Patent ID: 7146540

Claim:
A disc array device comprising: a channel interface control adaptor connected to a host computer and having a redundant constitution as an internal constitution in which data transfer and control are performed by a process of a microprocessor; a plurality of disc drives for storing data; a disc drive interface control adaptor connected to said disc drives and having a redundant constitution as an internal constitution in which data transfer and control are performed by a process of a microprocessor; a cache memory in which data to be transferred between said host computer and each of said plurality of disc drives is temporarily stored; and a cache path switch connected to said channel interface control adaptor, the disc drive interface control adaptor, and the cache memory and making an internal bus connection, wherein said channel interface control adaptor, said disc drive interface control adaptor, said cache memory, and said cache path switch each has a data transfer interface and a diagnostic interface, by at least one microprocessor of said channel interface control adaptor having the redundant constitution, a hardware diagnosis of a part in said channel interface control adaptor is made, and hardware diagnoses of a part in said cache memory and a part in said cache path switch are made through said diagnostic interface of said channel interface control adaptor, and by at least one microprocessor of said disc drive interface control adaptor having the redundant constitution, a hardware diagnosis of a part in said disc drive interface control adaptor is made, and hardware diagnoses of a part in said cache memory and a part in said cache path switch are made through said diagnostic interface of said disc drive interface control adaptor.