Quantum DLT 8000 Product Manual page 347

SCSI Commands
RESERVE UNIT (6) Command (16h) (continued)
An initiator that holds a current reservation may modify that reservation (for example,
to switch third parties) by issuing another RESERVE UNIT (6) command to the tape
drive.
Medium Changer Considerations for RESERVE UNIT (6) Command
The optional Element Reservation feature defined for Medium Change devices as
described in the ANSI SCSI-2 specification is not supported. The RESERVE UNIT
command is defined the same as for the tape drive. The whole loader unit may be
reserved. This is separate from a reservation of the tape drive.
The RESERVE UNIT/ RELEASE UNIT commands operate on a LUN basis. The Medium
Changer and the tape drive are generally handled as different devices. In the case of a
reserved drive LUN, a MOVE MEDIUM command issued to the Medium Changer LUN
cannot insert or remove a tape cartridge to or from a tape drive unless the tape drive is
reserved by the same initiator.
Quantum DLT 8000 Tape System 5-203