Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!watmath!watcgl!gswan
From: gswan@watcgl.waterloo.edu (Geo Swan)
Newsgroups: comp.os.minix
Subject: Re: Device drivers damaging HW
Summary: All IBM monitors are vulnerable
Message-ID: <10841@watcgl.waterloo.edu>
Date: 27 Jul 89 21:53:14 GMT
References: <13679@ea.ecn.purdue.edu> <4697@omepd.UUCP>
Reply-To: gswan@watcgl.waterloo.edu (Geo Swan)
Organization: U. of Waterloo, Ontario
Lines: 22

>In article <13679@ea.ecn.purdue.edu> jel@ecn.purdue.edu (Jim Lumpp) writes:
>>
>>I am not very familiar with IBM peripheral hardware and was 
>>told it is possible that the drives and monitor of a PC could 
>>be damaged by incorrectly written device drivers (i.e., by 
>>having students write them).  Is this true?  How susceptible 
>>is the IBM hardware to such damage?

Other people have posted followups warning that the CGA and hercules
graphics cards are vulnerable.  I can confimr that the EGA and VGA
are vulnerable as well.

I have a copy of the "Programmer's guide to the EGA/VGA" here.
The following is a quote from the second page of the chapter
describing the control registers for the EGA (of which the
VGA is a superset):

       "... In fact, some of these registers can be absolutely
	dangerous to modify.  Many popular displays will
	literally burn up if driven with improper timing for
	any length of time as a result of improper register
	settings."