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.