Abstract: A computing system architecture includes a central processing unit having a channel, arithmetic and logic unit, a plurality of working registers, and control logic; a plurality of local storage registers; a main storage; an executable control store; one or more input/output devices; and a multiplexed cycle steal and interrupt request common poll bus.The storage and input/output devices communicate with and are controlled by the central processing unit over a looped, or unidirectional bus and control channel including a bus in, a bus out, an address and a six-bit code bus, and a plurality of control lines. Bus out is operated to address the executable control store and main storage, and to provide data to the input/output devices and the local storage registers. Bus in is shared by the input/output devices and all storage devices and registers for transferring data and control information to the central processing unit.