@Animat gets it right - they slipped away from being accessible to developers and being a 'weapon in the toolchest' for tasks where a normal operating system wo

@Animat gets it right - they slipped away from being accessible to developers and being a 'weapon in the toolchest' for tasks where a normal operating system would not cut it, even things like SGI IRIX that was tied into realtime things such as framerates. There was a time when you used QNX as tool of choice when you had a time critical task and a few 'perl scripts' to do the job. The I/O was easy to do and much like how you can put something together with a Raspberry Pi today with minimal domain expertise, back in the day you could with a QNX box. As noted, this is now just not so accessible.