I think we're at something like 235 millions cars on the road today with QNX inside. The volume blows my mind. We're also hiding inside lots of healthcare products, industrial control systems, etc.
There's lots of interesting key differences between something based on Linux, for example, and QNX. Worth digging into if you're interested in these things. My colleague wrote a short ebook and the intro has a good summary: https://gitlab.com/elahav/qnx-rpi-book/-/tree/master/pdf
> My colleague wrote a short ebook and the intro has a good summary
Can you recommend books or papers on how the kernel works, and what makes it better than e.g. L4/sel4 or Mach?
There is however also TRON:
https://ethw.org/Milestones:TRON_Real-time_Operating_System_...
which was demoed running on an 80186 with _multiple_ windows running videos w/o dropping a frame.
Described as "The most installed operating system in the world":
https://www.linuxinsider.com/story/the-most-popular-operatin...
Unfortunately, the U.S. State Department viewed the Japanese plan to place it on all computers in their educational system as anti-competitive.
Really wish it was available for the Raspberry Pi.