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From: ath@helios.prosys.se (Anders Thulin)
Newsgroups: comp.misc
Subject: Re: Looking for Computer Folklore
Message-ID: <345@helios.prosys.se>
Date: 8 Feb 89 08:33:58 GMT
References: <1000@taux01.UUCP> <7449@csli.STANFORD.EDU>
Organization: Programsystem AB, Linkoping, SWEDEN
Lines: 25

In article <7449@csli.STANFORD.EDU> jkl@csli.UUCP (John Kallen) writes:
>In article <1000@taux01.UUCP> taux01!cyosta@nsc.UUCP ( Yossie Silverman ) writes:
>> [... listening on core memory through radio...]
>
>I recall being shown a PDP-8 in Uppsala University two years ago. It
>had a program that would perform memory accesses so as to generate
>noise that could be picked up by an AM radio. I was most amazed to
>hear a *polyhonic* version of "The Entertainer" come from a PDP-8 :-)
>

The DataSAAB D21 computer (RIP) had a loudspeaker attached to one of
the bits in its `multiplicator register'. This gadget made it possible
to play tunes by writing suitable programs.  One such program I
remember played a tune through the loudspeaker while 'stomping' with
the Potter 1" tape stations.

It was also possible to hear on the 'tune' if a compilation succeeded
or not. Just prior to printing out error messages on the line printer
the compiler used to make a sound slightly like a raspberry - that was
a sure sign that there were errors in the code.
-- 
Anders Thulin			INET : ath@prosys.se
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