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From: bolosky@wb1.cs.cmu.edu (William Bolosky)
Newsgroups: comp.unix.wizards
Subject: Re: brk's zero-fill behavior on VAXen
Message-ID: <2@wb1.cs.cmu.edu>
Date: Wed, 19-Nov-86 02:53:03 EST
Article-I.D.: wb1.2
Posted: Wed Nov 19 02:53:03 1986
Date-Received: Wed, 19-Nov-86 06:03:24 EST
References: <7208@elsie.UUCP> <5142@brl-smoke.ARPA> <2447@hcr.UUCP> <2486@phri.UUCP>
Organization: Carnegie-Mellon University, CS/RI
Lines: 17
Summary: Some code does rely on new memory being 0'ed


In the process of putting up the Mach VM implementation here at CMU we
introduced a bug which caused newly allocated memory to not be zeroed in
some esoteric circumstances.  This caused malloc to behave incorrectly
(malloc itself, not things using it), at very infrequent intervals.

It's hard to guess just what else relies on this, but I would wager that
there are more things that do...

BTW, On the IBM RT PC the 0 opcode is a jump instruction, and 0000 means
(guess what) "jump to yourself."  This is annoying.
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Bill Bolosky
Mach Kernel Group, Carnegie-Mellon University CSD
ARPA: bolosky@wb1.cs.cmu.edu
BITNET: wb0g@cmcctb.bitnet