The company’s technical staff was able to code ACS routines that use these classes, along with the installation’s object-naming conventions, to implement class transitions. During every storage management cycle, OSMC checks each object that is scheduled for storage management processing to see if it is due for expiration. If it is, OSMC deletes it; otherwise, the management class assignment is used to determine if class transition is needed. For class transition, the ACS routines are invoked.

The general logic of the storage management cycle and the ACS routines is as follows (for objects created on day X):

1. For definitions of collections:
   • If the collection name is detail and the object name is Null, then SC=FASTPERF and MC=TRAN7.
   • If the collection name is summary and the object name is Null, then SC=FASTPERF and MC=EXP30.

   These default values are stored in collection name entry in the catalog when the first object is stored to that collection. When neither storage class nor management class is specified on a request to store an object into one of these collections, the object is assigned the default classes associated with that collection.

2. At X + 7 calendar days, objects in MC=TRAN7 are processed by the storage management cycle. MC=TRAN7 does not specify that these objects should be deleted, so the ACS routines are invoked. If an object’s name begins with D (the naming convention for detail objects) and has SC=FASTPERF, the ACS routines change the class assignments to SC=MEDPERF and MC=TRAN180. This change in storage class can cause the object to be relocated in the object storage hierarchy. For example, the object might move from DASD to optical disk to a tape volume, or any combination therein.
3. At X + 30 calendar days, objects in MC=EXP30 are processed by the storage management cycle. The expiration attributes in the definition for MC=EXP30 specify that objects in this class should be deleted at X + 30 calendar days, so that the objects are deleted by OSMC.
4. At X + 180 calendar days, objects in MC=TRAN180 are processed by the storage management cycle. MC=TRAN180 does not specify that these objects should be deleted, so that the ACS routines are invoked. If an object’s name begins with D (the naming convention for detail objects) and has SC=MEDPERF, the ACS routines change the class assignments to SC=LOWPERF and MC=EXP1825. The change in storage class are recorded in the object directory.

   You can conduct an analysis using DB2, SPUFI, or Query Management Facility (QMF™) to determine which volumes in the configuration presently located within real libraries contain only objects with a storage class intended for the shelf or pseudo library. Those volumes found can be ejected from the library and placed in their assigned shelf location. The DB2 analysis will query the object directory table for each storage group required. Query the storage class table to determine the storage class identifier with which to qualify queries.

5. At X + 1825 calendar days, objects in MC=EXP1825 are processed by the storage management cycle. The expiration attributes in the definition for MC=EXP1825 specify that objects in this class should be deleted at X + 1825 calendar days, so that the objects are deleted by OSMC.