install race on python3
• Fix packages to build with glibc 2.34, there are few changes in glibc 2.34 which requires changes in packages e.g. close_range API is available and some compile time defines have become runtime sysconf entries e.g. PTHREAD_STACK_MIN
• SOURCE_MIRROR_URL now supports S3 buckets, this lets you use S3 for creating source mirrors
• Fix freedom-u540 BSP support
• Bitbake is fixed to not spawn into zombie processes on early termination, this was often seen when using Ctrl + C to cancel bitbake during parse stage
• binutils is upgraded to 2.37, systemd is upgraded to 249.1 along with many package version upgrades and newly added recipes

See release for full changelog.

IoT

On the Simple IoT project, still working on the schedule implementation. It is more work than anticipated, but it is turning out well. One technique that has been clarified through this feature implementation is how to keep track of state in a UI widget when a value is partially entered. For example, when a time is entered in local time in the browser, but stored as UTC in the frontend model/backend DB, you can't do the UTC conversion when the time is partially entered. How do you keep track of state while the time is being entered? You could add another state variable to the model. However, a far simpler technique is to simply store the state in the variable you are entering (perhaps prefix it with a special letter or something. We already do this when entering floating point numbers. In this case, we store a magic value in the point Text field when the number is blank. This eliminates automatically turn a blank into a zero and handles the case when you have a '.' entered without any decimal numbers yet. Any time you can avoid adding additional state, this seems to be a good thing. This also illustrates a common theme of the SIOT project -- do more with fewer types.

Other

The career-changing art of reading the docs

Recently read an article and listened to a podcast that explains the benefits of reading documentation. A quote from the article:

If you read a targeted set of docs consistently over a sustained period — say, a couple of years — while actively practicing on that technology, you will be able to perform magic. That’s a promise.

Join our Discourse forum to discuss these or new topics. Listen to previous podcasts at https://tmpdir.org/.

Thanks for reading! Khem and Cliff