Quantum 10K II - Manual (Page 182)

SCSI Description
Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–115
PERSISTENT RESERVATION IN Command (5Eh) (continued)
The figure and table below illustrate and describe the data fields of Read Key data
parameters.
Bit
Byte
7 6 5 4 3 2 1 0
0 - 3
(MSB)
Generation
(LSB)
4 - 7
(MSB)
Additional Length (n – 7)
(LSB)
(Reservation Key List Follows in Bytes 8 – n)
8 - 15
(MSB)
First Reservation Key
(LSB)
n – 7
to
n
(MSB)
Last Reservation Key
(LSB)
Figure 5–51 Read Keys Parameters — Data Format
Table 5–53 Read Keys Parameters — Field Descriptions
Data Field Description
Generation The value in this field is a 32-bit counter in the device server that is
incremented each time a PERSISTENT RESERVATION OUT command
requests a Register, Clear, Pre-empt, or Pre-empt and Clear operation. Note
that PERSISTENT RESERVATION IN commands do not increment the counter,
nor do PERSISTENT RESERVATION OUT commands that perform a Reserve or
Release service action, or by a PERSISTENT RESERVATION OUT command
that is not done due to an error or a reservation conflict. The value in the
Generation field is set to 0 as part of the power on or reset processes.
The value in the Generation field allows the application client that examines
the value to verify that the configuration of the initiators attached to a
logical unit has not been modified by another application client without
any notification of the application client doing the examination.
Additional
Length This field contains the count of the number of bytes that are in the
Reservation Key list (bytes 8 – n). Note that this field contains the number of
bytes in the reservation key list regardless of the value prescribed by the
Allocation Length field in the command’s CDB.
Reservation Keys Each of the Reservation Keys appear as items in a list as bytes 8 through n.
Each entry reflects an 8-byte reservation key registered with the device
server via the PERSISTENT RESERVATION OUT, Reserve, Pre-empt, Pre-empt
and Clear, or Register service actions. Each key can be examined by the
application client for correlation with a set of initiators and SCSI ports