DFSMSdfp provides two address spaces for processing PDSEs: SMSPDSE and SMSPDSE1. A z/OS system can have only the SMSPDSE address space, or both the SMSPDSE and SMSPDSE1 address spaces. Some control blocks that are associated with reading, writing, and loading PDSE members are still located in the extended common service area (ECSA).

SMSPDSE

A non-restartable address space for PDSE data sets that are in the LNKLST concatenation. (The linklist and other system functions use global connections.) The SMSPDSE address space cannot be restarted because global connections cannot handle the interruption and reconnection that are part of an address space restart operation. SMSPDSE is the only PDSE address space for the z/OS system when one of the following conditions exists:

• The IGDSMSxx initialization parameter, PDSESHARING, is set to NORMAL.
• The IGDSMSxx initialization parameters in a sysplex coupled systems environment are set as follows:
  • PDSESHARING(EXTENDED)
  • PDSE_RESTARTABLE_AS(NO)

SMSPDSE1

A restartable address space that provides connections to and processes requests for those PDSEs that are not part of the LNKLST concatenation. To create the SMSPDSE1 address space during IPL in a sysplex coupled systems environment, set the IGDSMSxx initialization parameters as follows:

• PDSESHARING(EXTENDED)
• PDSE_RESTARTABLE_AS(YES)

Related reading:

• For information on analyzing and repairing PDSEs and restarting the SMSPDSE1 address space, see PDSE Diagnostic Aids in z/OS DFSMSdfp Diagnosis.