Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!nrl-cmf!ukma!tut.cis.ohio-state.edu!rutgers!mit-eddie!uw-beaver!uw-june!uw-entropy!dataio!pilchuck!ssc!markz
From: markz@ssc.UUCP (Mark Zenier)
Newsgroups: comp.misc
Subject: Re: Looking for Computer Folklore
Message-ID: <1690@ssc.UUCP>
Date: 9 Feb 89 21:48:16 GMT
References: <7143@pyr.gatech.EDU> <532@geovision.UUCP> <4575@tekgvs.GVS.TEK.COM> <911@mailrus.cc.umich.edu>
Organization: SSC, Inc., Seattle, WA
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In article <911@mailrus.cc.umich.edu>, shane@chablis.cc.umich.edu (Shane Looker) writes:
> That (in turn) reminds me of the early 6502 chips (used by the Commodore
> PET).  Supposedly, some of the first series used in the PET had an
> actual HACF (Halt and Catch Fire) instruction.  I've been told that
> one instruction would cause all the pins to fire at once, thus burning
> out the chip.
> 

Er, Halt and Catch Fire (as I remember it) came from the days when
people were delving into the undocumented opcodes, one such seeker
after truth (as documented in Dr. Dobbs and or Byte) found a couple of
interesting instructions on the Motorola 6800.  One was store immediate,
and another was dubbed HCF.  When this opcode was executed, the cpu
would fetch bytes continuously (all 64k bytes), forever and
the only way to stop it was turn the power off.

Mark Zenier    uunet!nwnexus!pilchuck!ssc!markz    markz@ssc.uucp
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