PURPOSE: To use the different files based on plural OSs or device types by having accesses to the files based on these OSs and device types and converting the files into other ones of other OSs and device types.

CONSTITUTION: A display device 1 is provided together with a console 2, a CPU main body 3, a main memory 4, an external storage 5, an OS basic drive device 6, and a conversion drive device 7. Then one of plural OSs or device types shown by a menu display means is selected and designated, and an individual driver corresponding to the designated OS or device type is started and an access is given to the file of the designated OS or device type. Then an access is given to the file set based on the OS or device type designated by the return information, and this designated file is converted into another file according to another OS or device type. As a result, the files obtained by plural different OSs and device types can be converted into a file used for a specific OS or device type. Thus plural different files can be used.