Good programming language support can simplify the task of writing fault-tolerant distributed software. Here, an approach to providing such support is described in which a general high-level distributed programming language is augmented with mechanisms for fault tolerance. Unlike approaches based on sequential languages or specialized languages oriented towards a given fault-tolerance technique, this approach gives the programmer a high level of abstraction, while still maintaining flexibility and execution efficiency. The paper first describes a programming model that captures the important characteristics that should be supported by a programming language of this type. It then presents a realization of this approach in the form of FT-SR, a programming language that augments the SR distributed programming language with features for replication, recovery, and failure notification. In addition to outlining these extensions, an example program consisting of a data manager and its associated stable storage is given. Finally, an implementation of the language that uses the x-kernel and runs standalone on a network of Sun workstations is discussed. The overall structure and several of the algorithms used in the runtime are interesting in their own right.>

The design of FT-SR, a programming language based on SR and oriented toward constructing fault-tolerant distributed systems, is presented. The language, which is based on the existing SR language, is unique in that it has been designed to support equally well any of the programming paradigms that have been developed for this type of system, including the object/action model, the restartable action paradigm, and the state machine approach. To do this, the language is designed to support the implementation of systems modeled as collections of fail-stop atomic objects. Such objects execute operations as atomic actions except when a failure or series of failures cause underlying implementation assumptions to be violated; in this case, notification is provided. An example program consisting of a data manager and its associated stable storage is given.>