Compatibility with DBT V1 HSSR

IMS High Performance Unload is compatible with IMS System Utilities/Data Base Tools Version 1, High Speed Sequential Retrieval (program number 5668-856, also referred to as DBT V1 HSSR), with certain exceptions.

IMS High Performance Unload supports compatibility with DBT V1 HSSR in the following ways:

  • JCL can be used without modification.
  • Input control statements can be used without modification except that the following input control statements might need minor modifications if the same results of the DBT V1 HSSR are required:
    • DIAGG control statement in the HSSROPT data set
    • Position 22 of the DBD control statement in the FABHFSU CARDIN data set
      Note: For complete explanations on these specifications, see the following topics:
  • An application program that uses a DBT V1 HSSR call can be used without reassembling or re-link-editing.
  • A user exit routine of DBT V1 HSSR needs the following modification to be run under IMS High Performance Unload:
    • A user exit routine must be reassembled or re-link-edited or both in the same IMS system environment under which the routine is used, if the IMS macros that depend on the IMS release levels are used in the routine.
    • A user exit routine that refers to the HDMBOKEY field of the HDMB control block must be modified from a 3-byte-long field to a 4-byte-long field.
    • A user exit routine can be run either in AMODE=24 or AMODE=31, but a user exit must be link-edited with AMODE=31. See the following topics for the requirements for exit routines:

Other differences are the same as those for DBT V2 HSSR. See Compatibility with DBT V2 HSSR.