There's a fairly hard cut-off between the design of early OSs with no memory protection (e.g. legacy Mac OS, W95, Amiga, DOS, Locomotive basic), and operating systems which ration memory out to processes (NT, BeOS, Linux, BSD, Solaris). The later group depends on hardware features that the z80 didn't have.
Version 7 unix is in the first camp. Whereas BSD had paged virtual memory well before the IP became open. Also, I think NetBSD requires at least a 32-bit word size.
There was a unix-like in the z80 era called Coherent. On the wikipedia page it says, "There was no support for virtual memory or demand paging." I remember it being advertised in the magazines but never got to play with it, would be interested to hear stories.
Ah I had forgotten. Well you can run the netbsd rump kernel without memory protection, which gives you much of unix (no mmap obviously), but the 32 bitness is probably still an issue, although it might not be you will have to implement 32 and 64 bit types but you could try to do it...
There's a fairly hard cut-off between the design of early OSs with no memory protection (e.g. legacy Mac OS, W95, Amiga, DOS, Locomotive basic), and operating systems which ration memory out to processes (NT, BeOS, Linux, BSD, Solaris). The later group depends on hardware features that the z80 didn't have.
Version 7 unix is in the first camp. Whereas BSD had paged virtual memory well before the IP became open. Also, I think NetBSD requires at least a 32-bit word size.
There was a unix-like in the z80 era called Coherent. On the wikipedia page it says, "There was no support for virtual memory or demand paging." I remember it being advertised in the magazines but never got to play with it, would be interested to hear stories.
[multiple edits, had fun thinking about this]