Loading the IMS catalog with the DFS3UACB utility

In IMS systems that use ACB libraries to manage the runtime application control blocks, you can generate ACB members for your databases and application programs and perform an initial load of the IMS catalog with the ACB Generation and Catalog Populate utility (DFS3UACB) by specifying the PSB DFSCPL00 in the utility JCL.

Attention: When the DFSCPL00 PSB is specified in the DFS3UACB utility JCL, the DFS3UACB utility deletes all existing records in the IMS catalog before populating the IMS catalog in load mode.

The DFS3UACB utility generates the ACB library members and loads the IMS catalog in the same job step.

Internally, the DFS3UACB utility calls the ACB Maintenance utility to generate the ACB members. After the ACB generation phase is complete, the DFS3UACB utility calls the IMS Catalog Populate utility (DFS3PU00) to load the IMS catalog.

To generate the ACB members, you specify ACB generation control statements by using the SYSIN DD statement in the utility JCL. For example:

//SYSIN    DD  *
         BUILD PSB=ALL

To load the IMS catalog, you must specify the load PSB for the IMS catalog, DFSCPL00, in the execution parameters that the DFS3UACB utility passes to the DFS3PU00 utility. The execution parameters for the DFS3PU00 utility must be specified by using the DFS3PPRM DD statement in the DFS3UACB JCL. For example:

//DFS3PPRM    DD  *
         DLI,DFS3PU00,DFSCPL00,,,,,,,,,,,Y,N,,,,,,,,,,,,DFSDF=CAT

The utility JCL for the DFS3UACB utility must reference a DFSDFxxx member in the IMS.PROCLIB data set. In the preceding example, the DFS3UACB utility referenced a DFSDFxxx member called DFSDFCAT, as indicated by DFSDF=CAT. The utility references only the catalog section of the DF member, not an IMS specific section.

The execution parameters referenced by the DFS3PPRM DD statement override the default parameters that are used by the DFS3PU00 utility.

Because the DFS3UACB utility calls both the ACB Maintenance utility and the DFS3PU00 utility, all of the restrictions, requirements, prerequisites, and so forth, that apply to these two utilities also apply to the DFS3UACB utility.

Recommendation: Specify a work data set for the DFS3UACB utility to record the ACB members that are generated. Specifying the work data set improves the performance of the populate phase of the job step. The work data set is referenced in the DFS3UACB utility JCL by the ACBCATWK DD statement.