In an information processing system having a data processing apparatus, a control unit for a cache memory, and a storage unit for storing a record, respectively interconnected together, wherein when the control unit receives from the data processing apparatus a write request for a record to be written and if the record to be written is not being stored in the cache memory, the control unit receives a data to be written in the object record from the data processing apparatus and stores the received data in the cache memory. After notifying the data processing apparatus of a completion of a data write process, the control unit checks if the object record in which the data stored in the cache memory is being stored in the storage unit, if the object record is being stored in the storage unit, the data in the cache memory is written in the storage unit, and if not, the data in the cache memory is not written and such effect is notified to the data processing apparatus.