The next tape of a multivolume file can be premounted on any physically compatible tape device unless a tape device was reserved via the command SECURE-RESOURCE-ALLOCATION UNIT=mn. In this case, the next tape must be processed on the same device as the preceding tape.
If DMS detects, as the result of a FILE macro, ADD-FILE-LINK command, or from the catalog entry for the file, that the file is stored on several tapes, it first processes the labels of the current tape and then informs the operator that the next tape in the sequence can be mounted.
If a tape change is necessary because the file is continued on the next tape or because the file was not found on the current tape of an MF/MV set, the current tape is rewound and unloaded. If the next tape is already mounted on another device, it is processed by DMS without operator intervention. This is also true for the first tape of a file if this tape was premounted.
If the next required tape is not already mounted, the operator receives a MOUNT message. The system suggests that the tape be mounted on the same device as the preceding tape. If this next tape is mounted on another device and this device is assigned, device management accepts this. In this case, the currently reserved device is released.