OS/400 data management considerations - IBM - AS/400

CICS/400 uses the native OS/400 file and commitment control facilities to ensure the integrity of data files. Native OS/400 file objects are opened by CICS user shells. CICS shells can share these resources and use native system services to maintain data integrity.

CICS uses the following files types:

  • User database files accessed by CICS application programs. Any number of user files, emulating VSAM access methods for key-sequenced data sets (KSDS), entry-sequenced data sets (ESDS), and relative-record data sets (RRDS), can be attached.
  • A file for each control region that contains all recoverable transient data intrapartition and auxiliary temporary storage data queues.
  • A file for each control region that contains all nonrecoverable transient data intrapartition and auxiliary temporary storage data queues.
  • CICS user journal files (one OS/400 file for each journal).
  • User printer spool files.
  • Display files (for terminal input).
  • Intersystem communications files (ICF).
  • Extrapartition transient data queue files.

All the above CICS resources must be defined to CICS in the appropriate CICS resource definition table. Additionally, the system administrator has to create some of the corresponding file objects before their use within a CICS application.

Notes:

  1. CICS/400 does not support DDM files.
  2. OS/400 file expiration dates have no effect when the files are used under CICS/400.

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