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Path: utzoo!attcan!uunet!lll-winken!lll-tis!lll-ncis!lll-lcc!ames!mailrus!wasatch!cs.utexas.edu!oakhill!bryant
From: bryant@oakhill.UUCP (Bryant Wilder)
Newsgroups: rec.music.synth,comp.sys.next
Subject: Re: NeXT!
Summary: real time
Message-ID: <1604@oakhill.UUCP>
Date: 22 Oct 88 06:43:29 GMT
References: <881019-085756-6643@Xerox> <1127@leah.Albany.Edu> <2881@sugar.uu.net> <3284@utastro.UUCP>
Organization: Motorola Inc. Austin, Tx
Lines: 25

In article <3284@utastro.UUCP>, james@utastro.UUCP (James McCartney) writes:
>   Which brings up a subject -- How was the NeXT music demo done (it was real
> time) ? and, What techniques does one use to implement real time operations
> in Mach or Unix ?


the NeXT demo with the violinist was done in real time using a program
written by the NeXT engineers for the Motorola DSP56001.  there was some
question in my mind whether the general audience realized this.  in fact
steve came out after he had finished the intro and we talked about 
it.  since he didn't have time to explain that it was being done in real
time (the stage was torn down immediately at 12:00 noon), he figured many
in the audience might think it was recorded.

the real time sound doesn't interfere with the operating system once the
DSP56001 program is started.  the 56001 programs can be downloaded from
the disk or from the operating system memory or even via the 56001's 
serial ports.  the next machine provides the 56001 with 8K of static ram
on the 56001's own address and data buses.  the output sound digital data
is outputed serially to the d/a converters located in the monitor and then
to the output jacks.

bryant wilder 
dsp operations manager
motorola 
austin, texas