From mboxrd@z Thu Jan  1 00:00:00 1970
From: tih at hamartun.priv.no (Tom Ivar Helbekkmo)
Date: Sun, 23 Aug 2020 10:58:19 +0200
Subject: [COFF] Monitoring by loudspeaker
In-Reply-To: <20200712145822.GA72854@fuz.su> (Robert Clausecker's message of
 "Sun, 12 Jul 2020 16:58:22 +0200")
References: <20200711203020.GA1884@minnie.tuhs.org>
 <202007120222.06C2MtdJ140032@tahoe.cs.Dartmouth.EDU>
 <738ab925-586b-4921-b891-a4ec20348d4c@localhost>
 <20200712145822.GA72854@fuz.su>
Message-ID: <m27dtpu4b8.fsf@thuvia.hamartun.priv.no>

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.

-tih
-- 
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