Nonstandard volume label verification and editor routines

If you specify that an input or output tape has a nonstandard label, the operating system checks for the nonstandard volume label at the beginning of the tape.

Because of conflicting label types or conflicting tape characteristics, various error conditions can occur during the verification of the first record. Under some error conditions, the tape is accepted for use. Under other error conditions, the tape is not accepted and the system issues another mount message. For certain other error conditions, the system gives control to a label anomaly installation exit and possibly to a volume label editor routine. Your installation can use IBM-supplied routines, or it can supply its own routines.

The IBM-supplied volume label editor routines determine the discrepancies between the requested tape and the mounted tape and, if necessary, pass control to the appropriate system routine to create or destroy labels. DFSMSrmm uses a label anomaly exit that prevents the creation and destruction of standard labels. Installation-supplied routines can perform other functions.

If your installation supplies its own volume label editor routines, the first (or only) module of each routine must be named as follows:

OMODVOL1 (for the editor routine associated with open)
EMODVOL1 (for the editor routine associated with EOV)

If either of your installation's editor routines consists of more than one load module, the names for the additional modules must begin with the prefix OMODVOL for the open routine or EMODVOL for the EOV routine. Transfer between the modules must be by name.

For detailed information about these and other available exit routines, see z/OS DFSMS Installation Exits.