Characteristics of the ARCSAEXT Exit

The ARCSAEXT installation exit receives control once for each data set processed during volume space management or backup. As data sets are migrated and backed up, the VTOC entry for each data set that DFSMShsm processes is copied into a VTOC copy data set. The VTOC copy data set contains selected information from the DASD volume that DFSMShsm is backing up or migrating.

DFSMShsm calls this exit for system- and non-system-managed data sets. A flag in the data set VTOC entry (DS1SMSDS) is passed to the exit, indicating whether the data set is system managed. DFSMShsm provides different parameter lists for system- and non-system-managed data sets.

Note: This exit can be passed list and utility DSCBs, but the DSCBs are not placed in the VTOC copy data set because these data sets are not backed up or migrated. For more information about list and utility data sets, see z/OS DFSMShsm Storage Administration.

The ARCSAEXT exit is not called for any of the following data set VTOC entries:

ICF catalogs
CVOLs
VTOCs
VTOC indexes
VVDSs

For integrated catalogs, the exit is called for backup, but not for space management.

The ARCSAEXT routine must be reentrant.