Using the IMS generation utilities to design IMS databases

You can implement your database designs in IMS by coding macro instructions as input to the Database Description (DBD) Generation utility and the Program Specification Block (PSB) Generation utility.

Using the macro instructions, you describe the characteristics of each database and each application program to IMS. By reading the macro instructions, the utilities create DBD and PSB control blocks that are used by IMS and the ACB Maintenance utility. The ACB Maintenance utility generates the application control blocks (ACBs) that are used by IMS during runtime.

In IMS systems that use ACB libraries, the use of macro instructions and the generation utilities is required. In IMS systems that manage ACBs for you, the use of macro instructions and the generation utilities is optional.

If you use macro instructions to implement database designs in IMS systems that manage ACBs, you must populate the IMS catalog before the DBDs, PSBs, and ACBs can be used by IMS, because IMS does not use the DBD, PSB, and ACB libraries that are created by the generation utilities.