Path: utzoo!attcan!uunet!peregrine!elroy!ames!mailrus!cwjcc!hal!nic.MR.NET!shamash!raspail!bga
From: bga@raspail.UUCP (Bruce Albrecht)
Newsgroups: comp.sys.nsc.32k
Subject: Re: More on build your own box (LONG)
Keywords: plan ahead
Message-ID: <1052@raspail.UUCP>
Date: 22 Nov 88 22:49:59 GMT
References: <7648@pasteur.Berkeley.EDU>
Organization: Control Data Corporation, Arden Hills, MN
Lines: 35

In article <7648@pasteur.Berkeley.EDU>, heppell@sim.berkeley.edu (Kevin G. Heppell) writes:
> 3)  The PC bus architecture is just as slow and awkward as the rest of
> the system.  NuBus, at least, is an IEEE standard, supports 32 bits,
> and has a connector which can perform at reasonable speeds.  From what
> I've seen of the inside of a Mac II, the AT-chassis form factor can be met
> with NuBus cards.

I don't have any problems with using NuBus.  Whose version would we use,
since I believe Apple and NeXT have both modified it.

>     Since the 32k series is supposed to be upwardly compatible, it should
> not matter whether or not the on-board 032 or an added 332 or 532 is
> doing the work.  An add-in card will keep initial costs down, allow
> for easy up-grade, and provide for an I/O processor with the high-perf
> one.  For those who _really_ want a 532 based motherboard, consider
> this: you will get a much larger user base through the method I have suggested,
> which makes software and hardware support much cheaper.  And by designing
> in the upgrade, the initial $1000 outlay doesn't disappear when you
> go up a class.  See below for software considerations.

I don't think we should base it on an 016 or 032.  That's like building a
68k system on a 010.  Sure it's cheaper, but it's also going to be slower
and need an upgrade all that much sooner.  Also, if you use the 082 MMU,
you'll probably want to get a '382 for an upgrade to the 332/532, but you
may not need to get a new 382 for an upgrade of the 332 to 532.  Also, the
082 and 382 are programmed differently, so I think it would be better if
we only used one.

I think there may be a number of people who would not be interested in this
design if it uses the 032.  If I had a choice between a home-brew 032, and
a commercial 68030 (i.e., Atari or Commodore) for $3-4k, I'd probably go
for the commercial system, but a $1500-2500 32332 or 32532 system would be
my first choice.

Bruce