User's Guide

Chapter 2 Media Changer Commands
Persistent Reserve In Command (5Eh)
Quantum SuperLoader 3 Software Interface Guide 72
Table 34 Read Keys
Parameters
The following figure and table illustrate and describe the data fields of
Read Reservations data parameters.
n – 7
to
n
(MSB)
Last Reservation Key
(LSB)
Field Name Description
Generation The value in this field is a 32-bit counter in the device server that is
incremented each time a
PERSISTENT RESERVE OUT command requests a
Register, Clear, Pre-empt, or Pre-empt and Clear operation. Note that
PERSISTENT RESERVE IN commands do not increment the counter, nor do
PERSISTENT RESERVE OUT commands that perform a Reserve or Release
service action, or by a PERSISTENT RESERVE 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 RESERVE OUT, Register or Register and Ignore Existing
Key
service actions. Each key can be examined by the application client for
correlation with a set of initiators and SCSI ports.
Bit
Byte76543210