Using the SMS pre-ACS calls to DFSMSrmm, you can use any existing DFSMSrmm and EDG_EXIT100 exit scratch pool and EDG_EXIT100 exit policy assignment decisions as input to your SMS ACS logic to enable you to direct new data set allocations to the correct media. You can use SMS ACS to decide if data sets are to be system-managed or not system-managed. For system-managed data sets, you can decide if they are to be DASD or tape. For system-managed tape data sets, you can decide to which library or library type you would like the allocation directed. This can help you with VTS implementation.

To use DFSMSrmm and EDG_EXIT100 decisions within your ACS processing, use the pre-ACS processing. Implement or customize the sample EDGUX100 exit module to feed pool and VRS management value information into ACS. Base your ACS processing decisions on the MSPOOL and MSPOLICY values that come from DFSMSrmm scratch pool processing and EDG_EXIT100 exit processing. You can plan to move the EDG_EXIT100 exit decisions into your SMS ACS routines to enable the EDG_EXIT100 exit processing to be ignored or removed some time in the future.

DFSMSrmm always attempts to pass values for the MSPOOL and MSPOLICY ACS read-only variables. If you do not use an EDG_EXIT100 exit, the MSPOOL variable is set to the DFSMSrmm system-based scratch pool decision. If you do not use the EDG_EXIT100 exit, there is never a value set for MSPOLICY. DFSMSrmm sets a pre-ACS variable only if the variable has not yet been set using the pre-ACS exit. Since DFSMSrmm gets control after the installation exit, any vendor decisions or any customer decisions take precedence.