Quantum 10K II - Manual (Page 230)

SCSI Description
Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–163
5.30 RELEASE (6) Command (17h)
The RELEASE and the RESERVE commands are used for contention resolution in
multiple-initiator systems. The RELEASE command is used to release a previously
reserved logical unit. The drive will not return an error if the initiator attempts to
release a reservation that is not currently valid.
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (17h)
1 Reserved 3rdPty Third Party Device ID Extent
2 Reservation Identification
3 - 4 Reserved
5 Control
Figure 5–78 RELEASE (6) Command Descriptor Block — Data Format
Table 5–77 RELEASE (6) Command — Field Descriptions
Field Description
3rdPty Third Party Release allows an initiator to release a logical unit that
was previously reserved. If the value in this field is 0, third party
release is not requested.
When the value is 1, the drive releases the specified logical unit, but
only if the reservation was made by the initiator using a third-party
reservation that requested the release for the same SCSI device as
specified in the Third Party Device ID field.
Third Party Device ID Required if the 3rdPty bit is 1. This field specifies the SCSI ID (0
through 7 only) of the initiator whose third party reservation is
being released. (This field must be set if the initiator of the original
third party RESERVE is the source of the RELEASE.)
Extent The drive supports reservations only on entire logical units. The
value must be 0.
Reservation Identification Any value in this field is ignored by the drive.
NOTE: Assuming that the RELEASE Command Descriptor Block is valid, the drive always returns a
GOOD status for this command. An actual release only happens if the initiator has the unit
reserved for itself or a third-party initiator.