With the advent of large-scale parallel computing systems, making parallel programs fault-tolerant becomes an important problem, because the probability of a failure increases with the number of processors. In this paper, we describe a very simple scheme for rendering a class of parallel Orca programs fault-tolerant. Also, we discuss our experience with implementing this scheme on Amoeba. Our approach works for parallel applications that are not interactive. The approach is based on making a globally consistent checkpoint from time to time and rolling back to the last checkpoint when a processor fails. Making a consistent global checkpoint is easy in Orca, because its implementation is based on reliable broadcast. The advantages of our approach are its simplicity, ease of implementation, low overhead, and transparency to the Orca programmer. 1
