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From: lamaster@pioneer.arpa (Hugh LaMaster)
Newsgroups: comp.arch
Subject: Re: What should be in hardware but isn't (LISP hardware?)
Message-ID: <2932@ames.arpa>
Date: Wed, 30-Sep-87 13:11:38 EDT
Article-I.D.: ames.2932
Posted: Wed Sep 30 13:11:38 1987
Date-Received: Sun, 4-Oct-87 21:34:53 EDT
References: <581@l.cc.purdue.edu> <28200048@ccvaxa> <2910@ames.arpa> <2917@ames.arpa> <15393@amdahl.amdahl.com>
Sender: usenet@ames.arpa
Reply-To: lamaster@ames.UUCP (Hugh LaMaster)
Organization: NASA Ames Research Center, Moffett Field, Calif.
Lines: 41
Keywords: LISP and Prolog machines

In article <15393@amdahl.amdahl.com> chuck@amdahl.amdahl.com (Charles Simmons) writes:

>In article <2917@ames.arpa> eugene@pioneer.UUCP (Eugene Miya N.) writes:

>>It's pretty obvious to putting vector and floating point hardware
>>in Silicon with products like the Weitek, but I was having a discussion
>>with a colleague about LISP machines, Intellicorp and all those
>>companies doing "AI."  What about putting CDR hardware into machines?
>>this arena.  Agree or disagree?  Aren't Symbolics, TI, LMI doing okay?

>John Hennesy was giving a talk on RISC architechtures in Santa Clara
:
>MIPS processor running LISP and dedicated LISP architechtures running
>LISP.  MIPS seems to win big.
:

On a lot of benchmarks, a general purpose (e.g. MIPS, 68020, etc.) processor
will run faster than a special purpose LISP machine.  However, the speed of,
and behavior during the process of, garbage collection, is not always so well
advertised.  CDR support is easily added to any general purpose machine, even
a "RISC" machine, but probably not necessary.  But, it is a good idea
(actually, I would like to see more machines with a "descriptor" hardware data
type that could be used for lists, pointers, and vectors).  Hardware garbage
collection support is an entirely different question.  However, the
performance advantage of the LISP machines has been eroded for the simple
reason that general purpose machines, being used in a much bigger marketplace,
have typically gone through new generations much more quickly and tend to use
current technology.  It is difficult to finance the level of R&D necessary to
do that for a special purpose processor.  AI machines are not unique in this
respect.





  Hugh LaMaster, m/s 233-9,  UUCP {topaz,lll-crg,ucbvax}!
  NASA Ames Research Center                ames!pioneer!lamaster
  Moffett Field, CA 94035    ARPA lamaster@ames-pioneer.arpa
  Phone:  (415)694-6117      ARPA lamaster@pioneer.arc.nasa.gov

(Disclaimer: "All opinions solely the author's responsibility")