On 9/24/2005 at 9:52 AM Fred Cisin wrote: 
  Well, I'm holding one of the diskettes in my hand
right now--it's labeled
 2.8" and has no shutter over the access holes.  The hub is a hunk of white
 plastic (nylon?) about 3/4" in diameter with about a 1/4" center hole and
 a very small hole for an indexing pin.  These are "flippies"--each side
 has its own write-protect punchout tab. 
If I remember correcty, these were used in some musical equipment too -
the Korg SQD-1 sequencer and the Akai MD280 disk drive for the S612
sampler.  I believe they used more conventional head positioning, but I
could easily be wrong.
Stupidly I passed up the chance to buy an S612 and MD280 a few years ago,
when a music shop near me had one for ?100.  They're not fantastic
samplers but they were very unusual.
Gordon.