Theoretical aspects of coordination languages

Abstract

About coordination The emergence of high bandwidth network technology has fuelled the development of distributed computing and concurrent programming. Coordination languages are a new class of programming languages which offer a solution to the problem of managing the interaction among concurrent programs. Gelemter and Carrier0 coined the term Coordination in the following slogan: Concurrent programming = Computation + Coordination. They formulated this equation when introducing the coordination language Linda. The intent is that there should be a clear separation between the components of the computation and their interaction in the overall program or system. On the one hand, this separation facilitates the reuse of code; on the other hand, the same patterns of interaction occur in many different problems - so it might be possible to reuse the coordination component as well! Coordination languages are not general purpose programming languages; rather, they are often defined as language extensions or scripting languages and they are exclusively concerned with coordination issues. In defining coordination languages there are a number of issues which must be addressed: 1. what is being coordinated? 2. what are the media for coordination? 3. what are the protocols and rules used for coordination? Coordinated entities: The coordinated entities are usually active - agents or processes. Coordination of agents should not require reprogramming of the agents; the coordina- tion mechanism is a wrapper around the existing, independent agents. The agents may have been programmed in a variety of different programming languages.