Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!bbn!rochester!cornell!batcomputer!itsgw!nyser!cmx!billo
From: billo@cmx.npac.syr.edu (Bill O)
Newsgroups: comp.sys.ibm.pc
Subject: Re: How did this program burn out two monitors?
Message-ID: <504@cmx.npac.syr.edu>
Date: 24 May 88 05:24:03 GMT
References: <10244@agate.BERKELEY.EDU>
Reply-To: billo@cmx.npac.syr.edu (Bill O'Farrell)
Followup-To: comp.sys.ibm.pc
Organization: Northeast Parallel Architectures Center, Syracuse NY
Lines: 29

In article <10244@agate.BERKELEY.EDU> willis@violet.berkeley.edu (Willis Johnson) writes:
>I recently compiled a program that is supposed to do graphics on 
>a Hercules graphics adapter.  I've used a similar routine before,
>and I would have sworn there was nothing wrong with the software.
>	willis@violet.BERKELEY.EDU

There is a good chance that the program changed the system bits that
control the scan rate of the signal going to the monitor.  In my
(limited) understanding of these things, I believe that software can
select either 50 or 60 Hertz scan rates.  I have definitely heard that
putting the wrong scan rate into a monitor can cause it to burn-out
(complete with smoke, sound effects, even fire) -- some people have
managed to do it by accident just by poking around in memory.

One (expensive) way to insure yourself against this is to buy one of
the so-called multi-synch or multi-scan monitors -- the kind that
switches scan rates automatically to match the incoming signal.
The watch word here is *automatically*. If the scan rate is changed
by a switch on it somewhere, there's no protection. Better check
the specs carefully if you contemplate actually buying one of
these things.

Alas, this is another example of how seemingly harmless computer
hardware can potentially injure people. Over the years there have been
igniting tape-drives, ballistic disc drives, radiation hazards, toxic
chemicals, and other dangers. Maybe your should submit your experience
to comp.risks.

Bill O'Farrell, Northeast Parallel Architectures Center at Syracuse University
(billo@cmx.npac.syr.edu)