Patent ID: 7581060

Claim:
A storage device control apparatus comprising: a plurality of channel control units, each with a host interface controller formed therein for receiving data input/output (I/O) requests from a first host computer; a plurality of disk control units, each with a disk interface controller formed therein for performing I/O control of data to first storage volumes storing data in response to the data I/O requests; a plurality of storage control units, each with a host interface controller for receiving data I/O requests from a second host computer, a disk interface controller for performing I/O control of data to second storage volumes, and a memory formed therein for temporarily storing data being transferred between said host interface controller and said disk interface controller; and an internal connection part which is able to connect to and/or disconnect from each of said channel control units, said disk control units, and said storage control units independently, wherein, upon receipt of a data I/O request from the first host computer to a channel control unit, said host interface controller, included in said channel control unit, analyzes the data I/O request, and based on the analysis, determines whether the data I/O request is a read request or a write request, determines an address of data to be accessed, and sends a command according to whether the data I/O request is a read request or a write request to one of the disk control units, and wherein, upon receipt of a data I/O request from the second host computer to a storage control unit, said host interface controller, included in said storage control unit, analyzes the data I/O request, and based on the analysis, determines whether the data I/O request is a read request or a write request, determines an address of data to be accessed, sends a command according to whether the data I/O request is a read request or a write request to said memory if the data to be accessed is stored in said memory, and sends a command according to whether the data I/O request is a read request or a write request to the disk interface controller included in said storage control unit if the data to be accessed is not stored in said memory.