Up to eight user header labels (UHL1 to UHL8) may follow the HDR2 label. To make the user header labels available to your program, SUL must be coded on the DD statement and the address of an input user header label routine must be specified in the DCB exit list. If you omit SUL or the user header label entry in the DCB exit list, the system positions the tape past the tape mark immediately after processing the HDR2 label, or the HDR1 label if the HDR2 label is not present. User label processing and the DCB exit list are described in z/OS DFSMS Using Data Sets.