Patent ID: 8286031

Claim:
A storage apparatus that communicates with a host computer comprising: at least one processing unit; at least one switch unit connected to said at least one processing unit; and at least one memory unit connected to said at least one switch unit; wherein said at least one processing unit sends to said at least one memory unit a request packet for requesting data read or data write upon request of host computer, wherein said at least one memory unit receives the request packet via said at least one switch unit, outputs data or stores data in response to a request of the received request packet, and sends to said processing unit a response packet associated with the received request packet, wherein said at least one processing unit determine whether the response packet associated with the request packet has been received within a first time period from the sending of the request packet, wherein said at least one switch unit determines whether the response packet sent from said memory unit has passed through said switch unit within a second time period from a passage of the request packet associated with the response packet, and wherein the second time period is shorter than the first time period, wherein, if said processing unit determines that the response packet associated with the request packet has not been received within the first time period from the sending of the request packet, said at least one processing unit determines that a failure occurs in said at least one switch unit, and disables said at least one switch unit, wherein, if said at least one switch unit determines that the response packet has not passed through said at least one switch unit within said second time period from the passage of the request packet associated with the response packet, said at least one switch unit determines that a failure occurs in said at least one memory unit and disables said at least one memory unit.