I somewhat agree with the sentiment, but I think the line is fuzzy. UNIX, as the stories go, originated as essentially an abstraction layer for a single video g

I somewhat agree with the sentiment, but I think the line is fuzzy. UNIX, as the stories go, originated as essentially an abstraction layer for a single video game, all written in assembly, and eventually expanded to have process isolation and a shell. So I'm inclined to think that this could be an OS, as it has to provide subroutines and code to drive hardware and provide an environment for the game to run, an "operating system" if you will. But if you accept that, everything becomes fuzzy. Is the firmware an "operating system" then? The CPU microcode? On systems like the XEROX Alto, the microcode was developed like a sort of OS kernel. I think it's interesting to explore the "lesser meanings" of terms like "operating system" :-)