When you specify PURGE with the BACKUP parameter, PURGE specifies that DFSMShsm delete all volume information, including the tape table of contents (TTOC) for a tape backup volume. DFSMShsm removes the record of the deleted volume from the BCDS. In addition, DFSMShsm deletes any association with a day in the backup cycle or with a set of spill backup volumes.
If the volume is a tape volume, all valid backup versions that exist on the tape volume are deleted, and the data on the tape is no longer usable. If an error occurs in deleting a valid backup version, DFSMShsm continues deleting all other backup versions but does not delete the backup volume in which the error has occurred.