SYSABEND, SYSMDUMP, and SYSUDUMP DD statements

Purpose: Use a SYSABEND, SYSMDUMP, or SYSUDUMP DD statement in a job step to direct the system to produce a dump. The system produces the requested dump:

If the step terminates abnormally.
If the step starts to terminate abnormally, but system recovery procedures enable the step to terminate normally.

The dump DD statements for requesting dumps are:

SYSABEND DD statement

Produces a dump of user and system areas; this dump contains all the areas dumped in a SYSUDUMP, plus:

The local system queue area (LSQA), including subpools 229, 230, and 249
The input/output system (IOS) control blocks for the failing task.

The dump is formatted, so that it can be printed directly.

SYSMDUMP DD statement

Produces a dump of the system areas and the program’s address space. The dump is unformatted and machine-readable. It must be processed by the interactive problem control system (IPCS) and therefore should not be directed to SYSOUT. z/OS® R6 introduced system-determined BLKSIZE support for SYSMDUMPs. If you wish to control the BLKSIZE for compatibility with tools developed for earlier releases, add the following DCB attributes to your SYSMDUMP DD statement.

DCB=RECFM=FB,LRECL=4160,BLKSIZE=4160

SYSUDUMP DD statement

Produces a dump of user areas. The dump is formatted, so that it can be printed directly.

The dump contents are as described only when the installation uses the IBM-supplied defaults for the dumps. The contents of these dumps can be set during system initialization and/or can be changed for an individual dump in the ABEND macro instruction, in a CHNGDUMP command, and by a SLIP command. For details, see z/OS MVS Initialization and Tuning Guide.

Dumps are optional; use a dump DD statement only when you want to produce a dump.

References: For information on how to interpret dumps, see z/OS MVS Diagnosis: Tools and Service Aids.