ECUs have very strict timing requirements that would be unsuitable for a general purpose time share system. Linux would be more for guidance and entertainment.

ECUs have very strict timing requirements that would be unsuitable for a general purpose time share system. Linux would be more for guidance and entertainment. You wouldn’t want a malformed mp3 to cause catastrophic engine failure. You would isolate the two systems completely. Likewise something like auto pilot would sit above the ECU and be isolated from anything accepting user data for the same reason - you need hard deadlines for the various navigation functions to operate within - not as tight as the ECU where you are counting click ticks but much more strict then typical general purpose OS.