Maxtor 10K V manual Release 10 Command 57h, 157RELEASE 10 Command Descriptor Block-Data Format

5.29RELEASE (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 5-157RELEASE (10) Command Descriptor Block-Data Format

Bit	7	6	5	4		3	2	1	0
Byte
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

	Table 5-158RELEASE (10) Command — Field Descriptions
Field	Description
	Third Party Release allows an initiator to release a logical unit that was previously reserved. If the
3rdPty	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.
	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
Third Party De-	List Length field also = 0. If the Third Party Device ID value is greater than 255, LongID = 1.
vice ID	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	The contents of this field specify the length, in bytes, of the parameter list that will be transferred
Length	from the initiator to the target.
Extent	The drive supports reservations only on entire logical units. The value must be 0.
Reservation Iden-	Any value in this field is ignored by the drive.
tification

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.

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