Returning empty tapes to the scratch pool

If DFSMShsm considers tapes to be empty, they can be returned to the scratch pool in a number of ways, depending on the function that generated the data on the tape. Table 1 summarizes the various ways empty tapes are returned to the scratch pool.

Table 1. How Different Functions Return Empty Tapes to the Scratch Pool
Function	Recycle Method
Backup/Migration	Backup and migration tapes are returned to scratch status as a result of being recycled with the RECYCLE command. Even if they contain no valid data, migration and backup tapes must be recycled to verify that residual data is invalid. Alternate tapes are returned along with their originals.
Dump	Dump tapes can be returned to scratch status as soon as they expire during automatic dump processing. An empty dump tape is managed according to the specifications in the dump class associated with that tape.
Control data set backup	Control data set backup tapes are returned to the scratch pool when their resident backup-version data sets roll off.
ABARS	ABARS tapes are returned to the scratch pool when their resident backup-version data sets roll off or expire.

For any of the functions in Table 1, DFSMShsm invokes the EDGTVEXT exit to communicate the status of empty tapes to DFSMSrmm, and it only invokes the tape volume exit (ARCTVEXT) if SETSYS EXITON(TV) has been specified. For more information about DFSMShsm installation exits, refer to z/OS DFSMS Installation Exits.