1. A storage system, comprising: a controller for responding to an I/O request from a host system and controlling the input and output of data to and from a storage device; a resource management processor for managing a chassis resource; and a system drive for storing main firmware of said resource management processor; wherein said controller performs comparative determination for comparing the revision of the main firmware installed in said resource management processor and the revision of the main firmware stored in said system drive and, when the revision of the main firmware installed in said resource management processor is older than the revision of the main firmware stored in said system drive, renews the main firmware installed in said resource management processor to the main firmware stored in said system drive.