Standard labels are 80-character records that are recorded in EBCDIC or ASCII. The first four characters are always used to identify the labels.
| Identifier | Description |
|---|---|
| VOL1 | Volume label |
| HDR1 or HDR2 | Data set header labels |
| EOV1 or EOV2 | Data set trailer labels (end-of-volume) |
| EOF1 or EOF2 | Data set trailer labels (end-of-data-set) |
| UHL1 to UHL8 | User header labels |
| UTL1 to UTL8 | User trailer labels |
The format of the label for a direct-access volume is the almost the same as the format of the label group for a tape volume label group. The difference is that a data-set label of the initial DASTO volume label consists of the data set control block (DSCB). The DSCB appears in the volume table of contents (VTOC) and contains the equivalent of the tape data set header and trailer, in addition to control information such as space allocation.
User labels are optional within the standard label groups. The format for user header labels (UHL1-8) and user trailer labels (UTL1-8) consists of a label 80 characters in length recorded in either:
The first 3 bytes consist of the characters that identify the label as either:
The next byte contains the relative position of this label within a set of labels of the same type; one to eight labels are permitted. The remaining 76 bytes consist of user-specified information.
Standard user labels are not supported for QSAM striped data sets.
related concepts
Labels for QSAM files