USB 5.25" floppy drive - do it

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Jun 11 18:01:19 2004

> Plus I'm not sure how the raw data stream is clocked (rather, I have the
> info here, I just can't remember without going to look it up). If the
> floppy drive just starts spewing out raw data on a read but the clock is
> handled at the host side then I might have problems there...

That's exactly what happens. Well, some 8" drives have single-density
data separators built-in (this is the circuit which decodes the raw
bitstream from the head amplifier into clock and data pulses), but don't
bet on it, and don't expect it to work for double-density (MFM) data. And
I've never seen a 5.25" or 3.5" drive with a data separator built it.

I suppose what you really want is the equivalent of a the Catweasel (a
device which records the raw data stream from the read amplifier and lets
software figure out what it means) with enough buffer memory to hold 1
track of data, and an Unusable Serial Botch interface..

-tony
Received on Fri Jun 11 2004 - 18:01:19 BST