CSM includes an application programming interface (API) that allows users to obtain and return CSM buffers, change ownership of buffers, copy buffers, and perform other functions related to CSM buffer arrangement. Applications must be authorized to use CSM. The storage key for CSM buffers is key 6, fetch protected. Users set up access data that resides in the CSM buffers. These buffers are obtained from buffer pools that are identified by their buffer size and storage type as follows:
Storage Types |
Buffer Sizes (in KB) |
||||
Data space |
4 |
16 |
32 |
60 |
180 |
ECSA |
4 |
16 |
32 |
60 |
180 |
Data space storage is a common area data space. It is associated with the master scheduler address space, which results in a data space that persists for the life of the system. When an application obtains buffers from CSM, it is considered the owner of those buffers. CSM can associate buffer responsibility with an address space or a task within an address space, based on application specifications. Applications using CSM are responsible for returning owned buffers so that they are available for others. If ownership is transferred to another user, the new owner is responsible for the return of the buffers. CSM manages buffer reclamation during termination at the task/address space level based on ownership.
See also: