Re: 3.5: drives

[david@wraith.its.uow.edu.au (David E A Wilson)]

Jim.Low@logicbbs.org writes:
>A few years ago, I picked up an unusual 3.5" drive at a garage sale that was 
>designed for the Apple II.  It was a single sided, 320k drive.  It came with 
>it's own controller card.  It also worked with the standard Disk ][ 
>controller -- but only as a 160k drive.  It came with it's own patched 
>version of ProDOS.  It was called a "Shamrock."

This reminds me of one of the 5.25" drives on my clone //e. It is a standard
1/2 height drive with an adapter card to allow a Disk ][ controller (or clone)
to run it. It uses the track zero sensor to stop it banging its head at boot
or on read errors. A modified version of such a card attached to a 3.5" drive
would allow 320k easily (80 tracks, one side) or 640k with a little more
difficulty (either using the drive select as a head select or odd/even track
numbers as the head select and only stepping on every second track). Given
that this would work with existing controllers I think it would have sold
well back when 3.5" drives for PCs first became cheap. Probably a little late
now.
-- 
David Wilson	Dept CompSci Uni Wollongong Australia	david@cs.uow.edu.au