15 Apr
2021
15 Apr
'21
7:01 a.m.
On Sat, 10 Apr 2021, Dave Horsfall wrote:
On Fri, 9 Apr 2021, Paul Ruizendaal via TUHS wrote:
That worked on the old Radio Shack (Tandy) Color Computer 2 as well.
Until this moment I didn't know it had been demonstrated on any other
architecture.
The Operating System OS-9[1] Level One would detect this and use the
bank-switched memory if it was available. Presumably it kept identical
copies of itself in each bank as the entire address space switched.
Microware OS-9 was *nix-like in look and feel although it was very
different internally I think. OS-9 still exists today.
I started with OS-9 and so found Unix a comfortable environment when I
transitioned over.
[1] Which should not be confused with any operating system running on a
Mac. That's another story.
Rob
Z80 CP/M machines were still competitive in
1981-1983 (Osborne, Kaypro)
And the Aussie Microbee... Wonderful machine, and easily hacked upon.
For example, you could expand the memory by soldering several chips on top of
each other and addressing the CS* line via bank-switching.