Prevent NCT2

Performs data set cleanup before the original job run.

Additional information	Description

Usage	Optional
Format	Select one of the following from the Prevent NCT2 list box: Blank – Do not perform data set cleanup before the original job run. Default. N (No) – Do not perform data set cleanup before the original job run. Y (Yes) – Perform data set cleanup before the original job run. This value is not valid for started tasks. L (List) – Do not perform data set cleanup before the original job run; but generate the messages that would be required for GDG adjustment during restart. F (Flush) – Halt processing of the job if any data set cleanup error is detected (even if z/OS would not have stopped processing the job).
Variable Name	None
Alternate names	Control‑M/EM Utilities: PREVENTNCT2 Control-M Report: PREVENT NCT2 Control‑M/Server Utilities: (none) Control‑M for z/OS: PREVENT‑NCT2 Control‑M/EM API: prevent_nct2
Alternate Formats
Control‑M/EM Utilities	Valid values: 0 - No. Does not prevent data set cleanup. 1 - Yes. Prevents data set cleanup. EXAMPLE: <PREVENTNCT2="1"/>
Control‑M for z/OS	PREVENT‑NCT2 is composed of two parameters:
	PREVENT‑NCT2	Valid values: N - No Y - Yes L - List F - Flush
	DFLT	Protected field indicating the PREVENT-NCT2 default value for the Control‑M for z/OS site. The default is set in parameter NCAT2 in the CTRPARM member in the IOA PARM library. A value specified in the PREVENT-NCT2 parameter overrides the site default.

If a job tries to create a data set that already exists, the job may fail with a DUPLICATE DATA SET ON VOLUME error. If a job tries to create a data set whose name is already cataloged, the job may fail with an error message that indicates a reason of NOT CATLGD for reason code 2 (the Control‑M/Restart term PREVENT-NCT2 is derived from this error situation). These problems can be avoided by performing data set cleanup. During data set cleanup, Control‑M/Restart does the following:

Deletes and uncatalogs the old data sets. This prevents DUPLICATE DATSET ON VOLUME and NOT CATLGD 2 errors.
Performs Generation Dataset (GDG) Adjustment, which is described in the Control-M/Restart User Manual.

Control‑M/Restart automatically performs data set cleanup prior to restarts and reruns. However, it may be desirable to perform data set cleanup before the original job run, because data sets accessed by the job can have file-related errors that were generated by an entirely different job. When data set cleanup is performed as part of the original job request, it is called PREVENT-NCT2 processing. The site-defined default in parameter NCT2 in member CTRPARM determines whether data set cleanup is to be performed before the original job run. The Prevent NCT2 parameter can be used to override this default to determine what data set cleanup instructions are provided to the original job run. Possible values, and their effects, are described below:

When N is specified, no special action is taken by Control‑M/Restart. Data set cleanup is not performed.
When Y is specified, Control‑M/Restart performs data set cleanup before the original job run. It deletes and uncatalogs all data sets that can cause NCT2 and duplicate data set errors during execution, and performs GDG adjustment if necessary.
When L is specified, data set cleanup is not performed for the original run, but messages that would be required for GDG adjustment during restart are generated. Without these messages, GDG adjustment might not be properly performed during restart. In addition to the GDG adjustment messages, the same messages that are generated during simulation of data set cleanup are also generated.
When F is specified, if a file catalog error is detected, processing is halted (even if normal z/OS processing would not handle the problems as a fatal error) and an appropriate error message is generated.
NOTE: If you would normally specify N (that is, Control‑M/Restart processing is not desired for the original run), but the JCL requires GDG processing, BMC Software recommends that you specify value L instead of value N.

If a value of Y, L, or F is specified (that is, if some kind of special NCT2 processing is desired), a ControlR step is automatically added as a first step of the submitted job. The PREVENT NCT2 parameter has no impact on restarts, because Control‑M/Restart automatically performs data set cleanup prior to restarts.

Parent Topic

General parameters