A processor transmits, to a communication control module, at least one write request packet with which at least one data block element configuring a data block is respectively associated, and updates a first counter to a value corresponding to the number of the transmitted write request packets. The communication control module writes a data block element associated with the write request packet to a cache memory, updates a third counter to a value corresponding to the number of the transmitted data block elements, and reflects the third counter to a second counter. The processor determines that the data block is written to the cache memory when the second counter reaches the first counter after all write request packets are transmitted.