Switching tape drives in the case of a device error

If a tape was requested via its VSN, a device was requested via its device type, or both were requested implicitly by means of the file to be processed, the operator can move the tape to another device of the same type in the event of a device error.

If a device was reserved explicitly via its mnemonic device name (UNIT operand in the SECURE-RESOURCE-ALLOCATION command), the volume mounted on this device cannot be moved to another device.

In the case of a hardware fault, this means that tape processing is terminated abnormally if the device was reserved explicitly (with UNIT). The operator rejects the PREMOUNT message and the tape is implicitly canceled. This CANCEL state can be cleared only by releasing the tape reservation.