1. A storage system comprising a plurality of kinds of exchangeable functional parts for transferring data with a host device, wherein said functional parts include: channel adapter parts which function to communicate data with said host device; cache memory parts which function to temporarily store data that is transferred from said channel adapter parts; disk adapter parts having a control function to store data stored in said cache memory parts in a plurality of disk drives; switch parts which function to transfer data mutually among said channel adapter parts, said cache memory parts and said disk adapter parts; and a shared memory part in which control information is written concerning data stored in said cache memory parts, from said channel adapter parts and said disk adapter parts; wherein each of said functional parts includes memory means, and wherein each of said memory means stores event information which is configured so as to exhibit a correspondence between an event which has occurred in respective functional parts and packaging position information of each of said respective functional parts.