Volume label

The volume label (VOL1) is the first record on an ISO/ANSI labeled tape. It is at least 80 characters long. Although an ISO/ANSI label can exceed a length of 80 bytes, the excess is not within the scope of the standards and will be truncated by the operating system. All Version 3 and Version 4 labels written by the operating system routines will be 80 bytes in length, including those in which an original label greater than 80 bytes is rewritten (as in a density conflict).

The volume label identifies the volume and its owner and is used by the system to verify that the correct volume is mounted. It also protects the volume from unauthorized use.

Volume labels are created by the EDGINERS or IEHINITT utility programs, or by input from the operator during the Open or EOV routine when:

A label type conflict is detected. A label type conflict occurs when the type of label requested differs from the type of label read at load point from the mounted volume.
The first block of a volume cannot be read (except a RACF-protected volume is rejected if failure to read was because the tape format, such as a nonsupported density, was not recognizable by the control unit).

For additional information about the EDGINERS and the IEHINITT utility programs, see the z/OS DFSMSrmm Implementation and Customization Guide and the z/OS DFSMSdfp Utilities.

Volume labels (VOL2 - VOL9) are allowed but not created or processed by the operating system. They are checked only for valid label identification and correct sequencing.

User volume labels (UVL1 - UVL9) are allowed but not created or processed by the operating system. They are checked only for valid label identification and correct sequencing.