Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!mailrus!tut.cis.ohio-state.edu!husc6!cca!mirror!prism!billc
From: billc@prism.TMC.COM
Newsgroups: comp.arch
Subject: Re: Computer noises (was Re: Cray a
Message-ID: <208300001@prism>
Date: 2 Apr 88 00:01:00 GMT
References: <1503@vaxb.calgary.UUCP>
Lines: 34
Nf-ID: #R:vaxb.calgary.UUCP:-150300:prism:208300001:000:1802
Nf-From: prism.TMC.COM!billc    Apr  1 19:01:00 1988


-> The Radio Shack TRS-80 Model 1 (a personal computer before PC meant
-> IBM) put out enough RF interference that it became popular among
-> TRS-80 hackers to put a small radio next to the machine to listen to
-> what it was doing. Some people tried to program them to play music
-> this way...
-
-I have a vague recollection back from when I was a first-year student
-(1974) of someone demonstrating a program for the PDP-8 that played a quite
-good rendition of some piece of music on a radio placed beside the 
-CPU. In retrospect, this seems moderately unlikely, though not impossible.
-Does anyone know whether such a program existed? Whether it was feasible?
-I believe the machine had core memory, would that have helped?
-
-If it existed, it must have been some hack... I recall the music lasting
-at least 10 seconds, good enough to require 6K samples/second minimum, say
-6 bits per sample, doesn't look like it fits in 4K 12-bit words... Maybe
-I was duped... Then again, the machine did have a disk...
-
	I don't doubt that someone programmed that. When I first got
	into computers, there was a little kit computer called the
	Altair 8800 (I think) that ran an 8080 processor (This was 1975
	or so.)  I heard the thing play "Daisy" through an ordinary AM
	radio, by running a relatively short assembly language program.

	I beleive that the way it worked is that some fairly standard
	instruction gave out a strong RF pulse.  The program consisted
	of nested loops of proper lengths and some simple controls to
	make the pulses come out as desired so that the radio could pick
	it up.

Bill Callahan	voice: 617-661-0777, ext. 149
Mirror Systems	2067 Massachusetts Avenue  Cambridge, MA, 02140
	billc@mirror.TMC.COM
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