Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!daemon
From: miller@CS.ROCHESTER.EDU (Brad Miller)
Newsgroups: comp.lang.lisp
Subject: Re: Symbolics co-processor board for the Sparcstation-1 ?
Message-ID: <1989Sep6.000759.15274@cs.rochester.edu>
Date: 6 Sep 89 00:07:59 GMT
Sender: daemon@cs.rochester.edu (Old Scratch)
Organization: University of Rochester Computer Science Department
Lines: 28

I suggest you look more carefully at the engineering of the UXL-400 and the
Sparcstation-1.

1) The UXL needs a 40 bit wide memory; it does not access memory thru the
VMEbus, but from it's own board, or extends it's mem bus to an adjacent
board via ribbon cable. Using host memory would cut performance
significantly. If that's what you want, buy a MacIvory and a Mac-II... it
uses NuBus memory to the severe detriment of processor thruput. (it slows it
down to 3620 speeds; the XL-400 is supposed to be about 5x a 3620 - get
benchmarks from Symbolics). 

2) The Sparcstation-1 has NO bus whatsoever. Where would you plug an
embedded Ivory in? The serial port? :-)

If you want a 13 mips machine, get a 4/330, instead of a 3/160. Why do you
need such speed out of your SUN if you will mostly use the UXL anyway? Sure,
a faster host will give better X and disk response, but it isn't that big a
deal...

The low end of their line is the MacIvory. The high end is the UXL, which is
identical boardwise to their standalone lispm. (XL-400). Comparing apples to
apples, you may, as an edu institution, be able to buy a UXL-400 AND a 4/330
for less than an XL400; I know we can. And the 4/330 can be used for other
stuff; the UXL-400 is accessed via X so needent be accessed thru the host at
all, but, say, a remote Sparcstation.

Why not put UXL-400s into the existing 3/160s and then access them from your
desktop Sparcstation? Leave the 160s in the computer room.