Describing the labels

In the job control statements, you must provide a data definition (DD) statement for each data set to be processed. The LABEL parameter of the DD statement is used to describe the data set's labels. You specify the type of labels by coding one of the following subparameters of the LABEL parameter:

Code: Meaning
SL: IBM standard labels
AL: ISO/ANSI labels
SUL: Both IBM Standard and user header or trailer labels
AUL: Both ISO/ANSI and user header or trailer labels
NSL: Nonstandard labels
NL: No labels
BLP: Bypass label processing
The data set is treated in the same manner as if NL had been specified, except that the system does not check for an existing volume label. If your installation does not allow BLP, the data set is treated exactly as if NL had been specified. Your job can use BLP only if Job Entry Subsystem (JES), RACF, or DFSMSrmm allow it.
LTM: Bypass a leading tape mark, if encountered, on unlabeled tapes.

If you do not specify the label type, the operating system assumes that the data set has IBM standard labels.

RACF protects SL, AL, SUL, and AUL tape volumes. The installation may provide support for RACF protection of NSL tapes. When the first data set on the first volume specified in the DD statement is created, the volume may be automatically defined to RACF if PROTECT=YES is coded in the DD statement. PROTECT=YES may be specified for SL, AL, NL, SUL, AUL, BLP, and NSL tape volumes. For NSL tapes, the first data set on the first volume is not a criterion for a valid PROTECT specification.

The data set sequence subparameter of the LABEL parameter specifies the data set's relative position on the tape. If you do not specify the relative position, the operating system assumes that the data set is first on the reel.

When INOUT, OUTIN, or OUTINX is specified as the processing method in the OPEN macro, the LABEL parameter can override this specification. If INOUT is specified and you want the data set processed for input only, code the subparameter IN in the LABEL parameter. If OUTIN or OUTINX is specified and you want the data set processed for output only, code the subparameter OUT in the LABEL parameter. INOUT is not supported for ISO and ANSI tapes, but is treated as input if the subparameter IN is used in the LABEL parameter.

When new data sets are created, the LABEL parameter is used to record an expiration date and a security protection status in the label. Beginning with RACF 1.7, the LABEL parameter value is also used by RACF to determine the security expiration. If not specified, the expiration date records as zeros, allowing the data set to be overwritten immediately, unless DFSMSrmm is managing the volume. Password protection is not provided.