Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
196
18.12.2
Parameter data for Read Keys
Table 162 PERSISTENT RESERVE IN, parameter data for Read Keys
Byte
Bit
7 6 5 4 3 2 1 0
0-3
(MSB)
Generation
(LSB)
4-7
(MSB)
Additional length (n-7)
(LSB)
8-15
(MSB)
First reservation key
(LSB)
:
(n-7) - n
(MSB)
Last reservation key
(LSB)
Generation is a counter that increments when PERSISTENT RESERVE OUT command with “Register” or “Preempt
and Clear” completes successfully. Generation is set to 0 as part of the power on reset process and hard reset
process.
The Generation field contains a 32-bit counter that the Target shall increment every time a PERSISTENT
RESERVE OUT command requests a Register, a Clear, a Preempt, or a Preempt and Abort service action. The
counter shall not be incremented by a PERSISTENT RESERVE IN command, by a PERSISTENT RESERVE OUT
command that performs a Reserve or Release service action, or by a PERSISTENT RESERVE OUT command that
is not performed due to an error or reservation conflict. Regardless of the APTPL value the generation value shall be
set to 0 as part of the power on reset process.
The Additional Length field contains a count of the number of bytes in the reservation key list. If the allocation
length specified by the PERSISTENT RESERVE IN command is not sufficient to contain the entire parameter list,
then only the bytes from 0 to the maximum allowed allocation length shall be sent to the Initiator. The incremental
remaining bytes shall be truncated, although the Additional Length field shall still contain the actual number of bytes
in the reservation key list without consideration of any truncation resulting from an insufficient allocation length. This
shall not be considered an error.
The Reservation Key list contains the 8-byte reservation keys for all Initiators that have registered through all ports
with the Target.