A computer body outputting a predetermined number of address signals A0 to A11 and a plurality of select signals CSO and CSI, generates a memory select signal CS and an additional address signal A12 added to the signals A0 to A11 according to the inputted signals CSO and CSI, and provides the signal CS, signal A12, and signals A0 to AI1 to a 256-megabit SDRAM (memory), so that the computer body can access the corresponding data. The computer body can access the data corresponding to the generated additional address signal A12 and predetermined number of the address signals A0 to A11.