Philipp Hachtmann
1 HN recommender · recommended in 3 months, 2018–2020
4:06 · 50K views · Apr 2, 2008
A 1971 DEC LAB-8/e (PDP-8/e) minicomputer plays music by inducing noise into a nearby AM radio. The software is Richard Wilson's 1975 Music Compiler running under OS/8.
HN cites it as an early example of making a computer emit music over AM radio through electromagnetic side effects.
3 comments from Hacker News
> leaking AM emissions from a computer by twiddling the memory bus This technique is as old as computers themselves, it's well-known back to the mainframe and minicomputer era. For example, here's a video of a DEC PDP-8 (LAB-8/e) minicomputer (1971) playing music using the same technique [0], the software was Richard Wilson's "Music Compiler" written back in 1975, you should watch it. Later it was also rediscovered by the microcomputer hackers, members of the Homebrew Computer Club played Beatles on the Altair 8800. Acoustic leakage is also possible. Here [1] is a program that runs on a Thinkpad, and here's the video [2]. It changes the Intel CPU P-state to induce a coil whine at a specific frequency, and it plays PC Speaker music via the inductor coil on the switched-mode power supply of the CPU. On one hand, we can say it's a time-honored tradition in computing and hacking, on the other hand, it means the same huge side-channel exploit is still here despite that it has been half-a-century already... [0] this video [1] [LINK] [2] [LINK]
I seem to recall reading about this running on minicomputers or mainframes, as described in another reply, and I also think this predated the Altair, as I first became smitten with computers around 1972. Here's a video of a minicomputer generating AM radio music in 1971: this video
Here's a video of a PDP-8/e playing tunes over an AM radio: this video The software dates to around 1975.