Volume Label Editor Routines

When data sets are written on tape, data management's open or EOV routine might detect these:

Label—Type Conflict. Conflict between the label type specified by the user and the actual label type on the mounted output volume (OUTPUT or OUTIN).
Density Conflict. Conflict between the recording density specified by the user and the actual density of the output volume (OUTPUT, OUTIN, or INOUT) mounted on a dual-density tape unit.
Volume Serial Conflict. Conflict between the volume serial number specified by the user and the actual volume serial number on the mounted output volume (OUTPUT or OUTIN).
Label Version Conflict. Conflict between the existing label version on the mounted output volume and ISO/ANSI Version 3 or Version 4 level that open or EOV want to use either by default or by using the force option in the VOLM (Volume Mount Tape Installation exit) or by the FORCE3 or FORCE4 parameter specified in the ALVERSION keyword of the DEVSUPxx Parmlib member.
Mode Conflict. Conflict between the compaction mode specified by the user and the actual compaction mode of the mounted output volume (OUTPUT or OUTIN).
Track Conflict. Conflict between the cartridge type of the mounted output volume and that of the drive (OUTPUT or OUTIN). The first block of the tape cartridge cannot be read. The system has reconstructed an SL or AL volume label from sense bytes. The first 11 bytes match the volume label. The rest of the 80 bytes are EBCDIC or ASCII blanks according to whether the first four bytes are EBCDIC or ASCII. If the label is in ASCII, OPEN or EOV has translated it to EBCDIC.

If the internal volume serial number does not equal the external (optical) volume serial number, create the internal equal to the external in the volume label editor routines for nonspecific volume requests. When such conflicts occur, control is given to the volume label editor routines. The IBM-supplied editor routines determine whether the data management routines can resolve the conflict.

If the volume label editor routines accept a conflict while opening to the first data set on an ISO/ANSI Version 3 or Version 4 volume, the system enters RACF, checks the expiration date, and enters the file access exit before requesting permission from the operator to create a new VOL1 label (the volume access exit is entered prior to label—type conflict processing).

If a nonspecific volume request is made for a standard labeled tape, but the mounted volume does not have a standard label, data management issues a message to the operator requesting that either the volume serial number and owner information be supplied or, optionally, that the use of this tape volume be refused. If a specific volume request is made and the label format of the mounted volume does not match the format specified in the processing program, data management rejects the tape and issues a message to mount another volume. However, if a specific volume request is made for an SL tape and the mounted tape is unlabeled, data management gives the operator the option of labeling or rejecting the tape.

If a nonspecific volume request is made for a nonstandard labeled or unlabeled tape, but the mounted volume has a standard label, data management gives the operator the option to allow or refuse the use of the tape under the following conditions:

The file sequence number is not greater than 1.
The expiration date passed, or the operator allowed the use of the tape.
The volume is neither password-protected nor RACF-protected, and the accessor is ALTER authorized.

If these conditions are not met, data management rejects the tape and issues a mount message. Data management follows the same procedure if the conditions are met, but the operator refuses the use of the tape.

If the operator accepts the tape, data management destroys the volume label by overlaying it with a tapemark. It deletes the RACF definition of the volume if it was found to be RACF defined and the user is ALTER authorized. Even if the password is known, a password-protected tape that is not RACF defined is not converted to NL or NSL.

For dual-density tapes with standard labels, data management rewrites the labels in the density specified when an output request is made to the first data set on a volume. When an output request is made to other than the first data set, the labels are rewritten in the density specified in the existing labels.

If the existing ISO/ANSI label is not Version 3 or Version 4, during an output request to the first data set on the volume, the volume label editor routines provide an option allowing the label to be rewritten to conform to Version 3 or Version 4 standards. The WTOR message processing installation exit can be used to provide label information for the new Version 3 or Version 4 label instead of requiring the operator to supply it through a WTOR message (see WTO/WTOR Message Processing Facility Installation Exit (IEAVMXIT)). If a version conflict is detected for an output request to other than the first data set, the volume is unconditionally rejected by open/EOV after issuing an IEC512I LBL STD "VRSN" error message.

You can replace the IBM-supplied editor routines with your routines to resolve the conflict. Your editor routines can:

Resolve label and density type conflicts by writing labels, by overwriting labels with a tapemark, and by performing write operations to set the correct density on a dual-density tape device.
Reset the appropriate system control blocks (in effect, change the program specifications) to agree with the label type and/or density of the currently mounted volume.
Provide a combination of these actions, including removing the volume under certain conditions.

There are two IBM-supplied editor routines. One gets control from the open routine for handling the first or only volume of a data set. The other gets control from the EOV routine for handling the second and subsequent volumes of a multivolume data set. You can replace either or both of these routines.