An anecdote, possibly true.
Some IBM mainframe guy (Gene Amdahl?) and Seymour Cray were talking shop. Amdahl (or whoever) said to Cray that he'd wished he'd put more smarts into the peripheral side of things on System/360, as Cray did with the CDC 6000 series (and related) machines.
Peripheral Processor Units were so much more flexible. They were actual programmable computers that could run general-purpose code, not just CCW chains. (Or whatever those thinguses were.) In fact, part of the operating system itself -- not just device drivers -- resided in a PPU.
Monday morning I can't remember what I was working before I left for the day on Friday, but I remember stuff like this. (I sure wish a fella could make a living competing in Trivia Nights.)