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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: Garbage Collection in Ada
Date: 1996/10/20
Message-ID: <DzL6xB.Lwz@world.std.com>#1/1
X-Deja-AN: 190791397
references: <01bbb910$f1e73f60$829d6482@joy.ericsson.se>
 <Pine.GSO.3.93.961017160658.10939A-100000@sky.net> <dewar.845608007@merv>
 <199610181934142408603@dialup101-3-15.swipnet.se>
organization: The World Public Access UNIX, Brookline, MA
newsgroups: comp.lang.ada
Date: 1996-10-20T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <199610181934142408603@dialup101-3-15.swipnet.se>,
Lars Farm <lars.farm@ite.mh.se> wrote:
>- How large is the probability that this occurs?

(Where "this" = "conservative GC fails to collect some garbage".)

I don't see any way of assigning a numeric probability to it.  That's
the main thing that makes *me* nervous about it.  I mean, there's
nothing under the programmer's control that can let you know if or when
this sort of bug might happen.

You do have a point, though.  For example, many compilers use hash
tables, which are intolerably slow in the worst case.  And the compiler
designer often doesn't do any analysis to determine the probability of
that happening.  Just wait until somebody complains, and then fix it.

But I still don't want to trust a conservative GC, at least not for any
program that is supposed to be reliable.

- Bob