General public machines (Was: Altair 8800 name Was: Re: Altair 680 Expansion Boards?

Fred Cisin cisin at
Fri Dec 23 13:30:21 CST 2016

> I knew my last missive would provoke at least one or two interesting (if
> not informative) responses. Yours was no exception, and I thank you for it.

not informative responses are inevitable

> For one, I hadn't known that CP/M was written originally to the 8080.. I'd
> always assumed it originated on the Z80. And I don't doubt that RS / TRS-80
> held a large share (until 1982 or so..) of the home computer market.

CP/M was 8080, and was intended for 8080/8085/Z80.  But, as Allison 
pointed out, there was nothing stopping somebody from writing software 
that would run on CP/M that might require a Z80.  Or write the BIOS for 
the computer as Z80.  Therefore, a Z80 machine would be optimal, and if 
you wrote software to be sold into the CP/M world, it had to run on 8080, 
AND, if it made any BIOS calls,  survive a BIOS that could be 8080, 8085, 
or Z80.

> At the time, I was in my (almost) young teens - and at least in the circles
> I traveled, the TRS-80 / Osborne and Kaypro were viewed as boring, stodgy
> machines without any redeeming entertainment qualities - no color graphics,
> no sprites, poor or nearly non-existent audio, expensive joysticks and so
> on.

Boring, certainly.
Not sure if it was sophisticated enough to be stodgy.

> The ability of the machines to serve multiple roles - for both 'serious'
> work and video gaming / music - was a huge selling point in the early days.
> This is one of the reasons that the C64 was so massively successful - it
> pretty much had something for everyone, as the saying goes. That, and the
> price of the base machine was just amazingly low for the time. Ditto for
> the VIC-20.

Ah! Therein lies the rub.
The TRS-80 wasn't any good for some things.  As a primarily entertainment 
machine, it was rubbish.  No color, no sound, no joysticks, grossly 
inadequate graphics.   (some of which could be worked around)
If you were looking for an games/entertainment machine, it would be 
outside of the consideration set.  Of the set of people looking for a 
games/entertainment machine, "NOBODY has one."
Best game on it was "Adventure". 
Best graphics was Lim's "Android Nim"

On the other side of the market, the TRS-80 did not have 80x24 text, and 
had a memory map that was incompatible with CP/M.   Parasitic Engineering 
(Howard Fullmer!) and Omikron, both made [somewhat expensive] sandwich 
boards for the TRS-80 to change that memory map, and to add 8" SSSD drive 

Of the original "Big three" (Radio Shack, Apple, Commodore), who came 
first, Apple was the only one with entertainment capabilities, but they 
priced it out of your market.

Later, the Commodore Vic-20 and C64 were aimed at your segment of the 
market, and priced appropriately.
Radio Shack's later "Color Computer" (6809!) was far more appropriate, but 
it also suffered some crippling design decision errors.

> the very early 1980s, when I was about 15, my father decided to buy a
> home computer. (Before that, he had a TI Silent 700 that dialed up to a
> Univac mainframe.) I remember him doing hours of research comparing the
> Apple II, the TRS-80, the Commodore PET, and probably some of the S-100
> machines. He eventually chose the Heathkit H89. I^@^Yll have to ask him
> exactly why, but I know that he^@^Ys always liked good-quality tools, 
> and the combination of the Heathkit design, the Z80 CPU, and CP/M seemed
> like the best combination of tools at the time.

Apple II, TRS-80, and Commodore PET didn't have 80x24 screen text!
THAT was why my cousin rejected them and went with a Heathkit.
If you want to be able to use it as a terminal, . . .

Later, add-on cards for Apple2 came out for 80 column.
TRS-80 didn't get 80x24 text until the Model 4 (which is what the Model 3 
should have been)   (Model 2/12/16 was never intended to be a "Home" 
computer, and was marketed for small business)

Grumpy Ol' Fred     		cisin at

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