Storing data in a transaction

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.