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From: obrien@aero2.UUCP
Newsgroups: comp.lang.smalltalk
Subject: Re: Severe Limitation of Smalltalk for Big Projects
Message-ID: <404@aero2.ARPA>
Date: Mon, 29-Jun-87 15:33:56 EDT
Article-I.D.: aero2.404
Posted: Mon Jun 29 15:33:56 1987
Date-Received: Fri, 3-Jul-87 06:04:57 EDT
References: <3005@oberon.USC.EDU> <1384@tekchips.TEK.COM> <3065@oberon.USC.EDU>
Reply-To: obrien@aero2.UUCP (Michael O'Brien)
Organization: The Aerospace Corporation, El Segundo, CA
Lines: 43

In article <3065@oberon.USC.EDU> barad@othello.usc.edu.UUCP (Herb Barad) writes:
>In article <1384@tekchips.TEK.COM> allenw@tekchips.TEK.COM (Brock) writes:
>>With Smalltalk, like all languages, care must be taken to distingish
>>between between the characteristic of a particular implementation
>>and the fundamental limitations of the language.  Some commercially
>>available Smalltalk implementations have much more severe limitations
>>than those attributed to PS (its HARD to support a 16meg object
>>space on a PC) while others do not have this particular limitation.
>
>Sorry, you are absolutely right.  I did not mean to imply the
>limitation was in the language itself (it certainly isn't), I meant
>the particular implementation.  Also, this type of restriction does
>apply to many implementations, but I hope not to all.

Speaking to the specific problem, I've gotten a few things straightened
out with ParcPlace Systems which may help.  If you have a license to use
PS on your Sun, then (according to them) you are licensed to use any VM
and any VI on that machine, as far as they're concerned.  In particular
you can run BS II on that machine, and with its generation scavenging
and lack of an OT, its memory system is sufficiently different not to
suffer from this lack of space problem that PS has, apparently, inherited
from the Sun-2.  Unfortunately it is a) a research vehicle and hence
buggy, and b) runs something like 5-6 times slower than PS.

I recall reading somewhere that at least one of Tektronix' implementations
also uses generation scavenging and hence does not suffer from space
limitations (these two are only somewhat related, by the way).  A
Tektronix salesman once sounded me out as to whether I thought they should
consider porting their implementation to Suns and selling it there (this
was before ParcPlace Systems came into existence) and I told him
emphatically that he should.  Tektronix has done some admirable work on
the image since starting up their product.  Among these I certainly
include their notion of attaching a Dictionary to every Workspace which
holds permanent copies of variables defined as temporaries in DoIts which
are typed and evaluated in the Workspace.  Makes post facto debugging
possible, which basically can't be done now unless you define globals in
Smalltalk (the SystemDictionary).  They have lots of nice little wins like
that spread around in their system.
-- 
--------
Mike O'Brien
obrien@aerospace.aero.org
{sdcrdcf,trwrb}aero!obrien