Abstract: In a computer system to which hardware units differing in control method are connected and which controls operations with a plurality of plug sections each appropriate to one or another of the different control methods, a control information memory stores a table for each type of hardware memorizing information as to which plug section should control the operation of that type. As an operating instruction is given specifying the hardware unit to be controlled, the control information memory determines the plug section with which to transfer the operating instruction with reference to this table, and transfers the operating instruction to this plug section.