Lilos: A wee async RTOS for Cortex-M (github.com)

The comments in the code are wonderful documentation. I like the applicative mutex, I may borrow the idea! https://github.com/cbiffle/lilos/blob/main/os/src/mutex.rs

Awesome. When I saw it was from Cliff Biffle I got really excited. This is why I visit HN.

Async Rust is great for embedded! Check out https://embassy.dev as well which is very similar but with support for more hardware.

Super cool. A friend of mine built an event based task runner on the PIC18, but this looks even neater.

It looks pretty cool. And is actually something I tried while I was working on futures-intrusive (before I lost most interest in async Rust).

But besides being possible, I'm wondering if its a *realtime* OS in the sense that the term suggests. A realtime OS requires guarantees that tasks run in certain intervals - which seems to require preemption, and thereby "real" stacks. When using a cooperative multi-tasking system it seems any task could prevent all others from running - which voids the realtime guarantees.