Blowing up monitors with assembler
Ad absurdum per aspera
>Today me computer teacher told us that in the early days of
>computing some of the first PC's and thier monitors had a neat
>feature. He claimed that you once were able, through advanced
>assembly techniques, to catch the monitor on fire. Truth or
>computer legend?
(a) PC's are not from "the early days of computing," unless
perchance you have an awfully young teacher.
(b) I heard a version of this tale at a bull session at
the modem company where I used to work. The exact
machine and terminal escape me now, though in the best
tradition of both documentation an urban legend, both
were specified. I think that the mechanism was filling
the entire screen with whatever the character is that
lights up all the allotted pixels, which supposedly drew
current beyond the maximum credible load allowed for by
the designer of some part of the hardware (possibly in the
sweep circuit), eventually causing smoke to come out.
This was referred to as the "Halt and Catch Fire" function.
The person who told the story was not a hardware engineer
(but he knew someone who was), and we'd all enjoyed many a
brew, and it was several years ago, so it is not surprising
that I can neither remember nor reconstruct the physical
details. Surely someone here would know...
Joe
"Just another personal opinion from the People's Republic of Berkeley"
Disclaimer: Even if my employer had a position on the subject,
I probably wouldn't be the one stating it on their behalf.
Ray Depew
: Today me computer teacher told us that in the early days of computing some
: of the first PC's and thier monitors had a neat feature. He claimed that
: you once were able, through advanced assembly techniques, to catch the
: monitor
: on fire.. Truth or computer legend?
I once had an HP9816 and a bad OS on disk. Every time I tried to boot the
system using the bad OS, the speaker would warble loudly, the display would
draw an extremely bright Lissajous pattern, and then the whole system would
lock up, dark and quiet. Being the stupid new engineer that I was, I kept
trying to boot with the bad OS, until I fried/burned up a power FET in the
display HW. Didn't catch fire, but the poor FET did lose all its smoke.
The repair tech said "How'd you do that? You're not supposed to be able
to do that!" I'm so talented ...
BTW, for anyone who cares, the HP 9816 was about the same size and shape
as the original Apple Mac, used the same CPU and a similar display, had
a better OS (actually a choice of OS's) and actually predated the Mac.
It even ran VisiCalc and Context MBA. It would have been the world's
standard for The Other Kind Of Computer if the particular HP division
in charge of it had had a good marketing department at the time.
Regards
Ray Depew
the undead ex-Executioner
r...@fc.hp.com
"When your Daemon is in charge, do not try to think consciously.
Drift, wait and obey." -- Rudyard Kipling
Eric Valentine
> Brian Baltzell (ga...@matt.ksu.ksu.edu) wrote:
>
> : Today me computer teacher told us that in the early days of computing some
> : of the first PC's and thier monitors had a neat feature. He claimed that
> : you once were able, through advanced assembly techniques, to catch the
> : monitor
> : on fire.. Truth or computer legend?
>
> I once had an HP9816 and a bad OS on disk. Every time I tried to boot the
> system using the bad OS, the speaker would warble loudly, the display would
> draw an extremely bright Lissajous pattern, and then the whole system would
Every use a Hecules board? I don't mean Hercules, either. They were made by
the __________ Corporation (I think whoever sold them was supposed to fill
in their name) and came with the most inscrutable instructions
I've ever seen, like "Very Register programming find address not $2BD0." When
used with the _______ monitor they would make a startling POP when going in
and out of Hercules, sorry, Hecules mode. All new video routines were tried
out with one hand on the power switch to avoid phosphor-grill syndrome.
________ __ ___ _______ ___________________ _ ___________
/ <sig under construction> /
/ Eric Valentine
/ <will be site of opinion/employer relation statement>
/ <witicism space available> SAFETY FIRST! /
/_______ ___ __________ _ _____ ___ ______ ________/
Stephen Payne
users at school. You would just tell them to wait for a keypress and then
send the tape on/off relay whizzing and make aound and flash the screen.
The great thing about the BBC also was that you could make it do this
forever using ONERRORRUN and *key10 - providing they didn't do a ctrl-brk.
I also heard of hard drive racing, where you had a huge (very old) hard drive
about the size of a washing machine and you got it to move the heads slowly
to the end of the disk and the quickly back.
The last thing worth of note is getting an old tape driven system or two and
having the end of the tape fixed - this way you can race these guys too!
---
* ^ ^ * Stephen Payne
* + + * pa...@meiko.co.uk
* '` * "When in darkness or in doubt,
* |____| * run in circles, scream and shout."
* * Disclaimer: I do not speak for Meiko...Only for God
Helge Moulding
: Brian Baltzell (ga...@matt.ksu.ksu.edu) wrote:
: : [hoary story about PC killers as told to some callow youth by a
: : young whippersnapper went here...]
: [Ray admits discovering the rule "if you diddle often enough,
: you'll eventually get diddled back." Let's here lot's of "me,too!"
: stories, please!]
: [Then he waxes poetic about YADPOCH (yet another defunct piece
: of computer hardware), and concludes with the following Words
: of Wisdom (TM):] It would have been the world's
: standard for The Other Kind Of Computer if the particular HP division
: in charge of it had had a good marketing department at the time.
Can anyone name a company - including IBM - which did *not ever* have
a piece of hardware (or software, FTM) for sale about which the
above statement would have been true; i.e. "it would have been the
world's standard if marketing had pulled their head out"?
BTW, there have been not a few instances were individuals frustrated
with the incidence of stolen software threatened to write code to
detect illegal copies and destroy any hardware on which the illegal
copies were found. Some instances may even actually exist.
--
Helge "If they had marketed it properly, pen and
paper would be the world's standard for word processing" Moulding
(Just another guy with a weird name)