Odd floppy drives (Helitron)
hilpert at cs.ubc.ca
Sat Sep 24 22:51:35 CDT 2005
> 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).
... that would be (or describes) the Gray 'Audograph', made by Northern
Electric (at least in Canada, perhaps by Western Electric in the US).
Circa mid-1940s. The disc is 6.5 in. diameter, holding one reminds one very
much of a bare floppy removed from it's envelope: similar weight (floppiness),
except it's a translucent deep-blue.
(Yes, I do have one (the recorder/player and several blank discs)).
Fred Cisin wrote:
> 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.
Well, the tracking is performed by a helical-thread drive mechanism :)
Actually it's a little unusual in that (in contrast to record players and disc
drives) the head/needle is stationary and the disc is moved 'radially' (as well
as rotating of course).
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