The memories connected to the CPU 10 are, for example, 4 types of memories, that is, a 64 MB memory device 15 and 96 MB memory device 16, as non-volatile memories, and an 8 MB memory device 14 as a high-speed SRAM, and a 64 MB memory device 18 as a DRAM or FCRAM. The relationship between the memory devices 16 and 14 corresponds to the relationship shown in FIG. 3, and the memory device 16 has an a