Please fill me in....

["Arthur D. Flatau" <flatau@CLI.COM>]

   Date: Wed, 3 Jan 90 11:00 PST
   From: Mr. Spock <Spock@SAMSON.CADR.DIALNET.SYMBOLICS.COM>
   Internet-Address:   SPOCK%samson.cadr.dialnet.symbolics.com@riverside.scrc.symbolics.com
   Snail-Mail-Address: American Microsystems Inc. (A wholly owned subsidiary of Gould Inc.)
		       CAD Research Lab.
		       P.O. Box 967
		       Twain Harte, CA  95383
   Phone-Number:       (209)586-7422

       Date: Sat, 23 Dec 89 17:11:23 CST
       From: Arthur D. Flatau <flatau@CLI.COM>

	 [...]

	  No.  In order to run Lisp effectively, you need a decent amount of
	  memory (16Mb, I guess) and a local paging disk.  This would bring the
	  total cost of the workstation up to $15-20K.

							  barmar

       I have a Sun 3/60 with 20Mb of memory.  The main lisp program I run on
       it is the Boyer Moore theorem prover.  It has some (maybe lots) of
       declarations.  It runs faster on my Sun (under Austin Kyoto Common
       Lisp [AKCL]) then on the Symbolics.

   What kind of Symbolics are you comparing to and how much disk/memory?

To a 3645 with 2 190Mb disks (I don't know which ones they are) and
8Mb (2 Mwords) memory.

     I do not have a local paging
       disk.  However if you run AKCL (or Lucid for that matter) with a large
       enough Lisp image you lose big during garbage collection.  This is
       because of the large number of page faults generated.  Lucid seems to
       be a bit better about garbage collecting, but the same problem will
       arise at some point.

   Ahh yes, page faults would be deadly for you which is probably why you
   have(need?) 20mb of memory.  But I experienced the same slowdown in my
   sun setup which had a local paging disk.  So you're saying that there is
   a significant difference between the number of page faults on a Sun vs.
   Symoblics during garbage collection?  Or are there more things involved
   in GC (tag bits?) that create problems for "standard" architectures.?

I normally run the Symbolics with the ephemeral GC on, and the
incremental GC off.  The difference in paging is (I believe) that the
Symbolics ephemeral GC mostly looks at pages that you have used
recently, while the AKCL GC looks through the entire memory.

   [...]

Art