System and method for restoring a status of an apparatus controlled by multiple commands
A system includes first, second, and third apparatuses. The second apparatus converts a first control-command received from the first apparatus to second control-commands compatible with the third apparatus, requests the third apparatus to perform the second control-commands, and notifies the first apparatus of a normal finish of the first control-command when all the second control-commands have finished normally, so that the first apparatus updates a first status of the third apparatus that is held by the first apparatus. The third processor updates a second status of the third apparatus that is held by the third apparatus, upon finishing each second control-command, generates reverse-commands for restoring a result of having executing the second control-commands to a status prior to executing the second control-commands, and, when all the second control-commands have not been executed, restores the second status to a status prior to having executed the second control-commands by executing the reverse-commands.
1. A system for restoring a status of an apparatus controlled by multiple commands, the system comprising:
a first apparatus;
a second apparatus connected to the first apparatus; and
a third apparatus connected to the second apparatus, wherein
the first apparatus includes:
a first memory configured to store first apparatus-status information indicating a status of the third apparatus that is updated by the first apparatus,
a first processor coupled to the first memory, configured to:
provide the second apparatus with a first control command for controlling the third apparatus, and
update the apparatus-status information stored in the first memory when information indicating a normal finish of the first control command is received from the second apparatus;
the second apparatus includes a second processor configured to:
convert the first control command received from the first apparatus to a plurality of second control commands compatible with the third apparatus,
provide the third apparatus with a request to perform the plurality of second control commands, and
transmit information indicating a normal finish of the first control command to the first apparatus when all of the plurality of second control commands finish normally; and
the third apparatus includes:
a second memory configured to store second apparatus-status information indicating a status of the third apparatus that is updated by the third apparatus, and a reverse command for restoring a result of executing each second control command to a result prior to executing the each second control command,
a third processor coupled to the second memory, configured to:
execute the plurality of second control commands, based on a request from the second apparatus, and update the second apparatus-status information in connection with finish of each second control command,
transmit a normal-finish notification indicating a normal finish of the plurality of second control commands to the second apparatus,
generate a reverse command in connection with execution of each second control command, and store the generated reverse commands in the second memory, and
in a case where all of the plurality of second control commands have not been executed, cause the second apparatus-status information to be restored to information indicating a status prior to execution of the plurality of second control commands by executing control based on the reverse commands stored in the second memory.
2. The system of claim 1 , wherein
the third processor executes control based on the one or more reverse commands stored in the second memory in a case where the plurality of second control commands have not normally finished within a predetermined period.
3. The system of claim 1 , wherein
the third processor executes control based on the one or more reverse commands stored in the second memory, upon receiving from the second apparatus a notification that transmission of information indicating a normal finish of the first control from the second apparatus to the first apparatus has failed.
4. The system of claim 1 , wherein
the one or more reverse commands are stored in a nonvolatile region of the second memory; and
when restarting the third apparatus, the third processor executes control based on the one or more reverse commands when the one or more reverse commands are stored in the second memory.
5. A method for restoring a status of a third apparatus controlled by multiple commands in a system, the system including a first apparatus, a second apparatus connected to the first apparatus, and the third apparatus connected to the second apparatus, the method comprising:
causing the first apparatus to:
store first apparatus-status information indicating a status of the third apparatus that is updated by the first apparatus,
provide the second apparatus with a first control command for controlling the third apparatus, and
update the apparatus-status information when information indicating a normal finish of the first control command is received from the second apparatus;
causing the second apparatus to:
convert the first control command received from the first apparatus to a plurality of second control commands compatible with the third apparatus,
provide the third apparatus with a request to perform the plurality of second control commands, and
transmit information indicating a normal finish of the first control command to the first apparatus when all of the plurality of second control commands finish normally; and
causing the third apparatus to:
store second apparatus-status information indicating a status of the third apparatus that is updated by the third apparatus, and a reverse command for restoring a result of executing each second control command to a result prior to executing the each second control command,
execute the plurality of second control commands, based on a request from the second apparatus, and update the second apparatus-status information in connection with finish of each second control command,
transmit a normal-finish notification indicating a normal finish of the plurality of second control commands to the second apparatus,
generate a reverse command in connection with execution of each second control command, and store the generated reverse commands, and
in a case where all of the plurality of second control commands have not been executed, cause the second apparatus-status information to be restored to information indicating a status prior to execution of the plurality of second control commands by executing control based on the reverse commands stored in the third apparatus.