Homebrew Drum Computer

[Tony Duell]

> Would a hard drive platter be able to store analog data?  It would be 
> neat to store audio on it like a record.  : )

Yes. Somewhere I have a video hard disk (Jay, this is, IMHO on-topic for 
a reason I'll explain in a moment). It rotates at (IIRC) 50rps (amybe 
25rps), and has a number of fixed heads. A video frame is recorded -- 
analogue FM modulated -- on 3 tracks, one for each of R,G,B. I can't 
rememebr how many sets of heads you haev -- so howm many frames yuo can 
record at once.

The company that meade it really made them for storing the 'action 
replay' images for TV. But mine came wit ha PDP11 interface. It transfers 
a frame of video out of the PDP11's memoey (it hooks up to a DR11-B), 
feeds it into a DAC, then into the FM modulator, and thence to the disk. 
It's one of the more unusual video output systems I have for the PDP11.

-tony