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From: Brian Rogoff <bpr@shellx.best.com>
Subject: Re: newbie Q: storage management
Date: 1997/05/09
Message-ID: <Pine.SGI.3.95.970509120443.10301B-100000@shellx.best.com>#1/1
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References: <5k5hif$7r5@bcrkh13.bnr.ca> <dewar.862915787@merv>
 <E9rMAn.93B@world.std.com> <JSA.97May7204713@alexandria>
 <E9w2oL.Hu7@world.std.com>
Newsgroups: comp.lang.ada
Date: 1997-05-09T00:00:00+00:00
List-Id: <comp.lang.ada>


On Fri, 9 May 1997, Robert A Duff wrote:
> In article <JSA.97May7204713@alexandria>, Jon S Anthony <jsa@alexandria> wrote:
> >> purpose of a GC annex would be to standardize whatever hooks there are
> >> (such as procedures for turning it off and on, specifying how many
> >> generations you want, and so forth).  But even within the GC community,
> >> there are strong disagreements about what such hooks ought to look like
> >> -- some people don't like generational GC, so what's that hook supposed
> >> to mean?
> >
> >True enough.  One obvious way out of this for Ada is the generalized
> >version of what Robert called out as a "compromise": a subsystem of
> >generics which offered several variants.  A single global GC handling
> >all dynamic memory issues isn't really needed.  In fact, this is an
> >area where Ada could do something a little different by offering the
> >ability to have multiple collectors per application targetting the
> >specific needs of specific types (or classes of types).  This is the
> >sort of thing that I've been working on.
> 
> I'm very much looking forward to seeing what you've done (will it be
> public?) but I must say I'm skeptical.  All the GC folks say, "GC is a
> global problem", and I tend to agree.  I mean, if so-and-so- pool is
> GC'ed, you still have to find all the pointers into it.
> 
> - Bob

I've seen some similar ideas from the C++ community for a number of years,
so I think Jon's suggestions have merit. There are a number of collectors, 
of various levels of transparency, which can be accessed from 

	http://stork.ukc.ac.uk/computer_science/Html/Jones/gc.html

one of them, Cmm (ftp://ftp.di.unipi.it/pub/project/posso/cmm/) seems to 
be similar to what Jon is describing for Ada. There are also proposals on
how to make C++ "GC friendly" without changing it too much; since Ada is 
similar some of the same considerations apply. 

-- Brian