Patent ID: 7650393

Claim:
An information processing system, comprising: a first controller and a second controller accepting requests from a plurality of sources, and writing and reading data to/from a storage device in response to these requests; wherein the first controller returns a response to a request from at least one first source of the plurality of sources, to the first source, and does not return a response to a request from a second source other than the first source, to the second source; and wherein the second controller does not return a response to a request from the first source to the first source receiving a response from the first controller, and returns a response to a request from the second source to the second source not receiving a response from the first controller, wherein the first controller sends a succession request and first ID to identify the first source to the second controller, wherein the first controller also issues an inquiry to the second controller as to whether or not succession is possible, wherein the second controller issues a response to the first controller to the effect that succession is possible if the load on the second controller is equal to or less than a prescribed size, and wherein, when the first controller does not receive a response to the effect that the succession is possible, source IDs other than the first source ID are also set such that the response thereto is permitted, and thus the first controller returns a response also to requests from the sources other than the first source.