Odd floppy drives (Helitron)

[Fred Cisin]

On Sat, 24 Sep 2005, Scott Stevens wrote:
> The oddest 'floppy' drive that I ever saw was a dictaphone machine that
> recorded by cutting helical audio tracks like a phonograph record on a
> thin 'floppy' plastic disk.  Ooops, it wasn't digital (unless you held
> it in your fingers).

<nitpick>
grooves "like a phonograph record" would be "SPIRAL", NOT "helical".
"Helical" would be like a spiral stair case, or threads on a bolt.
Some of the early (Edison?) sound recorders DID cut helical threads on the
outside of a cylinder.
</nitpick>