PATCH subcommand

Use the PATCH subcommand to repair data residing in a RECFM=F or RECFM=FBS data set or to manage the list of patches in effect for a dump.

Patching may impact IPCS performance and is intended to be used very sparingly. The reason that a patching capability has been included is the following scenario:

You attempt to run a high level report against a dump. The report is important for your analysis.
The report writer encounters a block that appears to be damaged. Rather than using the contents of the damaged block and risking the production of a misleading report, the report writer identifies the block and the damage detected.
You examine the damaged block, verify that its damage is not the root problem that you sought, and are able to determine values that repair damage to it.
You use the PATCH subcommand to identify the repairs to IPCS. IPCS does not alter the dump data set in any way. The alterations are stored in your dump directory.
Patching storage that IPCS knows can be seen from multiple perspectives, such as both common virtual storage and real storage visible to each CPU in the dumped system, affects all perspectives.

Restrictions
- IPCS may access dump data before application of a patch, recording conclusions regarding that data in the dump directory before application of a patch. The PATCH subcommand does not attempt to locate and alter any such data. Some of this data may be affected using other subcommands such as
  - DROPDUMP RECORDS(TRANSLATION)
  - DROPMAP
  - DROPSYM
- The current implementation of PATCH support directly uses data in dump records for most information associated with DISPLAY(MACHINE) output and the related data that may be extracted from a dump using the EVALUATE subcommand. Processing of storage by EVALUATE does honor PATCH requests.
- Storage may be added to what was dumped, such as from ASID(75), through PATCH processing, but PATCH will not attempt to identify the absolute or real storage locations where that storage would have resided in the dumped system. If this is important to your analysis, you must use PATCH to add it from all perspectives important to your analysis.
Qualifier
The following qualifiers distinguish the functions performed by the PATCH subcommand:
Qualifier

Function

ADD

Causes the PATCH subcommand to store a new patch. See Adding or replacing a patch for more information. Existing, overlapping patches are considered to be an error and cause the new patch to be rejected.

DELETE

Causes the PATCH subcommand to delete patches. See Deleting patches for more information.

LIST

Causes the PATCH subcommand to list patches. See Listing patches for more information.

REPLACE

Causes the PATCH subcommand to store a patch, replacing one or more existing ones whose descriptions overlap the new one. See Adding or replacing a patch for more information. At least one existing, overlapping patch is expected. If there is none, it is considered to be an error, and the new patch is rejected.

STORE

Causes the PATCH subcommand to store a patch, replacing any existing ones whose descriptions overlap the new one. See Adding or replacing a patch for more information.