...
> Case: q libvol gives list of volumes in library. some of them can be used
> for backup but some of them no. ...

The simple cause could be that the tapes were not internally labeled,
which would be done via Label Libvolume or dsmlabel operation outside of TSM.
(If you get "pre-labeled" tapes from a vendor, you can assume that they are
okay to use right out of the box...but you know what can happen when you
assume.)

   Richard Sims