Types of Label Processing

If you are running an OS simulation program and using OPEN and CLOSE macros, specify the type of label processing you want in a FILEDEF command for a given file. Detailed information about the FILEDEF command is found in the z/VM: CMS Commands and Utilities Reference. The types of processing you can specify with FILEDEF TAPn command are:
SL
Indicates you are using IBM standard labels.
SUL
Indicates you are using IBM standard user labels.
AL
Indicates that you are using ANSI labels.
AUL
Indicates that you are using ANSI user labels.
NL
Indicates that your tape has no ANSI or IBM standard labels. (A file will not be opened if you specify this for a tape with a VOL1 label.)
BLP
This tells CMS not to process the tape label, however, position the tape at the specified file before processing the data records in the file.
LABOFF
This is the default and indicates that there is no CMS tape label processing for this tape file.
NSL
Indicates you are using a nonstandard label process. You must have already written a routine to process nonstandard labels. The name of this routine must be specified with the NSL option on FILEDEF. An example of the nonstandard label processing is given in Nonstandard Label (NSL) Processing.
Examples of NL, BLP, and LABOFF processing are given in Nonstandard Label (NSL) Processing, Bypass Label (BLP) Processing, and Label Off (LABOFF) Processing.