Selecting the right subpool for your virtual storage request
- Low private
- High private
- Private local system queue area (LSQA) and extended LSQA
- Common system queue area (SQA) and extended SQA
- Common service area (CSA) and extended CSA.
For more information about these virtual storage areas as well as information about virtual storage in general, see the virtual storage overview in z/OS MVS Initialization and Tuning Guide.
- Whether your program is authorized
- How you will use the storage
- What environment your program runs in.
- What is your program's authorization level? (See Program authorization.)
- Do other address spaces need access to the storage or will it be used only by tasks and subtasks in the same address space? (See Selecting private or common storage.)
- Do you want to protect the storage area from unwanted access? (See Selecting fetch protected or non-fetch protected storage.)
- Does your storage area require a particular storage key? (See Selecting the storage key.)
- Is the program accessing the storage running enabled, locked, or disabled? (See Selecting pageable, DREF, or fixed storage.)
- How long will the storage be required? (See Selecting storage persistence.)
- Must the storage area be backed below 16 megabytes or can it be backed anywhere? (See Selecting central storage backing.)
Be sure also to read the discussion of subpools in z/OS MVS Programming: Assembler Services Guide. The information in z/OS MVS Programming: Assembler Services Guide is not repeated in this discussion.
Alternatives to Using Subpool Storage
Data spaces and hiperspaces provide an alternative means of obtaining and sharing storage. For instance, you can use a SCOPE=ALL data space to hold data to be accessed by all programs running in your address space. You can also use a SCOPE=COMMON data space to share data among programs in different address spaces instead of using common storage for that purpose. For more information about creating and using data spaces and hiperspaces, see z/OS MVS Programming: Extended Addressability Guide.