ARCADE: A Platform for Heterogeneous Distributed Operating Systems

A new approach to the design of distributed and multiprocessor operating systems is presented. This approach, called ARCADE, addresses the problems inherent in an interconnection of heterogeneous computers. It also allows efficient operation of uniprocessors and shared-memory multiprocessors. ARCADE specifies the conceptual structure and functional behavior of a platform which supports cooperating tasks. Operating systems and other distributed processes can then be built as collections of such tasks. A prototype implementation of this platform has shown it to be an effective basis for distributed computing. This paper introduces ARCADE and summarizes its design and potential applications. 1. Goals of the ARCADE Project The primary goal of the ARCADE project is to provide a software platform on which distributed applications, including operating systems, can be built. An important decision in the design phase of this project was to view applications as collections of independent, cooperating tasks. ARCADE itself is simply the underlying environment that supports these tasks and allows them to interact with each other across machine and network boundaries. The most ambitious objective of the project is to provide an environment in which tasks can cooperate in a uniform and effective manner even if they reside on machines with different hardware architectures. This paper describes the experiences of the authors in designing and implementing a system which satisfies these goals. The ensuing section of this paper summarizes several important projects with goals similar to those of ARCADE. This is followed by an explanation of ARCADE's approach to distributed computing. The next section outlines the major elements of ARCADE and explains why they were developed. The current state of ARCADE, including its implementation, performance characteristics and operating system services, is then discussed. Finally, the future of the project is outlined.