Old Diskettes

[jacobst <tomjacobsen@bellsouth.net>]

in the 80s I had an Apple II+. with a disk II drive. (Actually still
have it, but it is boxed up).
I wanted to get back into the Apple stuff, so I bought a IIgs on eBay
that came with a duo disk.
After setting up the IIgs, I am finding that most of my old 5.25 disks
(not all) are not readable by the duo disk unit.  the ones that work
seem to work very reliably, but for the ones that don't, I am lucky if
I can get a catalog listing on them once in several tries.  I am not
sure if it is the duo disk not working, or if it is just the floppies
are just too old.

How can I tell if the problem is the duo disk unit, or the floppies
being too old?  What is the life expectancy of the data on the floppy
disks?  Are there any options on getting these old floppies to read so
I can get the data off?

Thanks.