Patent ID: 7523354

Claim:
A disk controller comprising a plurality of controller modules for controlling data transfer between a host processor and a disk device, each controller module having one or more channel adapters having an interface with the host processor, one or more device interfaces having an interface with the disk device, and one or more transfer circuits for communication, said plurality of controller modules having a function to communicate with each other through a communication path using said one or more transfer circuits; at least one of said controller modules comprising: a path obstruction determination unit for obstructing a part in which an anomaly occurs when the anomaly occurs on said communication path, and, when said plurality of controller modules cannot communicate between them due to the obstruction of the part, for determining an object to be separated in a way that prioritizes a controller module which retains data that has not been duplicated over a controller module which retains data that has been duplicated among the controller modules which cannot communicate; and a separation control unit for disabling a control module that is determined to be an object to be separated by said path obstruction determination unit.