25 Feb
2010
25 Feb
'10
9:53 p.m.
On 2/25/10, Fred Cisin <cisin at xenosoft.com> wrote:
On Thu, 25 Feb 2010, JP Hindin wrote:
Is that available anywhere now? I ask because I have a Model 1 w/dual
external 3rd party drives and a Model III and I know more about CP/M
than I do about TRSDOS.
I have a friend with an TRS80 Model III would is
looking for some bootable
media w/TRSDOS and, possibly if available, CP/M...
The TRS80 III, like the 1, had ROM in low memory. and therefore couldn't
run any form of "normal" CP/M. FMG, and a few others, produced a
relocated CP/M for model 1 and 3, but it never caught on, AT ALL. When you see mention of a TRS80 Model 1 or 3 CP/M, it
normally means that
the machine has a small but significant hardware mod to permit
switching the memory map around. (That included Omicron, Parasitic
Engineering (Howard Fullmer), Montezuma Micro, etc.)
Is it a "difficult" mod? I.e., would it be worth rolling a modern one?
There were also hardware mods for the Expansion
Interface to run 8"
drives.
I'd guess those aren't too difficult to implement these days. I have
a TM848 in the basement (installed in a Dataram PDP-11-compatible
chassis) that might work nicely on that.
Q: What is the official standard format for 5.25"
disks for CP/M?
Gary Kildall: 8" SSSD.
Heh. I remember that quote when it was fresh.
The Model 4 was very similar to the model 3, but had a
CTRL key on the
keyboard, and directly supported a CP/M compatible memory map.
Interesting to know now. When I was in High School, we had one Model
III and one Model 4 (plus a Wang programmable calc) for the "computer
lab" (later, after I graduated, DEC donated/sold cheaply a room full
of Rainbows). At the time, we were using TRSDOS and I really didn't
see much difference between one computer vs the other.
-ethan