A fault-tolerant server on MACH

Abstract

This paper describes a fault-tolerant server (FTS) implemented on top of a distributed operating system, the MACH microkernel. FTS provides hardware fault-tolerance using software mechanisms. The state machine approach, also called process replication, has been used as fault-tolerance model. A fault-tolerant process is implemented as a set of replicas executing in different nodes. The process will offer full functionality as long as one replica is alive. To get all replicas behaving in the same way, a distributed consensus protocol has been used in FTS. FTS provides to user applications with a client-server communication mechanism where replications is transparent.