A storage device control unit for performing data writing/reading to/from a storage
device responding to requests coming from an information processor. The storage
device control unit includes: a communications interface section for carrying out
communications with the information processor; a storage device interface section
for carrying out communications with the storage device; a cache memory section
including first memory for storage of data coming and going between the information
processor and the storage device; and a connection section for connecting all together
the communications interface section, the storage device interface section, and
the cache memory section for communications thereamong. The connection section
is provided with second memory for storage of data same as the one stored in the
first memory. With such a structure, the inner process of the storage device control
unit can be effective.