The U.S. Army operates a field laboratory where realistic combat simulations between jet aircraft, helicopters, tanks, and infantry can be closely observed. Lasers are used to simulate the weapons carried by as many as 200 players. Laser firings, hits, and player location are monitored by a telemetry and range measurement system controlled by a computer network. Player combat engagements are evaluated in real-time by the computer network and the results returned to the player. The computer network primarily consists of 12 PDP-11/45s and a DEC-1060. The PDP-11/45s operate under RSX-llM and RSX-11S. Each PDP 11/45 processor communicates with the other processors through a 32K shared memory. Application software includes telemetry polling and control, player position calculation, real-time casualty assessment, and various monitors and displays. The major focus of this paper is the development of a successful high speed, general purpose interprocessor/intertask data communication system, operating within the shared memories, which facilitates concurrent processing of data with minimal overhead.