User Manual

SCSI Commands Reference Manual, Rev. J 126
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
3.14 PERSISTENT RESERVE OUT command
3.14.1 PERSISTENT RESERVE OUT command introduction
The PERSISTENT RESERVE OUT command (see table 88) is used to request service actions that reserve a logical unit for the
exclusive or shared use of a particular I_T nexus. The command uses other service actions to manage and remove such persistent
reservations.
I_T nexuses performing PERSISTENT RESERVE OUT service actions are identified by a registered reservation key provided by the
application client. An application client may use the PERSISTENT RESERVE IN command to obtain the reservation key, if any, for
the I_T nexus holding a persistent reservation and may use the PERSISTENT RESERVE OUT command to preempt that persistent
reservation.
If a PERSISTENT RESERVE OUT command is attempted, but there are insufficient device server resources to complete the
operation, the command shall be terminated with CHECK CONDITION status, with the sense key set to ILLEGAL REQUEST, and
the additional sense code set to INSUFFICIENT REGISTRATION RESOURCES.
The PERSISTENT RESERVE OUT command contains fields that specify a persistent reservation service action, the intended scope
of the persistent reservation, and the restrictions caused by the persistent reservation. The TYPE and SCOPE fields are defined in
3.13.3.4 and 3.13.3.3. If a SCOPE field specifies a scope that is not implemented, the command shall be terminated with CHECK
CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD IN CDB.
Fields contained in the PERSISTENT RESERVE OUT parameter list specify the information required to perform a particular
persistent reservation service action.
PARAMETER LIST LENGTH field
The PARAMETER LIST LENGTH field specifies the number of bytes of parameter data for the PERSISTENT RESERVE OUT command.
The parameter list shall be 24 bytes in length and the PARAMETER LIST LENGTH field shall contain 24 (18h), if the following conditions are true:
a) The SPEC_I_PT bit (see 3.14.3) is set to zero; and
b) The service action is not REGISTER AND MOVE.
If the SPEC_I_PT bit is set to zero, the service action is not REGISTER AND MOVE, and the parameter list length is not 24, then the command
shall be terminated with CHECK CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to PARAME
-
TER LIST LENGTH ERROR.
If the parameter list length is larger than the device server is able to process, the command should be terminated with CHECK CONDITION sta-
tus, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to PARAMETER LIST LENGTH ERROR.
Table 88 PERSISTENT RESERVE OUT command
Bit
Byte
7 6 5 4 3 2 1 0
0
OPERATION CODE (5Fh)
1
Reserved SERVICE ACTION
2
SCOPE TYPE
3
Reserved
4
5
(MSB)
PARAMETER LIST LENGTH
. . .
8
(LSB)
9
CONTROL