Mr-T <jonthorp@-no-spam-bigpond.net.au> wrote:

> This might sound like a silly question, but is there any aesthetic
> difference between the "SuperDrive" and the standard Apple II 3.5 floppy
> drives?

Assuming you are talking about an external drive, complete with case,
then there is a label on the bottom which should say "Apple 3.5 Drive"
for an Apple 3.5 Drive, or either "FDHD" or "SuperDrive" for a
SuperDrive.  The mechanism can be put in any case, so this isn't
conclusive.

There are no other obvious external differences.  The SuperDrive and
late model Apple 3.5 Drive used the same case, with a yellow LED and a
large lumpy plug on the end of the cable.  Earlier Apple 3.5 Drive cases
used a red LED and a more petite plug.

I've never had a close look at a bare SuperDrive mechanism, so I don't
know if there are any obvious markings such as a part number.
Physically, they are exactly the same size as the 800K mechanism, with
the same connectors and mounting support.

If you can get a close enough look at the mechanism, it may be possible
to distinguish them by looking for the disk presence and state
detectors.

The Apple 3.5 Drive has two detectors near the front of the drive.  One
is used to sense whether a disk is inserted, and the other is used to
sense the state of the write protect selector (so you should be able to
determine its position pretty accurately).  The SuperDrive has an extra
detector, to sense the state of the density hole, which is on the other
side of the disk from the write protect hole.

Earlier drives use a little plastic switch for these detectors: the body
is black, and the switch part is a white post, about one millimetre in
diameter, and a few millimetres long when extended.

Later drives use an optical sensor.  I haven't had a close look at
these, so I don't know what they look like.

I expect that all SuperDrives use an optical sensor, while Apple 3.5
Drives would be a mixture of the two methods.

If in doubt, the most reliable method would be to connect the drive to a
Mac which supports the SuperDrive (or an Apple IIe or IIgs with the
SuperDrive card), and try to access or erase a high density disk.

-- 
David Empson
dempson@actrix.gen.nz