[julian55]

At one place I worked at back in the 1970s there was a speaker on the mainframe (it may have just been a transistor radio picking up interference) and you could get some idea of what the machine was doing from the sound.

[TheOtherHobbes]

That was how the earliest computer music was made. You could play notes with loops that included varying numbers of no-ops to set the pitch.

[k12sosse]

Very Nullsoft Beep.

https://www.1014.org/code/nullsoft/nbeep/