[no subject]

    In comparison, a High Density 3.5" diskette can and will format in a
single/double density 3.5 drive (eg, standard Macintosh Plus, Apple IIgs, 
Amiga 500, Atari ST, IBM AT/286's). The magnetic coating doesn't seem to
differ in that sense, although the _quality_ of the disk surface or that 
coating may. It is not recommended you do this (or visa-versa, by punching
a notch to make a double density 3.5 function as HD) but this is debatable.
Rumour has it that double-density 3.5 diskettes, are merely HD disks that
did not pass high quality testing (in otherwords, decent enough where it
will be reliable holding more sectors per track). This would explain the
HD notch imprint might you find on some double-density 3.5 floppies. :)

>Any such drive would also need a special controller, and is not likely 
>to support standard Apple II disks.

    The BlueDisk controller card is such an example, it allows an Apple II 
to interface with a PC 5.25 drive and format 1.2MB floppies. Of course as 
most PC drives are internal, you would require an external casing and power
source for the drive (or have a "towerized" Apple II). Personally, other
than compatibility sake with 8-bit Apple II's, I find 5.25 diskettes a pain
and otherwise useless. They're too large to carry around and can damage
easily, unlike 3.5 diskettes which have a hard protective shell and metal
dust shutter.

    That's correct, GCR encoded disks cannot be read or created by a
PC drive connected to a BlueDisk (or real PC). However, you should be
able to format ProDOS diskettes in MFM formats, such as 360K and 1.2MB.
They of course will not be readable by any Apple II, unless they too
have a BlueDisk setup.

Mitchell Spector
spec@vax2.concordia.ca