How does he do that stuff?
Obviously you need a small Microcontroller and communication line of your choice to your computer. (USB or RS232 or the most common ones)
The next part that you need the pin configuration of the floppy cable, understand the functions of these pins and now your are able to write
down your own floppy disk drive printout and with this you can control the induction motors of the floppy drive.
Now theres a tricky part. Now you need a state machine which converts your incomming data stream which is send from the computer to your microcontroller over your communication line into corresponding movements which generate your music. (With more Floppy drives your music
sounds nicer, in the youtube video there were 8 floppy drives)
At least the most tricky part is the data convertation, due to the limited bandwith/speed/accuracy of the induction motors of the floppy drives your not
able to convert the 44.1kHz/16Bit music stream into a good sound.
