Falling back from IMS-managed ACBs after resource updates were activated

If your installation has activated new or modified databases or program views after enabling the IMS management of ACBs, the procedure for falling back to installation-managed ACB libraries (ACBLIBs) includes recreating the DBD, PSB, and ACB libraries from the active resources in the IMS catalog.

The following procedure does not include steps for falling back from an IMS catalog. Disabling the IMS catalog is not required when falling back to installation-managed ACBLIBs.

The following procedure is generally applicable to both falling back within a release and falling back to a prior release of IMS.

Procedure

  1. Build the input statements for DBD Generation and PSB Generation utilities from the IMS catalog by using the DFS3LU00 utility.
  2. Build the DBD and PSB libraries by running the DBD and PSB Generation utilities.
    If you are falling back to a prior release of IMS, be sure to use the utilities for that release of IMS.
  3. Build the ACB library by providing the DBD and PSB libraries as input to the ACB Maintenance utility.
    If you are falling back to a prior release of IMS, be sure to use the utilities for that release of IMS.
  4. In the <CATALOG> section of the DFSDFxxx PROCLIB member, specify ACBMGMT=ACBLIB.
  5. If you use the IMS Catalog Definition exit routine (DFS3CDX0), modify it to indicate that the IMS management of ACBs is not enabled.
  6. If necessary, update any JCL to reference the ACBLIB, DBDLIB, and PSBLIB.
  7. If DBRC was configured to refer to the IMS catalog for database definitions, reconfigure DBRC to refer to the DBDLIB instead by issuing the CHANGE.RECON command with NOCATALG specified.
  8. Restart the IMS system.

Remove the MANAGEDACBS control statement from the JCL for the IMS Catalog Populate utility (DFS3PU00) before running the utility again on a system that uses ACB libraries.

If necessary, revert any tools or products that were updated to run in the IMS-managed ACBs environment so that they use the ACB, DBD, and PSB libraries again.