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From: malcolm@decwrl.DEC.COM@spar.UUCP
Newsgroups: mod.ai
Subject: Re: DEC AI Workstation
Message-ID: <8702190529.AA06912@hobbes.SPAR.CAS.SLB.COM>
Date: Thu, 19-Feb-87 00:29:42 EST
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Posted: Thu Feb 19 00:29:42 1987
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In article <8702121349.AA14488@csv.rpi.edu> yerazuws@CSV.RPI.EDU (Crah) writes:
>	I wouldn't bother with the SUN, especially in a diskless
>configuration.  I wasted  (yes, wasted) nine months trying to develop
>an architecture simulator on Sun 2's.  Little things like a server
>being slow can completely hang your LISP and your editor - so you sit.
>And sit.  And forget what you were doing...

You're right....don't even think about running Lisp on a Sun-2.  On the
other hand Sun-3's (which are three times faster in general than Sun-2's)
make a fast lisp workstation.

BUT, you must have enough memory on the system to make sure that you
don't page when you garbage collect.  I work with both Franz and Lucid
Common Lisp and they both copy the workspace to garbage collect.  When you
have to go to the disk (or network) every time you want to garbage collect
then you lose big.  And then you finish GC and start doing real work again
and all the pages you want have already been flushed.

I suspect that the reason the limited memory isn't as much a factor with
Symbolics workstations is because they do incremental garbage collection.
When you are working normally everything works fast.....but go away for
a while and come back and watch the swap bar turn solid black for a few
seconds.

Franz Common Lisp can run quite nicely in 9M of memory.  Memory is real
cheap these days.  I have 16M on my desk and I almost never page while 
switching back and forth between Lisp and other windows I am using.

As far as performance goes, I have seen a Sun3/160 running anywhere between
.5 and 4 times a Symbolics 3600.  Moving to a Sun3/260 gives you another
factor of two performance improvement.  Sun's can match the speed of a
Symbolics workstation....now if they can just make the environment as nice.

Cheers.

								Malcolm