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5-110 Maxtor Atlas 10K V
5.29 RELEASE (10) Command (57h)
The RELEASE and the RESERVE commands are used for contention resolution in
multiple-initiator systems. The RELEASE (10) 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. The data format and field
descriptions are shown in Table 5-157 and Table 5-158 respectively.
Table 5-157 RELEASE (10) Command Descriptor Block-Data Format
Table 5-158 RELEASE (10) Command — Field Descriptions
Note: Assuming that the RELEASE Command Descriptor Block is valid, the drive
always returns a GOOD status for this command. An actual release only hap-
pens if the initiator has the unit reserved for itself or a third-party initiator.
Bit
Byte
765 4 3210
0 Operation Code (57h)
1 Reserved 3rdPty Reserved LongID Extent
2 Reservation Identification
3 Third Party Device ID
4 - 6 Reserved
7 - 8
(MSB)
Parameter List Length
(LSB)
9 Control
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. If 3rdPty = 1, then the device server will
release the specified logical unit, but only if the initiator ID, 3rdPty bit, and third party device ID
are identical when compared to the RESERVE command that established the reservation.
LongID
If the Long ID bit is set to 1, the Parameter List Length is 8 and the eight bytes of the parameter
list carry the device ID of the third party device; the contents of the Third Party Device ID in the
CDB (byte 3) are ignored.
Third Party De-
vice ID
If the Third Party Device ID value that is connected with the reservation release is smaller than
255, the LongID bit may be 0 and the ID value sent in the CDB. If LongID bit = 0, the Parameter
List Length field also = 0. If the Third Party Device ID value is greater than 255, LongID = 1.
Device servers that support device IDs greater than 255 will accept commands with LongID = 1;
device servers that do not support IDs greater than 255 may reject commands with LongID set =
1. Device ID formats are protocol-specific.
Parameter List
Length
The contents of this field specify the length, in bytes, of the parameter list that will be transferred
from the initiator to the target.
Extent The drive supports reservations only on entire logical units. The value must be 0.
Reservation Iden-
tification
Any value in this field is ignored by the drive.