9 Springer-Verlag 1989 Probabilistic clock synchronization

operating systems and pro-gramming methodology in France, and working on the specification, design, and verifi-cation of fault-tolerant pro-grams in England, he joined IBM in 1982. Since then he has worked in the area of fault-tol-erant distributed protocols and systems. He has participated in the design and implementation of a highly available system prototype at the Almaden Research Center and has reviewed and consulted for several fault-tolerant distributed system designs, both in Europe and in the American divisions of IBM. He is now a technical leader in the design of a new U.S. Air Traffic Control System which must satisfy very stringent availability requirements. Abstract. A probabilistic method is proposed for reading remote clocks in distributed systems ub-ject to unbounded random communication delays. The method can achieve clock synchronization precisions uperior to those attainable by previous-ly published clock synchronization algorithms. Its use is illustrated by presenting a time service which maintains externally (and hence, internally) syn-chronized clocks in the presence of process, com-munication and clock failures