Hi,

if you are sure the tape volume is damadged,
then do perform UPDATE VOLUME so that its 
ACCESS is set to DESTROYED.
You may want to use GUI or http client for simplicity.

If you have a backup from this tape (do you regulary perform BACKUP STG ??),
then ADSM will automatically restore this data to another DLT(s) and the
files
will not have to be backuped again.

If you did  not perform BACKUP STG lately,
all files which went destroyed along with this DLT will be re-backuped
with next incremental backup.

And - I strongly recommend you to read the Admin Guide.

bye
Juraj Salak