Patent ID: 7519770

Claim:
A disk array controller comprising: a first selector unit connected to k (k being a natural number) host interface units for channels of a first type, p (p being a natural number) host interface units for channels of a second type, m (m being a natural number) disk interface units for the channels of the first type, and n (n being a natural number) host interface units for channels of a third type; a second selector unit connected to host interface units for the channels of the first type, said k host interface units being different from the host interface units connected to the first selector, p host interface units for the channels of the second type, said p host interface units being different from the host interface units connected to the first selector, m disk interface units for channels of the first type, said m disk interface units being different from the disk interface units connected to the first selector unit, and n host interface units for channels of the third type, said n host interface units being different from the host interface units connected to the first selector; and a cache memory unit connected, via the first selector unit but not the second selector unit, to the host interface units and disk interface units that are also connected to the first selector and connected, via the second selector unit but not the first selector unit, to the host interface units and disk interface units that are also connected to the second selector.