Patent ID: 8683083

Claim:
A method of performing an input/output (I/O) processing operation at a host computer system configured for communication with a control unit, the method comprising: obtaining information relating to an I/O operation at a channel subsystem in the host computer system, the channel subsystem including at least one channel having a channel processor and a local channel memory; generating addressing information and forwarding the addressing information from the at least one channel to a network interface between the channel subsystem and at least one I/O device, the addressing information specifying a location in the local channel memory; forwarding an I/O command message to the at least one I/O device via the network interface; responsive to the I/O command message, receiving a data transfer request from the network interface that includes the addressing information; responsive to receiving the data transfer request, accessing one of a plurality of address control words (ACWs), each ACW specifying an address of a location in a host computer memory; and routing the data transfer request to the host memory location specified in the ACW.