Donald Bren School of Information and Computer Sciences

The Distributed Computer System (DCS) is a distributed timesharing system developed at the University of California Irvine. The system consists of multiple minicomputers coupled by a ring communications system. The present system has been used as a vehicle for research and development of distributed computer systems, and to support a limited amount of class programming.

The design objectives of the system are coherence, high availability through failsoft behavior, and low cost. Enhanced system availability is achieved through the distribution of hardware, software, and control. The distribution discipline of DCS also makes changes in system configuration natural. The failure of a redundant hardware or software network component is isolated; the remaining components continue to function. Mechanisms for the detection and the restart of the failed components allow the construction of fault tolerant services This paper describes the message functions and techniques that are used in the DCS and points out some possible evolutionary trends in message based distributed systems.