From: A.R. Duell <ard12_at_eng.cam.ac.uk>
Date: Sun Mar 16 16:14:16 1997

Greetings fellow old-computer enthusiasts.

A few words about my interests. I'm mostly interested in 1970's
minicomputers and early workstations - the sort of machine where the CPU
is built up from a few 10's (or a few hundred) TTL chips. It's great fun
to hook a logic analyser to the output of the ALU and watch the data being
processed. That's something you can't (easily) do with a microcomputer.
And there's a certain joy to single-stepping the microcode on a PDP11/45
and figuring out just how it executes some instructions.

I'd love a machine built from discrete transistors, but nobody's offered
me one yet. I have a couple of programmable calculators with no chips in
them, but no complete computers.

I try to keep clear of the early 1980's micors that used some kind of
custom gate array (often in the video side). It's impossible to get
spares, so fixing them is something of a problem. I do have a number of
micros of that period using standard TTL chips, though. I do have some of
the machines with custom gate arrays (Oric, Atari 400, etc), but I don't
depend on them

Since somebody else mentioned the PC-jr, does anyone have a list of all
the PC-family models that existed? So far I've obtained the original PC,
PC/XT, PC/AT (both versions of the motherboard), XT model 286, PC-jr,
Portable PC (the 'sewing machine' case), and parts of a PC 3270. I know
I'm missing the convertable (? - laptop, I think), PC/370, AT/370, and I'm
not including the PS/2 range (yet!).

I try to keep my machines in working order - restoring them is most of the
fun, actually. And I use them for real work - in fact I don't think I own
a computer that would fit in on this list :-)

Am I unusual in that I also collect schematics and Technical manuals? I
find them as valuable as the machines, and buy all I can find. I own them
for machines I don't yet own, and possibly never will own. But they're
interesting to read none-the-less. Incidentally, I am looking for a
(copy?) of the XT model 286 motherboard schematic - that's the only one of
the original TechRefs that IBM can no longer supply, and I have all the

The gates in my computer are AND,OR and NOT, not Bill
Received on Sun Mar 16 1997 - 16:14:16 GMT

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