DATA SAVING SYSTEM FOR DUPLEX DATA RECORDER

PURPOSE:To prevent business from being delayed by saving data by executing a data output request immediately after finishing the copy processing of an area under copying when an area, to which the output is requested from a user program, is overlapped with this area under copying. CONSTITUTION:An input/output control means 3 switches a sub device 5 and a saving device 6 while responding a save request from a data save processing means 1, and the data on the sub device is remained as saved data as it is. Then, the data on a main storage device 4 is written to the switched sub device 5. In such a case when there is the output request of the data from the user program to a data recorder, it is decided whether the output request competes the data under processing or not, and when the output request does not compete, the data is outputted to the main device 4 and the sub device 5 according to the output request. When the output request competes, the data is outputted according to the output request after finishing the competitive data processing. Thus, the data can be saved without any trouble in the business processing.