McROSS-A multi-computer programming system* by ROBERT H. THOMAS and D. AUSTIN HENDERSON

This paper describes an experimental "distributed" programming system which makes it possible to create multi-computer programs and to run them on computers connected by the ARPA computer network (ARPANET).1 The programming system, which is called McROSS (for Multi-Computer Route Oriented Simulation System), is an extension of a singlecomputer simulation system for modelling air traffic situations2 developed by Bolt, Beranek and Newman, Inc. (BBN) as a tool for air traffic control research. The McROSS system provides two basic capabilities. One is the ability to program air traffic simulations composed of a number of "parts" which run in geographically separated computers, the distributed parts forming the nodes of a "simulator network." The second is the ability of such a simulator network to permit programs running at arbitrary sites in the ARPANET to "attach" to particular nodes in it for the purpose of remotely· monitoring or controlling the node's operation. The McROSS distributed programming system is unique in several ways: