Patent ID: 8089487

Claim:
A storage control device comprising a plurality of controllers, wherein each of said controllers comprises: a host communication control unit for performing communication with a host device; a subordinate communication control unit for performing communication with a plurality of storage devices which store data used by said host device; a cache memory for temporarily storing data transmitted from said host communication control unit; an access request processing unit which, when an access request has been received from said host device via said host communication control unit, processes said access request by accessing said plurality of storage devices via said subordinate communication control unit, and by executing predetermined data processing based on control program; and a program storage unit which stores said control program corresponding to said access request processing unit, in which said access request processing unit needs to restart after updating the control program; said storage control device further comprising: a mutual communication path for connecting said controllers; an update control unit for updating said control program which is stored in said program storage unit; and a processing path changeover unit connecting said host communication control unit and said access request processing unit, which changes over between: (1) a normal mode in which said host communication control unit and said access request processing unit are respectively connected in each said controller; and (2) an updating mode in which said host communication control unit of one controller is connected via said mutual communication path to said access request processing unit of another controller; and, wherein when updating said control program that said program storage unit in said one controller stores, data in the cache memory within said one controller is sent to the cache memory within said other controller; based on a command from said update control unit, said processing path changeover unit changes over said normal mode to said updating mode and processes said access request received by said host communication control unit of said one controller by means of said access request processing unit of said other controller.