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IMS DBD and PSB Generation Produces a Runtime Library, Not Just Individual ACB Files

Scope: Rocket Enterprise Developer / Enterprise Server 12.0 for Eclipse on UNIX, IMS DBD and PSB generation.

An IMS project build does more than compile COBOL. Enterprise Developer also generates MFS files, DBDs, PSBs, deployment support files, and informational files. The practical deployment insight is that DBD and PSB generation each update a set of runtime artifacts—not merely one compiled control block. Building an IMS Project documents this generation as an integral part of the project build.

Generating a DBD updates:

dbdname.acb
dbdgen2.dat
dbdgen2f.dat

Rocket describes these files as extracted DBD source information formatted into smaller structures optimized for faster runtime access. The .dat files are indexed and can contain multiple generated DBD members. They are written to the project’s IMS > Generated files directory; if that setting is empty, the project directory is used. See DBD Generation.

PSB generation—either through an IDE project build or mfims psbgen—similarly updates:

psbname.acb
psbgen3.dat

Here, psbgen3.dat is an indexed file capable of holding multiple generated PSB members, while the named .acb is the compiled PSB member. Both are created in the configured generated-files directory, as documented in PSB Generation.

This matters at deployment because the Enterprise Server region must be told where the generated library lives. On the region’s IMS Configuration page, ACB File Directory identifies the directory containing the .dat, .idx, and .acb output produced by DBDGEN, PSBGEN, and IMSGEN. That field maps to the ES_ACBLIB environment variable. IMS Configuration separately defines GEN File Directory—mapped to ES_IMSLIB—as the full path to the transaction-definition file. The two paths serve different artifact families and should not be conflated.

A useful build rule follows directly from that split: when a DBD or PSB changes, regenerate it and deploy the resulting member-specific .acb together with the updated shared generation files in the directory referenced by ES_ACBLIB. Pointing the region only at IMS source, or only copying a single .acb while leaving its generated catalogs elsewhere, does not match Rocket’s documented runtime layout.

Takeaway: Treat the IMS generated-files directory as the deployable runtime library: DBD/PSB .acb members and their shared indexed catalogs belong together, and the region must locate them through ACB File Directory (ES_ACBLIB).