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From: einhorn@triton.unm.edu (E Drew Einhorn ADV.SCI.Inc)
Newsgroups: comp.unix.aux,comp.sys.mac.misc,comp.sys.mac.hardware,comp.sys.mac.system
Subject: Re: MIDI Under A/UX
Message-ID: <1990Sep18.174952.2672@ariel.unm.edu>
Date: 18 Sep 90 17:49:52 GMT
References: <1990Sep18.015919.13846@julius.cs.uiuc.edu>
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Organization: University of New Mexico, Albuquerque NM
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In article <1990Sep18.015919.13846@julius.cs.uiuc.edu> totty@flute.cs.uiuc.edu (Brian Totty) writes:
>
>	I have a MIDI interface that we have plugged into a Mac II serial
>	port which we can access under the Mac OS which we want to access
>	under A/UX.  To generate MIDI speeds, it is necessary to set some
>	serial communications controller registers to tell it to expect
>	an external clock and use different dividers.  We have Mac OS code
>	to do this.
>

Please let us posted on your progress.

Before investing too much effort in your MIDI A/UX I would suggest
experimenting with a very simple protocol, a single message type and an
echo.  Measure the average delay and possibly even more important the
standard deviation of the delay.  After all A/UX does not claim to be a
real time unix.

Some people believe that general purpose computer with a single user OS
needing to update the screen and keep track of the mouse and keyboard
introduces unacceptable timing irregularities and recommend dedicated
sequencer hardware.  (An extreme position).  But A/UX based MIDI
software is a BIG step in the opposite direction.
--
 einhorn@triton.unm.edu