INPUT/OUTPUT CONTROLLER FOR A DATA PROCESSING SYSTEM

An I/O controller is provided for transferring data between a host processor and a plurality of I/O devices wherein the host processor generates a transfer command and each of the plurality of I/O devices generates multiple asynchronous service requests for transfer to the host processor. Control circuitry is provided for controlling the transfer of the service requests from the plurality of I/O devices to the host processor. The control circuitry generates a host processor interrupt signal for application to the host processor, such that in response to the host processor interrupt signal, the host processor generates the transfer command to allow the control circuitry to transfer the service requests to the host processor.