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From: folta@tove.umd.edu (Wayne Folta)
Newsgroups: comp.sys.ibm.pc,comp.sys.mac
Subject: Re: Multiple monitors (was: Xerox sues Apple!)
Message-ID: <21548@mimsy.umd.edu>
Date: 30 Dec 89 18:59:00 GMT
References: <2938@infmx.UUCP>
Sender: news@mimsy.umd.edu
Reply-To: folta@tove.umd.edu (Wayne Folta)
Distribution: usa
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
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[Referring to two monitors on an IBM AT:]
>Tough to configure, too.  Open the machine, add the mono card, screw it in,
>close the machine, turn on the power.  No switches to set, no muss, no fuss.
>To switch primary monitor to the mono, run "mode mono".  To switch back to 
>EGA, run "mode co80".  To enable the secondary monitor in the Informix-4GL
>debugger (for example), run "appl dev" (application device enable).
>Gee, that didn't hurt a bit.

I don't think it is so easy to do this in general.  Your Mono/color system
is pretty easy.  What about a multi-color system?  How would you change
monitors then (co80a, co80b?)?  And when you do change monitors, you have to
give a special command.  On a Mac, you simply move the cursor to the screen
you want (you define the geometry: how the two monitors logically abut).

I am speaking from gross IBM ignorance--I have no substantial IBM experience,
I mainly watch IBM-using friends.  But, I have just watched a friend attempt
to get an internal modem to work with his other cards... How he wasted hours
with DIP switches and jumpers.  Are monitors that much easier?

I owned an original PC, and I know they were designed for a co80/mono system,
but I wonder what magic you would have to do to get an arbitrary combination,
and how easy it would be to switch.  (CONFIG.SYS time?)

A desktop publishing magazine I read did a test to prove a point: they got
a dozen Mac monitors and randomly chose combinations of five monitors, put
their boards in a Mac II, and booted the thing.  They all worked.  Of course,
no one would use five monitors, but the point was that NuBus cards are
self-configuring and are compatible.  You don't change jumpers, worry about
interrupt levels, edit system configuration files...  IBM has moved in this
direction with its MCA, I believe.
--


Wayne Folta          (folta@cs.umd.edu  128.8.128.8)