Back in the early days of digital computers, engineers would often troubleshoot
hardware by writing "musical software." Portable AM radios would be used as "sniffers"
in circuit areas where tubes and/or relays would be turning on and off with rhythms
that were determined by the test software. If the chosen familiar tune did not sound
as it should, then the problem could be deduced to be associated with that area
of the processor known to be controlled by the program.