Tape boxed due to lost assign
If tape CHPIDs, control unit, switches, or ESCON connections are incorrectly handled, a tape ASSIGN may be reset (lost). When this occurs on the last path to the tape drive, the MVS™ system will box the device.
If an ASSIGN lost condition occurs while a tape was loaded, the MVS system
may not be able to unload the tape. If this happens, as indicated
by the cartridge remaining in the drive after the job has completed,
perform the following actions at the tape unit:
- Place the READY/NOT READY switch to the NOT READY position.
- Toggle the UNLOAD switch, and the tape should unload.