Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!peregrine!ccicpg!legs!greg
From: greg@legs.legs (Greg Ebert, a.k.a GJ EBERP)
Newsgroups: comp.sys.nsc.32k
Subject: Re: various questions
Summary: Tips from a do-it-yourself'r
Message-ID: <204@legs.legs>
Date: 16 Nov 89 18:34:22 GMT
References: <1252@unify.UUCP>
Organization: AST Research, ASIC (VLSI) Development, Irvine, CA
Lines: 29

Building an entire system from scratch is not something for
the light-hearted. After you figure out what kind of enclosure,
bus, features, etc you want, you can start the real nitty gritty
stuff. Chances are that you will not save any money doing it
yourself versus buying a complete system. I won't even comment
on the amount of time you need to invest. A few months ago,
someone was selling a 16 Mhz 32016 with 8Meg RAM, 80Meg disk, and
running Sys V for $1200.

If you're gonna build a system from scratch, I *STRONGLY* urge
you to carefully wire-wrap it. The basic CPU/MMU/FPU/TCU and
associated buffers contains hundreds of connections, making it
almost impossible to solder point-to-point. If you have the time
and $$$$$$$, whip-up a PC board ( a major task, believe me ! ).

I have had great success wire-wrapping boards with the Vector
Slit-N-Wrap stuff which allows you to go point-to-point without
stripping or cutting wire.

I'm building my 32032 from a 6Mhz chipset I bought from Jameco
Electronics (mailorder) for about $75 a few years ago (see how long
it takes to build it yourself ?). I'm using S-100 cards, and a
modified bus pinout to handle 32 Data/ 24 Address bits while still
supporting 8-bit S-100 cards. If I had to start over, I would use
the 32016 and build it around the PC-AT bus as a bus-master device
(see your local IBM Technical Manual). That way, I can use all of
the cheap RAM/video/serial/disk/MODEM cards out there.  

Good luck on your endeavor !