19 Apr
2007
19 Apr
'07
10:48 a.m.
Sometimes brevity is the soul of confusion....
At 20:42 -0500 4/18/07, Allison wrote:
Not true as the rainbow also ran CP/M-80/88 as it was a
dual CPU (has a z80).
At 20:42 -0500 4/18/07, Pat wrote:
I'd imagine that Mark meant that the amount of
memory (832k) was
irrelevant to CP/M-80.
At 20:42 -0500 4/18/07, Chris wrote:
Could it access more then 64k under CP/M-80?
Don't
you mean CP/M-86? Not to nit pick...
I don't know about specific Rainbow revisions, but I
was under the impression the 'bow could go up to 896k.
Maybe I'm thinking of the Tandy 2000 via an 3rd party upgrade.
Pat's right, I meant the 8080/Z-80 form of CP/M would (I think) not
access anything above 64k for the Z-80. I remember thinking it would
be a neat hack to make the other 768k into a RAMdisk for CP/M on the
Z-80, using the 8088 to serve it.
Allison's right too, CP/M-80/86 would access the full 832k (or 896k
in a B model) for the 8088 processor to run (and I think that's the
original OS supplied with the machine, though MS-DOS was also
available).
Rainbow PC-100A could not be (I know, and I don't mean that as a
challenge - I'm just talking about factory-supplied options...)
expanded beyond 832k RAM, and the 8087 coprocessor card mine uses was
one of the few ways to expand that far.
PC-100B and PC-100+ (The latter with a hard drive and controller and
a different badge, but otherwise identical to a B) both could be
expanded up to 896k RAM.
In any case, thanks for the clarification(s)!
--
- Mark, 210-379-4635
-----------------------------------------------------------------------
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.