Question: Hardware differences between Unidisk 3.5 and 3.5Drive?

[mirageeso@aol.com (MirageESO)]

I have a dying Unidisk 3.5 drive.  It reads ok (I think) but writes junk.  I
understand that there are two different 3.5 drives for the //e.  If true, what
are the differences between them? Can both use the same I/O card? Also, where
could I find detailed information (possibly including Apple part numbers) on
hardware that is compatable with the //e?  Uh.... Also, is there a place I can
buy (or download) manuals for some of this hardware?

Thanks in advance!

John in Stillwater (Now trying to convert my A2 software library to disk
images)