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From: ballard@cheddar.ucs.ubc.ca (Alan Ballard)
Newsgroups: comp.os.os2.misc
Subject: Re: Parallel Port in OS/2 1.2 or 1.3
Message-ID: <1991Mar16.231649.1569@unixg.ubc.ca>
Date: 16 Mar 91 23:16:49 GMT
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In article <gah.669092867@hood> gah@hood.hood.caltech.edu (Glen Herrmannsfeldt) writes:
>... If the port does not have an interrupt line
>connected, then it will probably work with DOS and not OS/2.
>Now, it really should, because the IBM PC, which it should be
>compatible with, does.  Then again, it may be jumper selected.

The earliest PC's had a design flaw in the interrupt design of the parallel
port, such that it didn't work reliably.  I think this was corrected around 
the time of the AT, but some clone manufacturers may have continued to the
original spec's.  Don't remember any details, but I think it had to
do with working with level-triggered interrupts (as used in DOS, when
it uses interrupts at all), but not working with edge-triggered, used by
OS/2. 


Alan Ballard                   | Internet: ballard@ucs.ubc.ca
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