Modifying ACB library members online

In IMS systems that use an ACB library, you can add or change individual members of the ACB library and bring these members online while IMS is running by using the ACB library member online change function.

Note: When the IMS management of ACBs is enabled, the member online change function is not supported and the member online change commands are rejected. Instead, IMS activates new and updated ACBs in the online system for you after the associated database (DBD) and program view (PSB) changes are entered in the IMS catalog. If the DBD and PSB changes are submitted by using DDL statements, some of the changes are activated in the online system automatically. Any changes that are not activated automatically are activated by issuing the IMPORT DEFN SOURCE (CATALOG) command.

The ACB library member online change function quiesces only those resources that are affected by the online change, allowing for resources unaffected by the change to remain active concurrently during the online change process.

If any ACB library members that are being modified or deleted by the online change function have been loaded into online storage for use by IMS, IMS removes them from storage at the time of the online change. Non-resident ACB members are reloaded into storage the next time an application program that requires them is scheduled.