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From: Florian Weimer <fw@deneb.enyo.de>
Newsgroups: comp.lang.ada
Subject: Re: Better support for garbage collection
Date: 15 Mar 2001 17:36:55 +0100
Organization: Enyo's not your organization
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Date: 2001-03-15T17:36:55+01:00
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Robert A Duff <bobduff@world.std.com> writes:

> Florian Weimer <fw@deneb.enyo.de> writes:
> 
> > This is solved by double indirection.  Access values are not
> > addresses, but opaque handles.  The compiler is expected to lock the
> > handle to obtain the actual address.
> 
> Ah, so it's sort of like the original implementation of Smalltalk-80 --
> an array of addresses of "instances", and a pointer to an instance
> actually contains the array index?

I don't know about Smalltalk-80, but the same scheme was implemented
on Windows 2.x and 3.x. Of course, with the advent of the 286 and
especially the 386 and virtual memory management, nobody bothered to
unlock the local or global heap anymore.