On: Prince of Persia source code released (Apple II as...

[Someone]

I think you will be interested in the design of the Macintosh video/audio hardware, too, then; http://www.folklore.org/StoryView.py?story=Sound_By_Monday.t... gives some details.

IIRC, things were even better. There were two (740 byte, IIRC) buffers from which samples were taken at every horizontal refresh.

The sound driver used one to get samples to send to the speaker; the disk driver used the other to control the rotation speed of the disk drive (using pulse-width modulation).