A distributed architecture for the input/output system for a multiprocessor system provides for equal and democratic access to all shared hardware resources by both the processors and the external interface ports of the multiprocessor system. This allows one or more input/output concentrators attached to the external interface ports to have complete access to all of the shared hardware resources across the multiprocessor system without requiring processor intervention. The distributed input/output system provides for communication of data and control information between a set of common shared hardware resources and a set of external data sources. The result is a highly parallel multiprocessor system that has multiple parallel high performance input/output ports capable of operating in a distributed fashion. The distributed architecture also permits both processors and external interface ports to access all of the shared data structures associated with the operating system that contain the input/output control information.