>Lets say I upgrade from the B1A model to the E1A model giving me the
>possibility of doubling the available capacity of the tape drives, do I
>need to remove and redefine the drives to TSM?

The topic of 3590 drive upgrading has been exhaustively covered in the past
(see the List archives) and is covered in at least earlier server README
files (as in ftp://ftp.software.ibm.com/storage/tivoli-storage-management/
 maintenance/server/v3r7/AIX/3.7.2.0/README.SRV.3720.txt)  It involves
redefining drives and marking at least Filling tapes read-only.
There are no gotchas - just an enjoyable improvement.

  Richard Sims, BU