You define pools to DFSMSrmm in parmlib that the EDG_EXIT100 installation exit can select for new tape data sets. The new tape data sets are to be created on nonspecific volumes. During OPEN processing DFSMSrmm uses the pool that you specify to validate that a scratch volume has been mounted from the selected pool. Each pool can be defined with different attributes, and can either be a scratch pool or a rack pool.

You can specify whether you want DFSMSrmm to disable the autoloader when the EDG_EXIT100 installation exit selects a scratch pool. By using the exit module to disable the loader, you can prevent the loader from being emptied when it contains volumes from another pool. If you are using multiple scratch pools and a tape drive is allocated for a request that requires a pool that has not been pre-loaded, DFSMSrmm rejects pre-loaded volumes from other pools.

You can pass the EDG_EXIT100 exit selected scratch pool prefix to your ACS routines for making allocation decisions and for assigning storage group names for system-managed tape data sets. You can do this using the pre-ACS call to the EDG_EXIT100 installation exit. See Using the EDG_EXIT100 installation exit from pre-ACS processing for information about using the EDG_EXIT100 installation exit from pre-ACS processing. You can replace the EDG_EXIT100 processing by using the DFSMSrmm calls to SMS ACS routines requesting a storage group name. Refer to Using SMS tape storage groups for DFSMSrmm scratch pooling for information about DFSMSrmm ACS support for storage group.