IMS catalog coexistence considerations

If you use the IMS catalog, certain considerations apply when IMS systems of different release levels coexist.

The IMS catalog is release independent. IMS systems at different release levels can use the same IMS catalog. However, because database definitions (DBDs), program views (PSBs), and application control blocks (ACBs) are release specific, the IMS catalog must contain a complete set of release-specific metadata for each release of IMS that uses the IMS catalog.

Consequently, when IMS systems at different release levels share the IMS catalog, the amount of storage that the IMS catalog requires increases by the amount of storage that is required to store the metadata from the ACB libraries of each release that uses the IMS catalog.

You can determine the amount of additional storage that the IMS catalog requires for a new release by providing the ACB library of the new release as input to the IMS Catalog Populate utility (DFS3PU00) and running the utility in analysis mode.

The DBD and PSB metadata for a given release of IMS must be added to the IMS catalog either by DDL or by using the generation and population utilities that are provided with that release.

Earlier versions of IMS cannot process any segments or fields that are added to the IMS catalog DBD by a new release of IMS.