The storage key for CSM buffers is key 6, fetch protected. Users set up and access data that resides in CSM buffers. These buffers are obtained from buffer pools that are identified by their buffer size and storage type as listed in Table 1.

Data space storage is a common area data space and is associated with the master scheduler address space. This association results in a data space that persists for the life of the system.

When an application obtains buffers from CSM, that application is considered the owner of those buffers. Based on application specifications, CSM associates buffer responsibility with an address space or a task within an address space. Applications using CSM have the responsibility of returning owned buffers so that storage is available for other users.

Ownership can be transferred to another user. When this occurs, the new owner is responsible for the return of the buffers. CSM manages buffer reclamation during termination at the task or address space level based on ownership. For detailed information about buffer reclamation during termination, see CSM recovery for normal and abnormal termination.

For more information about buffer ownership, see Ownership of buffers.