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SCSI Commands
Quantum DLT 7000 Tape System 5-155
5.19 RESERVE UNIT COMMAND (16h)
The RESERVE UNIT command reserves the specified tape drive for exclusive use
by the requesting initiator or for another specified SCSI device.
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (16h)
1 Logical Unit Number 3rdPty Third Party Device ID Rsv’d
2 - 4 Reserved
5 Unused Reserved Flag Link
Figure 5–74 RESERVE UNIT Command Descriptor Block - Data Format
Table 5–73 RESERVE UNIT Command Data - Field Descriptions
Field Name Description
3rdPty The third party reservation option for RESERVE UNIT allows an initiator to reserve a
logical unit for another SCSI device. This option is intended for systems that use
COPY, and is implemented by the tape drive.
If set to 1, logical unit is reserved for the SCSI device whose ID appears in the Third
Party Device ID field. The tape drive ignores any attempt made by any other
initiator to release the reservation and returns a GOOD status.
If set to 0, no third party reservation is requested and device is reserved for the
initiator that issued the CDB.
Third Party
Device ID
If 3rdPty is set to 1 (indicating that an initiator has reserved the logical unit for
another SCSI device), this field contains the ID number of that SCSI device for
which the reservation was made.