When you powered up an Apple II, it would make a short beep sound to let you know that it was alive. We thought that the Mac should do something similar, once it passed the diagnostics, sort of like an infant’s first cry, letting the world know that you actually made it here.
The 1981 Macintosh just had a square wave sound generator, where the software controlled the frequency by loading a value into the VIA’s timer. I wrote a boot sound routine that gradually incremented the frequency at an accelerating pace, so it had a whooping quality to it that was almost humorous. People generally liked it, but we knew that we’d have to do something better for the real product.
In August 1982, the Mac was redesigned with much better sound quality, so we had the possibility of a better boot sound, since we now had 8-bit samples to play with. I started experimenting a little bit, to see if I could come up with something.
Boot Beep – The story of the Mac’s boot chime, with source code