[Coco] TRS-80 and Maximum PC Magazine

[gene heskett]

On 9/13/22 10:52, Steve Ostrom via Coco wrote:
> In the most recent Maximum PC Magazine, October 2022, on page 70 they have an article entitled, “Machine of the Month : Tandy TRS-80 (1977)”  It’s a pretty good read.  It goes into the history of the TRS-80, including development and software, and then a help to the reader on how to emulate this Z80 computer, which seems to be a bit problematic.
>
> Hope you enjoy the read.
I hope those of you who did have hands on experience had better luck 
than I did with
the Z-80. I bought 2 microprofessor boards to make an ATS for an early 
Sparta FM
transmitter that looked like a remote control with automatic logging if 
the FCC came
calling.

But one on them came with an iffy Z-80, iffy as in the E8 hex code that 
was supposed
to switch its foreground and background register sets, only worked 
around 90% of the
time. With only sunlight to erase my 2708 uv eproms it took me a couple 
months to
confirm I had a duff Z-80. And Zilog refused to warranty it.

That cemented my resolve to never again consider using a Zilog product 
in anything.

The RCA 1802 I used in my first project just sat there and ran for about 
17 years.

So did the coco one I used for an edisk for a gvg300-3A/B, 8x faster 
that gvg's own offering
for $20,000, 16 years and two disk controllers blown by lightening 
hitting the STL tower in
the back yard.

Running os9 v1.00 level 1, and I'd put "the forgotten chip" in it. That 
was so handy with
its ability to reach into a $250,000 switcher and do signature analysis 
when one of gvg's
custom made chips went south. I was able to make work-a-rounds for 
module failures
grass wanted $1700 for, had one on the shelf and no warranty it was 
good. In that
case I fixed it with a TI op-amp that sold at $1.38 at the time. And it 
was enough faster
you could see the color phase shift on the bus to bus fade. I should 
have ordered a whole
stick and swapped them all. Available time saw to it that it didn't get 
done.

Old memories...
> --- Steve ---
>
>
> Sent from Mail for Windows
>


Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>