Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!husc6!rutgers!ames!ptsfa!hoptoad!academ!killer!sentinel
From: sentinel@killer.UUCP (The Sentinel)
Newsgroups: talk.bizarre,comp.misc
Subject: Re: What the world needs now [ is an exploding computer ]
Message-ID: <913@killer.UUCP>
Date: Wed, 20-May-87 20:30:14 EDT
Article-I.D.: killer.913
Posted: Wed May 20 20:30:14 1987
Date-Received: Sun, 24-May-87 03:36:38 EDT
References: <12067@topaz.rutgers.edu> <910@killer.UUCP>
Organization: A Un*x Box in Texas
Lines: 48
Keywords: Originally from a friend
Xref: mnetor talk.bizarre:1861 comp.misc:575

In article <910@killer.UUCP>, jfh@killer.UUCP (John Haugh) writes:
> In article <12067@topaz.rutgers.edu>, trudel@topaz.rutgers.edu (Jonathan D.) writes:
> > 
> >                                                      Forget artificial
> > intelligence!  Forget relational databases!  Forget distributed network
> > architecture proposal interface protocols!  Forget documentation!  Forget
> > associative memory!  Let's make computers explode in our lifetime!!!
> 
> [...] that one of the unused op-codes
> in the M6800 had the nasty side effect of overloading the bus and causing
> much grief on the PC board the chip was mounted on.  The idea was that this
> illegal instruction repeatedly fetched from the bus at a rate that was more
> than what the bus could handle, and poof! instant meltdown.
> 
> You don't really expect me to believe that this actually happened now do you?
> Anybody out there heard of anything like this really happening?

    Yep.  When I was in high school, we had several SWTPC 6800 machines, of
slightly post-Altair vintage.  They had 32k of RAM (a lot at the time),
5-1/4" single density drives that held around 90k, a CP/M-like operating
system, and you had to boot them by calling the disk boot rom from the
monitor.
    Anyway, I saw demonstrated (not with the school's permission, as you can
probably guess) a program called "DEATH" which did a number of destructive
things including stepping the drives out of range and apparently using this
opcode you mention.  I remember the main board going in for service after
that and coming back with lots of new chips.  I never knew how a program
could do this until now...
    (Don't take everything I said as absolute truth... my memory is a bit
fuzzy... I do distinctly remember the computer being fried by that program,
though.  And no, I was not the one who did that... I was only a spectator)

    On another note, some of the earlier Commodore PET's had a register in
their video controller that set the number of scan lines (or something like
that).  On some of them, you could tweak this register to get a better looking
screen display.  On others, doing so would toast the video circuitry.  While
this is not strictly in the "exploding computer" category, in the PETs the
monitor WAS in the same case, so it has the same effect on the poor guy who
watches it happen :-)

> - John.		(Freddy the Freeloader in Decadent Dallas)

--TS
-- 
Rob Tillotson				...ihnp4!killer!sentinel
3922-1 Newport Ave.				-or-
Fort Wayne, IN 46805			...rutgers!unirot!sentinel
(219) 483-2722				    (top one preferred)