Path: utzoo!utgpu!watserv1!watmath!att!dptg!ulysses!andante!mit-eddie!wuarchive!cs.utexas.edu!yale!cmcl2!esquire!yost
From: yost@DPW.COM (David A. Yost)
Newsgroups: comp.object
Subject: Re: Stash Collection
Message-ID: <2853@esquire.dpw.com>
Date: 27 Nov 90 17:47:11 GMT
References: <2849@esquire.dpw.com> <1990Nov27.074534.17744@Think.COM>
Reply-To: deutsch@parcplace.com (Peter Deutsch)
Organization: Davis Polk & Wardwell
Lines: 22

Peter Deutsch asked me to post this for him.

The Agoric Systems folks address this problem by adopting an economic model
in which objects pay rent, can be evicted, etc., and can negotiate with
their landlords.  I think their approach is either revolutionary or crazy
(or both), and I find the 'libertarian' political philosophy on which they
base their analysis incompatible with my personal sense of morality, but
they are the only ones I know who are addressing this problem at a
fundamental level.  For more information, you might send mail to
markm@xanadu.com.  They haven't implemented much of this yet.

For a less fundamental but commercially available approach, you might want
to look at Objectworks\Smalltalk, release 4, from ParcPlace Systems.  It
includes some unique facilities for allowing user-written code to intervene
when the storage manager is about to do certain things such as fire off or
continue a garbage collection.  (The Ow\ST garbage collector is incremental
and interruptible.)  I believe this gives you the 'hook' you would need to
de-cache less valuable objects at an appropriate time, i.e., when the
memory manager is under pressure.

 Peter Deutsch
 deutsch@parcplace.com