The late, great TRS-80

Ethan Dicks ethan.dicks at gmail.com
Wed Jun 27 12:02:03 CDT 2007


On 6/27/07, Roger Merchberger <zmerch-cctalk at 30below.com> wrote:
> >I'd say that if it can't play games (graphical or at least a multi-line
> >text display), then it's not what I'd call a *home* computer.
>
> Why do you need a multiline display to play games?

Need?!?  If it doesn't provide food, shelter, or security, I'd say
"need" isn't the right idea...

> In college, I had to write a game for the Heathkit 3400 microprocessor
> trainer (one line of 6 7-segment LEDs) and it was quite enjoyable. I can't
> see why having more than 5x the display size and real alpha capabilities
> means it can't play games...

Can't play games?  Of course a 3400 or a KIM or an AIM-65 can play
games.  They however are incredibly limited compared to even a
VIC-20's 22x23 screen or a more common 40x25 screen or a luxurious
80x24 screen, or, as I mentioned earlier, even a printing terminal.  I
played plenty of games on a DECwriter with an acoustic coupler.  The
"active region" was only one line, but I could see everything that
went before.  When your active region is your only region, the burden
is on the player to remember what just happened, and on the game
designer to create games that fit into 6x1 or 20x1 or 32x1 characters,
especially when it's done with 7-segment displays.

Think back to the games in Dave Ahl's "101 Computer Games" - many of
those could be played on a small alphanumeric single-line display, but
it makes the game harder for the player to remember the details.  Try
the FOCAL classic "Hammurabi" on a 6x1 display.  At least something
like a lunar lander works OK on a tiny display.

Not that it was a standard size in 1977, but as soon as you get into
character grids like 4x20 or 2x40 like some of the inexpensive modern
LCD displays, that second dimension adds layers and layers of ease to
game design and game play.

> The only reason I feel Tony's HP can't be classified as a microcomputer is
> because I was taught that a microcomputer utilized a microprocessor, and I
> was taught that the definition of a microprocessor is a processing solution
> contained entirely on one chip. Anything larger (more than one chip) and
> it's a mini. As that definition has always seemed logical to me, I've
> always stuck with it.

While I mostly agree with your definition, there are plenty of
exceptions that prove that you have to be flexible.  The RCA 1801 is a
pair of chips that's functionally compatible with the 1802 (and only
slightly older).  Does that mean that the 1801 is a mini, and the 1802
is a micro?  The PDP-8 is normally considered a mini, but from the
VT78 onward, it's been implemented commercially with an IM6100 or
IM6120 microprocessor - while one might argue that only the VT78 and
DECmates are micros, they can use many of the same peripherals, have
the same amount of memory, and run more-or-less the same OS (minor TTY
interface instruction flag variations aside) so provide a similar user
experience to, say, a PDP-8/e with a VT100 attached to it.  Does that
make the DECmate I a mini or the PDP-8/a  a micro?  I'd say that it's
a rather blurry line there.  One can escape sematically ("the IM6100
is a microprocessor implementation of a minicomputer architecture"),
but then what's an Intercept Jr?  _That_ is assuredly a single-board
micro by just about any definition you can propose (1K-4K of RAM,
LEDs, toggle switches, IM6100 processor chip, single board...) except
the PDP-8 instruction set.  The DECmate I can take up to four 14"
drives that each dwarf the CPU in volume and weight, along with two
dual 8" floppy drives - in other words, a full 6' rack of drives... is
it still a micro?  I don't recall a 1970s "home computer" with a set
of peripherals as large as a phone booth, and that's just by adding a
single card into the DECmate (the RL278).  When you get bored, you can
even borrow a couple of those drives and hang them off of your
contemporary VAX-11/780 (or your 1985-era microprocessor-based
MicroVAX II).

Quite a few fuzzy boundaries in there if you look a few years forward
into the 1980s.

> If one uses my definition for microcomputer, it might be possible to
> actually figure out what the first home microcomputer is - find the very
> first one in existence, and it could've been used at home. ;-) If one takes
> the "Micro" part out of the equation, I see no reason why Tony's HP can't
> be considered a home computer, tho.

I'm still leery of grouping Tony's HP in with "home computers".  Since
it has a single point of access - the keyboard and display, it's easy
to argue that it's a "personal computer", but then, so would be a
PDP-8/a that one bought to use at home (yes... that was done back in
the day, just not as commonly as with cheaper machines).

One of the problems of "firsts" is that there is no single definition
as to all the elements that make something "the" first.  It's a lot
easier to say "one of the first" with less fear of contradiction.  The
classic case we've been arguing has been PET/Apple/TRS-80... I think
as the events recede into the distance, it will most likely be
considered that all three came out "about the same time" and all three
were popular examples of wildly successful "home computers".  Each one
of them can lay claim to the first this or the first that, but the
trio have more of a significance to me that they were the next wave
after the flurry of S-100 machines that were also an incredible
success just a few years earlier.  Since I got into computing as a
kid, about the time all this was happening, I can say that from my
viewpoint, I knew there were computers in some people's homes, mostly
Hams, they were big, boxy, expensive, and "hard to use" (remember -
this is a 10-year-old kid's view).  When the PET and the the Apple and
the TRS-80 came out, they were physically smaller than an Imsai and a
ADM3A, "easier to use" since they *all* had BASIC in ROM, and did not
require addons to be purchased out-of-the-box (the original PET had a
cassette player built-in, the early TRS-80s were either sold with
cassette players, or you could use one you probably already owned).
At the very least, you could turn them on and be entering a BASIC
program in seconds, even if you couldn't save it.  Not so with an
Altair or a KIM or an Elf.

-ethan



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