Private area and extended private area

The portion of the user private area in each virtual address space that is available to the user's application program is referred to as its region. Except for the 16 KB system region area, each storage area in the private area has a counterpart in the extended private area.

The private area contains the following areas:
  • A local system queue area (LSQA)
  • A scheduler work area (SWA)
  • Subpools 229 and 230 (the requestor protect key area)
  • A 16 KB system region area (used by the initiator)
  • A private user region for running programs and storing data.
See the virtual storage map for MVS™ in Figure 1.

The private area user region can be any size up to the size of the entire private area (from the top end of the prefixed storage area (PSA) to the beginning, or bottom end, of the common service area (CSA)) minus the size of LSQA, SWA, subpools 229 and 230, and the system region: for example, 220 KB. It is recommended that the region is 420 KB less to allow for recovery termination management (RTM) processing.

The segment sizes are one megabyte, therefore CSA is rounded up to the nearest megabyte. The private area is in increments of one megabyte.