Patent ID: 8006040

Claim:
A data storage device, comprising a storage device having a single or a plurality of storage media storing data to be processed in a host computer; and a control device connected to the storage device and the host computer to control data transfer there between, wherein the control device further comprises: a first interface control circuit for controlling a connection to the host computer, a second interface control circuit for controlling a connection to the storage device, a microprocessor connected to the first and the second interface control circuits, a local memory connected to the microprocessor, and a cache memory connected to the microprocessor, wherein the microprocessor: determines a transfer size of a read request from the host computer, the transfer size indicating (i) an amount of data requested by the read request, and (ii) that the read request has a sequential access property; compares the transfer size of the read request with a preset pre-fetch determination size; determines that the read request has the sequential access property when the transfer size of the read request is the same as the preset pre-fetch determination size, stores data designated by the read request in a first storage area in the cache memory, sends the data designated by the read request to the host computer, and pre-fetches, in response to the determination that the read request has the sequential access property, data to a second storage area in the cache memory succeeding the data designated by the read request stored in the first storage area.