Standard Labeled Tapes
You define a standard label tape with the DTFMT parameter FILABL=STD. You also must supply a LABELDEF command to specify label description information. This command replaces the VSE TLBL card and is required for standard label processing under CMS/DOS. See LABELDEF Command.
MT1 DTFMT ...FILABL=STD
you
must then supply the following type of LABELDEF command:
labeldef mt1 fid yourfile fseq...
You
can put any description parameters you want on your LABELDEF command
but the filename for it must be MT1 if you coded MT1 as the
label on the DTFMT.After you have set up your DTFMT and LABELDEF, you execute your CMS/DOS program. HDR1 labels are checked or written when an OPEN macro is run. A VOL1 label volume serial number is checked only if the tape is positioned at load point when the label processing begins and if you have specified a VOLID parameter on a LABELDEF statement for the file. Note, if NOREWIND is not specified in the DTFMT macro for the file, the tape is rewound so it is positioned at load point for label processing.
If you want to process user standard labels as well as standard labels in CMS/DOS, you specify FILABL=STD and also supply a LABADDR parameter in the DTFMT for the file. Control is then transferred to your label processing routines after standard labels are processed. The linkage to user standard label routines is exactly the same as in VSE.