VERify - Verifying Code Through the JES2 Patching Facility
The VERify initialization statement is one of several statements used by
the JES2 patching facility. For the other statements, see REP - Replacing Code Through the JES2 Patching Facility and NAME - Naming the Module to Change Through the JES2 Patching Facility. The JES2 patching facility
allows you to verify data (patches) for the following:
- Any module in JES2 (for example, HASJES20 or an installation exit load module)
- Any absolute storage address from the address space where JES2 is loaded.
- On a hot start, any address in a data space created by JES2 (that is, owned by JES2AUX)
- On any warm start, any address in the JES2 checkpoint data set.
Note: You can verify data patches for HASCxxxx modules if they do
not reside in read-only storage (PLPA).
The JES2 patching facility applies temporary patches to the in-storage
copy of JES2 modules. You place patching facility statements in the JES2
initialization stream; these patches are applied when you initialize JES2.
Because some of the initialization code has already been executed before
the patch facility initialization statements are processed, patches made to
those portions of the code are ineffective; those portions of code do not execute again until you restart JES2. Most patches are applied
immediately as the statements are processed. However, checkpoint updates
are deferred until the checkpoint record is read. Non-checkpoint patches
are not saved across a warm start. JES2 reloads the load modules at different
stages in processing:
- Subsystem support modules are reloaded during all starts except a hot start.
- HASPJES20 is reloaded in response to a JES2 START command any time the subsystem is started.
In addition, you should be aware that the JES2 patching facility does not support:
- Patching a module or data area residing in read-only storage. For example, you cannot use the facility to modify modules in PLPA or PSA.
- Patching a HASPFSSM load module that has been loaded into a functional subsystem address space. Use AMASPZAP (the service aid program that modifies both instructions and data) must be used to patch the HASPFSSM load module.
- Altering the JES2 dump formatting exit modules (HASMxxxx).
- Using a patch across a restart of JES2. Because these patches are valid only until a load module is reloaded, they must be reapplied every time JES2 is started.
The JES2 patching facility statements in the JES2 initialization data set can be specified in either the JES2 patching format or in the AMASPZAP format. All patches in the JES2 patching form should precede any AMASPZAP patches. If you supply the NAME statement or first format type of the AMASPZAP patch, JES2 resets prior verification errors. If a VERify statement fails, following REP statements are rejected until the next NAME statement is reached. For more information on AMASPZAP patches, see "SPZAP" in z/OS MVS Diagnosis: Tools and Service Aids.