Date:	Fri, 21 Nov 1997 14:37:48 +1300
From:	physmsa AT cantua DOT canterbury DOT ac DOT nz (Mr M S Aitchison)
Subject:	Re: rodent problems
To:	opendos AT delorie DOT com
Message-id:	<199711210137.OAA11710@cantua.canterbury.ac.nz>

Long before OpenDOS came, I have discovered that *sometimes* loading a
mouse driver high causes all manner of problems.  I suspect that is
what is happenning here (since usig HIMEM instead of EMM386 fixes
it).  Symptoms I have found include system hangs, memory control block
messed, mouse not working except under Windows (since it has its own
driver) and interference with networking.

I have never found why, exactly. And I don't know which combination of
O/S, mouse driver and other software causes, but you can sometimes make
a minor change in the order things are loaded and it can work. It is
probably a situation where the mouse driver can write over memory
outside its area, and it is a matter of where things are loaded that
determines whether this matters a lot or not.

I find it is a good idea when anything happens involving the mouse, or
that indicates any instability, to start by not loading the driver
high, and see if that fixes it.  If so try a few alternative mouse
drivers and check you aren't using any upper memory regions you
shouldn't.


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Mark Aitchison,                 \_   Phone: +64 3 364-2947 home 337-1225
Dept of Physics & Astronomy,    </     Fax: +64 3 364-2469  or  364-2999
University of Canterbury,      /)   E-mail: phys169 AT csc DOT canterbury DOT ac DOT nz
Christchurch, NEW ZEALAND.    (/'     www.phys.canterbury.ac.nz/~physmsa
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