I've got more familiar later with PS2, as I move to another studio, and was an audio programmer there (Treyarch) and had to do a lot of "PS1" programming on the SPU. I was later reading an article on the TRON operating systems, and found that a lot of the primitives on the PS2 were based on it, even the scheduler to the point - https://en.wikipedia.org/wiki/TRON_project - but never got much of it.

Oh, these were some exciting times! - the whole systems was there open for you to see (at least from the software level, and to some point HW).