SMS Setup › SMS Definitions › DFSMS ACS Routines

DFSMS ACS Routines

For Dynamic Cache Management, CA Vtape dynamically allocates a cache data set when needed. The dynamic allocation is requested using the data class and storage class defined exclusively for CA Vtape.

If the ACS routines are coded to honor the data class and storage class requested by a user, then no changes are required in the data class or storage class ACS routines. If the ACS routines are set up to automatically override or validate the users' requested data class and storage class, then modifications to these ACS routines will be required.

If a new storage group was defined for CA Vtape, you must update the storage group ACS to assign the new storage group.

If a do-nothing management class was defined for CA Vtape, your management class ACS routine automatically assigns a management class to each allocation or assigns a default, then changes may be required.

The sample ACS routine changes in this section assume that:

• The CA Vtape DSN prefix defined during customization is the default value of CAVTAPE1.
• The data class defined for CA Vtape is DCVTAPE.
• The storage class defined for CA Vtape is SCVTAPE.
• The storage group defined for CA Vtape is SGVTAPE.

The following sample shows a data class ACS change based on the previous assumptions:

IF &DSN = CAVTAPE1.VVE.D*.T*.LIB* OR
   &DSN = CAVTAPE1.VVE.VDATAQ.** OR
   &DSN = CAVTAPE1.VVE.D*.* THEN DO
     SET &DATACLAS = 'DCVTAPE'         
     EXIT CODE(0)
     END 

Note: The data class, DCVTAPE in the sample above, is used by CA Vtape to define its DASD data sets. This data class should not be used in the SMS ACS routines to direct tape mounts to CA Vtape. A separate data class or classes should be defined for intercepting tape mounts. If a DASD data class is used to intercept tape mounts, the tape mounts will be converted by SMS to DASD allocations and the allocations will fail, typically with a SPACE error.

The three data set naming patterns being checked for in the sample are as follows:

• The Tasklib loadlib where the qualifier that starts with a D is following by the date, the qualifier that starts with a T is followed by the time, and the last qualifier is followed by the last digit of the Subsystem number (1-8).
• The data set which backs up a data space communication area, saving the stored information across restarts.
• The work data sets allocated for each Virtual Device where the qualifier that starts with a D is followed by the device number and the last qualifier is the system name. These data sets are 8 MBs in size and one is allocated for each online Virtual Device.

Since all the data set names start with CAVTAPE1.VVE, if you do not need to put these data sets in different storage classes or groups, you could code a single pattern of CAVTAPE1.VVE.** in the data class ACS routine.

The following sample shows a storage class ACS change based on the previous assumptions:

IF &DATACLAS = 'DCVTAPE' THEN DO
     SET &STORCLAS = 'SCVTAPE'         
     EXIT CODE(0)
     END 

The following sample shows a storage group ACS change based on the previous assumptions::

IF &STORCLAS = 'SCVTAPE' THEN DO
     SET &STORGRP = 'SGVTAPE'         
     EXIT CODE(0)
     END 

The following sample shows a management class ACS change based on the previous assumptions::

IF &STORCLAS = 'SCVTAPE' THEN DO
     SET &MGMTCLAS = ''         
     EXIT CODE(0)
     END 

Once these changes are activated in DFSMS, test them by allocating a test data set that matches naming standard of any of these data sets and uses the CA Vtape data class and storage class. After the data set is allocated, execute an IDCAMS LISTCAT to check that the appropriate DFSMS constructs were assigned to the data set and it was allocated on a DASD volume in the correct storage group.