Mary Sumner's Mac has a SuperDrive (reads up to 1.4 MB floppies) that has been
doing weird things lately -- it often thinks both 800K and 1.4 MB disks are
locked, when the latch is really NOT in that position.  I can put the same
floppy in my Mac's disk drive and it doesn't show up as being locked, so I
don't think it's a crummy out-of-spec disk.

How do these drives work?  Do they have an optical sensor that shines light
through the hole, if the latch is open?  Is there a possibility a lot of dust
is covering up the lens or the sensor is going bad?  Is it really true the
whole disk drive has to be replaced?  The Milpitas Apple dealer said the floppy
disk controller chip is going bad and has to be replaced.  I find it hard to
believe a chip is flaky one day, and works fine for several days afterwards.  I
thought chips die in the first 24-hr. burn-in if they're bad, otherwise last
forever.

If no one around here can help, then I'll ask another Apple dealer for a second
opinion.
            Thanks in advance!       Andrea