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From: cottrell@nbs-vms.ARPA
Newsgroups: net.lang.c
Subject: old computer noises
Message-ID: <7835@brl-tgr.ARPA>
Date: Tue, 29-Jan-85 19:08:35 EST
Article-I.D.: brl-tgr.7835
Posted: Tue Jan 29 19:08:35 1985
Date-Received: Sun, 3-Feb-85 00:14:27 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 19
Xref: seismo net.lang.c:4185

The way I understand it, everytime the cpu references memory it
generates radio waves on ALL (lotsa) frequencies. The tones you hear
are audio frequencies modulating the RF carrier. There are certain
instruxions that in the degenerate case will copy from a register
to a register repeatedly, in effect doing nothing, but as a side
effect waiting a given amount of time before referencing memory again.
Your program has two tables, one for the notes themselves (period
not frequency), and one for the duration (depends on the period).
The program picks up the first note & duration pair, loads a repeat
count register with the period, does the funny loop duration times.

Is this what you did, or am I way off base?

By the way, I once wrote a program to make a high speed tape drive
play a musical scale by writing successively shorter records one 
hundred times each. The records were 1000, 800, 600, 700, 500, 400, 300, & 200
16 bit words. Obviously this mechanical system is not as linear as
the electrical memory reference one is! 
*/