DU - Dump Generation

This Natural profile and session parameter determines whether a memory dump is to be generated in the case of an abnormal termination during the Natural session.

Possible settings ON A memory dump is produced in the case of an abnormal termination (TP-monitor dump data set or SYSUDUMP in z/OS batch mode or under TSO). Then the Natural session terminates with the error message NAT9967 or NAT9974.
OFF No memory dump is produced.


  1. In batch mode, subsequent action taken by Natural is determined by the setting of the CC profile parameter.
  2. In online mode, Natural responds with the error message NAT0950, NAT0953, NAT0954, NAT0955 or NAT0956.
  3. For further information on the abnormal termination, you can use the system command DUMP.
SNAP This setting forces an immediate dump in the case of an abnormal termination during a Natural session.

The Natural session continues as with DU=OFF after the dump has been taken.

FORCE This setting forces an immediate dump in the case of an abnormal termination during a Natural session and terminates the Natural session immediately. This is useful for testing purposes in some environments.

If Natural is LE enabled, Natural terminates the Natural session immediately without a dump and passes control to the LE error handling. It is therefore strongly recommended to specify the LE run-time option TERMTHDACT(UAIMM) to get all the required diagnostic information.


This works as with DU=ON, except that the session is terminated with the abend occurred - instead of the error message NAT9974.

DU=ABEND is not available with the Natural session parameter DU.

Default setting OFF
Dynamic specification yes
Specification within session yes Applicable statement: SET GLOBALS
Applicable command: GLOBALS


  1. Within a Natural session, the profile parameter DU can be overridden by the session parameter DU.
  2. Setting the DU profile parameter may impair the system performance considerably, due to I/O processing on the dump data set.
  3. Be careful when you use this parameter, because all programs and subroutines currently active for the current user will be retained in the Natural buffer pool.
  4. DU=ON, DU=SNAP or DU=FORCE may cause buffer fragmentation which may result in a significant degradation in system performance.
  5. Under openUTM, this parameter is ignored; under openUTM, a dump is always produced in the case of an abnormal program termination.
  6. Profile parameter DUE can be used to get a storage dump for specific errors.
  7. Under Natural Security, the setting of this parameter can be overridden by the Session Parameters option of the Library Profile.