Fujitsu MAS3735 Computer Drive User Manual


 
3.1 Control/Sense Commands
C141-E167 3 -
41
3.1.13 RELEASE (17)
Bit
Byte
76543210
0 X‘17’
1 LUN 3rd Pty 3rd Pty Dev ID 0
2
××××××××
3 00000000
4 00000000
5 0000000Link
This command releases the reserve state of an IDD in relation to the INIT that issued this command.
When a reserve state in relation to the INIT that issues this command, or an IDD in the type of
reserve state which is the release object specified in the CDB of this command does not exist, or
even when the IDD is reserved by another SCSI device, this command is terminated normally with a
GOOD status, but it is no influence on the IDD's reserve state.
The INIT that issues this command must notify its own SCSI ID when the SELECTION phase is executed.
When the INIT's ID cannot be specified, this command is terminated with a CHECK CONDITION status
(ILLEGAL REQUEST [=5] / Initiator's SCSI ID not identified [=90-00]) without this command being
executed. Also, the value specified in CDB byte 2 has no meaning and is disregarded, but it is desirable for
X '00' to be specified by the INIT in this byte.
(1) Release function
This command releases a reserve state if a reserve state exists, and if the INIT which issued this
command has a reserve right for the entire IDD (logical unit). See Reserve Right and Third Party
Reserve Function in RESERVE command (Section 3.1.11) concerning the definition of "Reserve
Right."
(2) Release object and third party release function
When the "3rd Pty" bit in CDB byte 1 is "0," this command cancels a reserve state if it exists in the
IDD that has been reserved by a RESERVE command without the INIT that issued this command
specifying the third party reserve function.
When the "3rd Pty" bit is "1," the third party release function is specified and this command can release a
reserve state established in the past by the third party reserve function. When the third party release
function is specified, this command releases the reserve state only when the INIT that issued this command
is the same as the INIT that used the RESERVE command in the past to specify the third party reserve
function which caused the IDD to be reserved for the SCSI device (third party device) specified in the "3rd
Pty Dev ID" field in CDB byte 1 of this command.
Since only 3 bits are defined in the "3rd Pty Dev ID" in this command, the third party release
function is valid only for SCSI devices with SCSI IDs 7 to 0.