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From: jsims@vuse.vanderbilt.edu (J. Robert Sims)
Subject: Re: Serial ports and mice
Message-ID: <1991Jun13.215259.1883@vuse.vanderbilt.edu>
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Organization: Vanderbilt University School of Engineering, Nashville, TN, USA
References: <1991Jun10.153842.12545@midway.uchicago.edu> <1991Jun12.180219.15756@cunixf.cc.columbia.edu> <0094A069.21705FC0@MAPLE.CIRCA.UFL.EDU>
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Date: Thu, 13 Jun 1991 21:52:59 GMT

In article <0094A069.21705FC0@MAPLE.CIRCA.UFL.EDU> sorrow@oak.circa.ufl.edu writes:
>I have two serial ports and just installed a Logitech MouseMan.  Not
>a problem at all.  Modems and COM ports fight over addresses, whereas
>a bus mouse creates its own (yeah, yeah, simplistic but close enough).
>
>Anything that needs COM port when installed or when software is run (such
>as a modem, digitizer, external mouse, etc.) can cause problems.
>
>Bus mice tend to be fairly automatic with installation (no need to say
>which com port, since they don't use one.)
>
>Brian
>/*
>Brian Hook -- MS-DOS Programmer for Contract
>-----------------------------------------------------------------
>"I was in the kitchen, Seamus, that's my dog, was outside....and buried
>ALIVE....fritter and waste...but this one goes to 11!....anymore of that
>plutonium nyborg?...Little guitars..This is home...this is Mean Street..
>*/

This isn't quite accurate.  Bus mice use interrupts.  Sometimes you have
an available interrupt (such as 5), but if you have a network card or
second parallel port, etc. it is likely that you don't have any free
interrupts.  So, the interrupt setting on the mouse card works best on...
Interrupts 3 and 4!  Sure it conflicts with the serial ports! (but not
as badly as the mouse would conflict with an ethernet card, scanner,
whatever).  This interrupt sharing should not be a problem, except that
most mouse drivers are very unfriendly about sharing.

Rob