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From: softeng3456@netscape.net (soft-eng)
Newsgroups: 
 comp.lang.java.advocacy,comp.object,comp.lang.ada,comp.software-eng
Subject: Re: Quality systems (Was: Using Ada for device drivers? (Was: the Ada
 mandate, and why it collapsed and died))
Date: 16 May 2003 18:55:19 -0700
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Date: 2003-05-17T01:55:20+00:00
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"Robert I. Eachus" <rieachus@attbi.com> wrote in message news:<3EC539FA.1040500@attbi.com>...
> soft-eng wrote:
> 
> > Other times are when the bug is very intermittent
> > and cannot be duplicated and you have to proceed
> > blindly, based on theories that are sometimes half-baked.
> 
> We call those Heisenbugs.  Converting a Heisenbug to a Bohrbug that you 
> can reproduce is often the first part of fixing the problem.

GC has made a class of these "Heisenbugs" go away that used to
result from dynamic memory management issues.  But it can add some
very mysterious bugs of its own -- e.g. if you use weak references,
and if a bug results from a logical error in there, it can be
extremely hard to reproduce.