cvs commit: src/sys/kern subr_param.c

Poul-Henning Kamp phk at
Mon Nov 8 11:25:20 PST 2004

In message <20041108191905.4D47B5D04 at>, "Kevin Oberman" writes:

>> > Can we play music by modulating the value of hz? :)
>> I remember some code for the Commodore Pets that you could use to play
>> notes on a nearby radio by tweaking some spinning loops. Quite a neat
>> trick at the time since there wasn't any sound hardware.
>Actually, this technique predates the PET by any years. I know that we
>could play music on the PDP-1 and that goes back to the late '05s or
>early 60's. I did it on my PDP-11 in the early '70s. I also heard a CDC
>MASStore tape system played as an organ by adjusting the tape movement
>in the vacuum columns.

The first danish computer (DASK) built in 1956... had a loudspeaker
connected to a bit in one of the registers and music were played
as a demo.

The successor (GIER) has a simulator which also simulates the similarly
attached loudspeaker:

I have so many computers with PCI slots running without a lid in
my basement that the commercial "FM100" station can't be received
in a 20m radius around my house...

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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