Creating work areas for the ESAP

After loading the ESAP modules, IMS obtains work area storage for the ESAP if work area definitions are contained in the ESMT.

The IMS DFSEWAL macro is used to generate work area definitions in the ESMT.

The process IMS uses to create the work areas is similar to the process used to load ESAP modules except that IMS can either:

Create the control block for the work area addresses (as it creates the EEVT for the ESAP module addresses), or
Store the work area addresses into the same control block that has the module addresses.

The intended use of the EEVPEWA field in the EEVTP is to hold the address of a control block referred to as the external subsystem work area list (EWAL) that contains the addresses of the work areas created for the ESAP. However, the external subsystem must have provided the appropriate specifications in the ESMT to cause IMS to store the address of the EWAL in this field.

IMS creates each work area either in the control region or in dependent regions or both, according to the definition. Storage is obtained in subpool 251, if specified; otherwise it is obtained in subpool 230.