IMS catalog data sets

The data sets for the IMS catalog can be created automatically by the IMS Catalog Populate utility (DFS3PU00).

Optionally, you can create the database data sets for the IMS catalog yourself.

The IMS catalog database comprises the following data sets:
  • In each partition, the data sets for the IMS catalog database, DFSCD000:
    • Primary index data set
    • Indirect list data set (ILDS)
    • Four data set groups for the segments of the IMS catalog records (A - D)
  • The data set for the secondary index database, DFSCX000
If the IMS management of application control blocks (ACBs) is enabled, the following system-managed data sets are also associated with the IMS catalog:
  • One or more IMS directory data sets
  • A bootstrap data set
  • A staging data set

For a managed ACBs environment and when the ACBSHR= parameter is set to Y (ACBSHR=Y), all data sharing IMSs use the same set of IMS catalog data sets, IMS directory data sets, a bootstrap data set, and a staging data set. If a data sharing IMS has an FDBR region, the FDBR region shares the same set of catalog-related data sets as its active IMS.

For a managed ACBs environment and when the ACBSHR= parameter is set to N (ACBSHR=N), each data sharing IMS uses its own set of IMS catalog data sets, IMS directory data sets, a bootstrap data set, and a staging data set. If a data sharing IMS has an FDBR region, the FDBR region shares the same set of catalog-related data sets as its active IMS.

In addition, for IMS managed ACBs and ACBSHR=N, each sharing IMS must have a different ALIAS defined in the SECTION_CATALOG of DFSDFxxx PROCLIB. The different ALIAS for each sharing IMS is used to create its unique set of IMS catalog data sets, catalog directory data sets, a bootstrap data set, and a staging data set. If a sharing IMS has an FDBR region, the same IMS catalog and its catalog-related data sets are shared between the active IMS and the FDBR region that are using the same ALIAS.

The DFS3PU00 utility automatically creates any IMS catalog data sets that do not exist.

The system-managed data sets can also be created manually.

The DFS3PU00 utility calculates the size of the database data sets based on both the size of the ACB library and the expansion percentages that you can specify in the DFSDFxxx PROCLIB member.

The DFSDFxxx PROCLIB member is also where you specify the volume serial number for the VSAM key-sequenced data sets or the SMS storage class, data class, and management class for all data sets.

As a HALDB PHIDAM database, the IMS catalog can have one or more partitions. Each partition contains a primary index data set, an ILDS, and four data set groups.