All programs can create, use, and delete SCOPE=SINGLE data spaces. Your program would use data spaces in much the same way as it uses private storage in an address space.
Supervisor state or PSW key 0 - 7 programs can create, use, and delete data spaces that they can share with other programs. These data spaces have uses similar to MVS™ common storage.
To protect data in data spaces, the system places certain restrictions on problem state programs with PSW key 8 - F. The problem state programs with PSW key 8 - F can use SCOPE=ALL and SCOPE=COMMON data spaces, but they cannot create or delete them. They use them only under the control of supervisor state or PSW key 0 - 7 programs. This chapter assumes that the data spaces your program creates, uses, and deletes are SCOPE=SINGLE data spaces.
The following figure summarizes the rules for problem state programs with PSW key 8 - F:
| Function | Rules |
|---|---|
| CREATE | Can create SCOPE=SINGLE data spaces. |
| DELETE | Can delete the data spaces it creates or owns, provided the PSW key of the program matches the storage key of the data space. |
| RELEASE | Can release storage in the data spaces it creates or owns, provided the PSW key of the program matches the storage key of the data space. |
| EXTEND | Can extend the current size of the data spaces it owns. |
| Add entries to the DU-AL | Can add entries to its DU-AL for the data spaces it created or owns. |
| Add entries to the PASN-AL | Can add entries to the PASN-AL for the data spaces it created or owns, providing an entry is not already on the PASN-AL as a result of an ALESERV ADD by a problem state program with PSW key 8 - F. If the ALET is already on the PASN-AL, the system does not create a duplicate entry, but the program can still access the data space using the ALET that already exists. |
| Access a data space through a DU-AL or PASN-AL | Can access a data space through its DU-AL and PASN-AL. The entry for a SCOPE=ALL or SCOPE=COMMON data space accessed through the PASN-AL must have been added to the PASN-AL by a program in supervisor state or PSW key 0 - 7. This program would have passed an ALET to the problem state PSW key 8 - F program. |
| LOAD | Can page areas into central storage from a data space created by any other task in that address space. |
| OUT | Can page areas out of central storage to a data space created by any other task in that address space. |
There are other things that programs can do with data spaces. To do them, however, your program must be supervisor state or have a PSW key 0 - 7. For information on how these programs can use data spaces, see z/OS MVS Programming: Extended Addressability Guide.