For example, this computer system is a personal computer constituted by a CPU 1401 for controlling arithmetic processing, an input section 1402 such as a keyboard, a pointing device, or a microphone, an output section 1403 such as a display or a loudspeaker, a ROM 1404 and a RAM 1405 as a main memory, a hard disk unit 1406, a floppy disk unit 1407, and an optical disk unit 1408 as an external memo