As someone who knows only that QNX is a RTOS and that "real time" is good in some vague hand-wavy way, I found this 2015 comment a very succinct, concrete and illuminating description of one aspect of QNX's architecture that makes it properly real-time.

So thank you very much for the link.

Thank you for adding that link. What I find particularly remarkable is that the author of that comment is John Nagle himself (of Nagle’s Algorithm fame https://en.m.wikipedia.org/wiki/Nagle%27s_algorithm).

> Somebody really should write a microkernel like this in Rust.

I wonder how far Redox's microkernel design is from what that comment describes.