The storage protection global option

You can control whether your CICS® region uses storage protection by specifying the STGPROT system initialization parameter. By default, CICS uses storage protection.

When you specify STGPROT=YES, or allow the system initialization parameter to default, the storage for the CICS dynamic storage areas for user applications is allocated from user-key storage. These DSAs are the UDSA, SDSA, EUDSA, ESDSA, GUDSA, and GSDSA. If you specify STGPROT=NO, the storage for these DSAs is allocated from CICS-key storage.

Running a CICS region without storage protection (STGPROT=NO) is suitable for pure terminal-owning regions (TORs) that do not execute user transactions.