User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Reserve Unit (16h)
256 Quantum DX-Series Software Interface Guide
If, after honoring the reservation, any other initiator attempts to perform
any command except
INQUIRY, REQUEST SENSE, or RELEASE UNIT, the
command is rejected with a
RESERVATION CONFLICT status. That logical
unit ignores a
RELEASE UNIT command issued by another initiator.
An initiator that holds a current reservation may modify that reservation
(for example, to switch third parties) by issuing another
RESERVE UNIT
command to the tape drive.
Medium Changer Considerations for RESERVE UNIT Command
The optional Element Reservation feature defined for Medium Change
devices as described in the ANSI SCSI-2 specification is not supported.
The
RESERVE 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 / RELEASE 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.