The ACB repository

The ACB repository is a VSAM KSDS that contains ACBs as loaded and/or updated from the active ACB library (ACBLIB).

Implementation of the ACB repository improves the performance of IMS Recovery Expert functions that access the ACB libraries of large systems. For example, the creation of application profiles might require the reading of a significant portion of the active ACB library. Use of the ACB repository will substantially reduce response times.

The ACB repository is utilized by running the BSYACBRU utility for a given SSID, which compares the ACB repository to the active ACBLIB. When an ACB member in the repository has a different date+time value from that of its ACBLIB counterpart, the utility will replace the repository member with the ACBLIB member. If a member exists in the ACBLIB but not in the ACB repository, the utility will add it to the ACB repository.

Note: If the supplied SSID is a single-system IMS ID that is part of an IMS Recovery Expert Control File's IMS Group Name, then the IMS Group Name is used.

Each unique KSDS key contains the ACB name, type (DBD or PSB), SSID or Group IMS ID, and sequence number of each ACB's records. An ACB's record contains a date+time value representing when the ACB was last changed in the ACBLIB. This information is used by BSYACBRU for comparison to the ACB repository.

Notes:
  • At this time IMS Recovery Expert does not require PSBs for functions related to the ACB repository. As such, the ACB repository will only contain DBDs.
  • If the IMS system is in the IMS-managed ACBs environment, the ACB repository function is disabled even if the ACB repository is configured.