[TUHS] Monitoring by loudspeaker

Tom Ivar Helbekkmo tih at hamartun.priv.no
Sun Aug 23 18:58:19 AEST 2020

Robert Clausecker <fuz at fuz.su> writes:

> When the computer is in a tight endless loop, the accumulator takes the
> same series of values every time it's in the loop.  Thus, instead of
> white noise you get a sound whose frequency is the clock frequency of
> the machine divided by the number of cycles spent by one loop iteration.

A buddy and I did something somewhat related back in the early eighties,
when we were teaching ourselves programming, using, among other things,
his Tandy TRS-80 home computer.  We discovered that a cheap "transistor
radio", sitting close to the computer, would be affected by the noise
generated by it, and then we figured out that if we didn't tune it to a
radio station, we'd get only the noise.  Leaving that on as we worked on
a program, we got familiar with the sound of the code, and became able
to follow the execution by the changing patterns -- and if it did get
stuck in a loop somewhere, we'd not only hear it, but we would also have
a pretty good idea where it happened.

Most people who graduate with CS degrees don't understand the significance
of Lisp.  Lisp is the most important idea in computer science.  --Alan Kay

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