CICS® provides a variety of facilities to store data in and between transactions. Each one differs according to how available it leaves data to other programs in a transaction and to other transactions; in the way it is implemented; and in its overhead, recovery, and enqueuing characteristics.
Storage facilities that exist for the lifetime of a transaction
include:
- Transaction work area (TWA)
- User storage (by GETMAIN commands issued without the SHARED option)
- COMMAREA
- Program storage
These areas are all main storage facilities whose source
is the dynamic storage areas (DSAs), extended dynamic storage areas
(EDSAs), or above-the-bar dynamic storage areas (GDSAs). None of them
is recoverable, and none can be protected by resource security keys.
They differ in accessibility and duration, so each storage facility
meets a different set of storage needs.
