Network Aspects of the Fermilab Control System

The control system of the Fermi National Accelerator is a heavily computerized network of distributed processors. One part of the control system includes a multidrop network of eleven Lockheed MAC-16 processors, a Digital Equipment Corporation PDP-ll computer, a Xerox 530, and a Control Data 6600 system. These computers exchange information using serial hardware and dedicated cable buses. This paper attempts to explain the individual functions of the central processing units in this network, describes the message protocols for computer communications, and deduces design guidelines for future distributed processing control systems.