[TUHS] Re: mental architecture models, Anyone ever heard of teaching a case study of Initial Unix?

["John Levine" <johnl@taugh.com>]

It appears that Peter Yardley <peter.martin.yardley@gmail.com> said:
>The DG Nova had a pretty nice architecture. 2 accumulators, 2 index registers, program counter, status register. No stack register tho. There was a micro processor version by Fairchild. 

It did, but it was word addressed which makes it an historical
curiosity like its spiritual predecessors PDP-4/5/7/8/9.

I also have a mental model of a PDP-11 but these days it's more a simplified 386
leaving out the dumb or useless stuff.  I ignore the segments which are useless
other than for 286 emulation, and some of the strange instructions like decimal
adjust and the warty 8 and 16 bit registers.

What's important is the memory model which on a 386 the way it was
invariably set up was a flat 32 bit consistent little-endian byte
addressed memory with a stack and reasonable addressing modes, and 4K
pages for virtual memory.

ARM should be OK too but I have to ask which ARM? There have been so
many generations often not backward compatible.