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From: ntitley@zaphod.axion.bt.co.uk (nigel titley)
Newsgroups: comp.misc
Subject: Re: Looking for Computer Folklore
Message-ID: <1069@zaphod.axion.bt.co.uk>
Date: 14 Feb 89 21:46:04 GMT
References: <911@mailrus.cc.umich.edu>
Sender: news@axion.bt.co.uk
Reply-To: ntitley@zaphod.axion.bt.co.uk
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From article <911@mailrus.cc.umich.edu>, by shane@chablis.cc.umich.edu (Shane Looker):
> In article <1373@umbio.MIAMI.EDU> aem@Mthvax.Miami.Edu (a.e.mossberg) 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.

This  was  actually  true  of  the  early 6800s  (not 6502)  which had  some
unassigned OP Codes. If you tried to execute one of  these instructions  the
chip went into a tight microcode loop which  overheated a  small section  of
the microcode ROM. It was this that burned out the chip.

Nigel Titley

Email: NTitley@axion.bt.co.uk
Snail: British Telecom Research labs, Martlesham Heath, Ipswich, Suffolk, UK
"Well, I'm disenchanted too. We're all disenchanted." (James Thurber)