TRS-80 bootable media request

[Tony Duell]

> 
> On 2/25/10, Fred Cisin <cisin at xenosoft.com> wrote:
> > On Thu, 25 Feb 2010, JP Hindin wrote:
> >> 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.
> 
> 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.

My suggestion (as somebody who grew up with the M1 and later the M3 and 
M4) is that uou get a copy of LDOS and learn to use that. It's a much 
nicer OS than CP/M. If you want to run CP/M there are, IMHO, nicer 
machines to run it on (the Epson QX10 comes high up my list..), but LDOS 
only runs on the TRS-80 and clones.

> 
> > 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?

It's non trivial. It was, IIRC, a PCB that fitted between the Z80 and its 
socket, and which modified the address coming form the Z80 so that RAM 
could appear at the bottom of the memory map (as CP/M requires). Of 
course with an output port to swithc between CP/M and TRS-80 modes.

> 
> > 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.

Does anyone have any (real) information on the 8" drive modes for the M3 
and M4? I would like to try an 8" drive on one of those machines.

-tony