US Patent 7490185 Data processing system, access control method, and access control device

A data processing system able to raise the access efficiency to a memory when a plurality of processor access to the memory will be provided. An arbitration program executed by one input/output processing device determines a priority order for the access requests to the RAIDs so as to give the access permission with the highest priority to the access request linked with the reproduction port. The arbitration program notifies the result of the determination to the arbitrated programs executed by the other input/output processing devices.