VOL parameter

A tape volume consists of a tape cartridge or reel. An optical volume consists of a single side of an optical cartridge or a single CD-ROM. Optical cartridges are dual-sided and each side is a separate volume.

The volume identifier is the identifier stored on each tape or optical disk (in the volume label area) that it identifies. An inquiry message is sent to the system operator if a volume identifier is missing or out of order.

Tape volumes must be on the tape units in the same order as their identifiers are specified in the VOL parameter and as the device names are specified in the DEV parameter of the tape device file commands. However, if the tapes are read backward (a function supported in COBOL), the volumes must be in reverse order to that specified in the VOL parameter. Nevertheless, the device names are still specified in forward order in the DEV parameter.

In general, the rule for specifying tape volume identifiers is that as many as 6 characters, containing any combination of letters and digits, can be used. Special characters can be used if the identifier is enclosed in apostrophes. However, if the tape is used on a system other than an iSeries™ system, the requirements for specifying identifiers on that system must be considered.

Optical volume identifiers can be up to 32 characters long and can contain any combination of digits and upper case letters. Each optical volume identifier must be unique. No two optical volumes with the same identifier can be present on the system at the same time.

For labeled tapes, the following rules apply:

• Characters: A maximum of 6 characters, or fewer, can be specified for each volume identifier. Alphabetic and numeric characters can be used in any order.
• Uniqueness: More than one volume can have the same identifier. You may have a file using the same identifier for several volumes; in this case, the system keeps track of the order internally with a sequence number written on the volumes. However, volume identifiers should be unique whenever possible.
• Order: When multiple volumes (with different identifiers) are used in a single operation, they must be in the same order as the volume identifiers specified in the VOL parameter.

Multivolume files

If multiple volumes (tapes) are used in an operation and all have the same volume identifier, that identifier must be specified in the VOL parameter once for each volume used. For example, if three tapes named QGPL are used in a save operation, VOL(QGPL QGPL QGPL) must be specified.

When a multivolume file on tape is processed and multiple tape units are used, the tape volumes must be placed in the tape devices in the same order as they are specified in the VOL parameter. For example, if five volumes and three tape units are used, they are mounted as follows: VOL1 on unit 1, VOL2 on unit 2, VOL3 on unit 3, VOL4 on unit 1, and VOL5 on unit 2.

Values allowed

*MOUNTED

The volume currently placed in the device is used.

*NONE

No volume identifier is specified.

*SAME

Previously specified volume identification does not change.

*SAVVOL

The system, using the save/restore history information, determines which tape volumes contain the most recently saved version. If the device specified in the DEV parameter of the restore command does not match the device of the most recently saved version of the object, an error message is returned to the user, and the function is ended. If the wrong volume is mounted in the unit specified by the command, a message is returned to the system operator that identifies the first volume that must be placed in the device before the restore operation can begin.

volume-identifier

Specify the identifiers of one or more volumes in the order in which they are put on the device and used. Each tape volume identifier contains a maximum of 6 alphanumeric characters. Each optical volume identifier contains a maximum of 32 characters. A blank is used as a separator character when listing multiple identifiers.