zlacker

>>tobr+(OP)
The funniest demonstration that I watched was at the computer museum at the University of Stuttgart (it's just a single room, but it contains a lot of history!). The guide took an old, butchered radio that was reduced to a coil attached to a speaker and put on top of the front panel of a PDP-8. Then he started a Fortran compiler, which would take several seconds to complete. During that time, the radio made kind if hideous digital beeping noises from the CPU's EMV radiation that got picked up by the coil inside. You could easily learn to distinguish different compiler phases and tell whether the program made progress. The guide explained that this was a common way for operators back in the day to keep track of the jobs they were running while taking care of other tasks: were they still running? Did they get stuck? Did the job complete and is it time for the next one? Some inventive guys figured out that when you wrote certain instruction sequences, the EMV noise would become tonal and the pitch could even be tuned to some extent. That got them to write programs which would compute nonsense, but when you picked up the EMV emissions, you would hear music! The museum guide ran a few of these programs to our great amusement :).

I've yet to see this mentioned - or demonstrated - anywhere else.

>>gmueck+PG4
During particle physics experiments, the number of reactions of interest that get detected is an important thing to monitor. If you stop measuring the reaction of interest, it might mean that a magnet drifted out of preferred tuning, that your data acquisition crashed, but the key thing is that something requires human intervention to fix. Frequently, the trigger signal, which has a short pulse anytime data are to be collected, would be sent into a speaker. You get a buzzing, not unlike a Geiger counter at high rates, which blends into the background noise, and that tells you how healthy the experiment is.

The funniest thing was seeing how everybody was paying attention to that buzzing at all times. You could have a dozen people talking about different aspects of the experiment, but if that buzzing drops out for a few seconds, every single conversation immediately stops. Usually it would come back after a few seconds and the conversations would resume, but it was fascinating to have visible proof that everybody was ready to drop their current work in order to get the experiment running again if anything happened.

Edit: I also heard tales of somebody who had trained themselves to wake up if the buzzing ever stopped. That way, they could take short naps during the night shift, while still being present and ready to resolve any issues that came up.