Hello!

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 others. -- -tony ard12(a)eng.cam.ac.uk The gates in my computer are AND,OR and NOT, not Bill