(YouTube link)
OK, I don’t know how it’s done and I can’t find any technical information behind it, but apparently you can play music on a floppy disc with a stepper motor. I found a link to this post in the comments at VideoSift that might makes some sense to those who have more expertise than I do. -via VideoSift
If you listen to 'Nude' again ( http://www.youtube.com/watch?v=pmfHHLfbjNQ )you'll hear that this sounds more like the printer or the scanner (both of which use stepper motors) than the HDD array.
Otherwise, bleh to nerdy
Holy smokes, dude. That was effin brilliant, no matter how "bad" it sounded.
In the scanner, its stepper motor is directly driven by the micro (with a driver IC of course), and can directly pout any frequency it wants on the motor.