Reference Guide

Chapter 4 SCSI Commands
RESERVE (10) Command (56h)
DLT-S4 Interface Reference Guide 319
Table 176 RESERVE (10)
Command Descriptor Block —
Field Descriptions
If LongID is set to 1 and Extent is set to 0, the Parameter List Length is 8
and the parameter list has the format shown below. The drive preserves
the reservation until one of the following occurs:
• Another valid
RESERVE command from the initiator supersedes it.
• The same initiator releases it.
•A
TARGET RESET message from any initiator releases it.
• A reset condition releases it.
Field Description
3rdPty When set to 1, indicates that the Third Party Device ID field is valid.
LongID When set to 1, the Parameter List Length is 8 and the 8 bytes of the parameter list
carry the device ID of the third-party device. The drive ignores the contents of the
Third Party Device ID in the CDB (byte 3). This bit is ignored if the 3rdPty bit is
not set.
Extent Must be set to 0.
Reservation
Identification
Ignored.
Third Party Device
ID
Required and used only when the 3rdPty bit is set to 1, in which case this field
specifies the SCSI ID of the initiator to be granted the reservation of the drive.
The drive ignores any attempt to release the reservation made by any other
initiator. For example, if ID7 sends ID2 a third-party reservation on behalf of ID6
(the target at ID2 gets reserved for the initiator ID6), only ID7 can release the
target at ID2 (using a third-party release). ID6 cannot release the reservation even
though the reservation was made on its behalf.
Parameter List
Length
The contents of this field specify the length, in bytes, of the parameter list
transferred from the initiator to the drive. This field is ignored and no parameter
data is transferred unless the 3rdPty bit and LongID bits are both set.