TRS80, other than model 1

Fred Cisin cisin at
Sat Jun 13 11:06:27 CDT 2015

>> something totally off topic  from the 8S  machines   there are   some
>> trs80 radio shack things that are huge like the MODEL 2 was but these were
>> later and  had a 3  number designator ?  there are many as I remember  one
>> will be  kept  another kept  for offsite displays  but  the  others  will
>> goooooooo........
> I don't remember anything beyond the II/12/16 series, but no one tells
> me anything.

In addition to the model 1, . . .
The model 1 line was converted from a "component" system to a single box.
For those not familiar, it resembled a Northstar Dimension.  Keyboard, 
screen, two 5.25" floppies in a terminal like case.  That was the model 3.
Default disk format was double density.  Since the WD 179x controller 
could not write a truly exact model 1 format single density disk (did not 
support certain data address marks), there were some kludges and changes 
in TRS-DOS, so there were minor glitches in the "upgrade path".
Radio Shack eventually cut a deal to market L-DOS as TRS-DOS 6.
("And Randy Cook is now finally collecting royalties!")

Soon, the model 4 was made available - same basic machine with 80x24 video 
(V 51x16), green screen, a few missing keys provided, and ability to 
remap the ROM from the memory map.  Finally, CP/M was available without 
memory remapping hardware, nor software kludge of having TPA not in low RAM.
The college got a whole lab full of model 3's converted into model 4's, at 
a price per each that was only slightly more than buying new model 4's.

Model 4P was luggable version, vaguely resembling early Compaq.

Model 2 wasn't what I would call "huge", but such is relative.
It was completely unrelated to model 1, other than name, and
naming it's OS (mutually incompatible with model 1/3) "TRS-DOS".
But, CP/M was also available.
It had an 8" drive, and "huge" external case if you wanted more
than one.

Radio Shack came out with a 68000 CPU board!    and Xenix
It could be used instead of the Z80 CPU, or have BOTH!  (12 and 16)

In terms of "huge", there were a few other machines that rarely,
if ever, actually made it to market, such as the "Tandy 10",
built into a desk, and sold exclusively through
"Radio Shack Computer Center"s.

Grumpy Ol' Fred     		cisin at

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