Limitations of Synchronous Communication with Static Process Structure in Languages for Distributed Computing

Abstract

Modules in a distributed program are active, communicating entities. A language for distributed programs must choose a set of communication primitives and a structure for processes. This paper examines one possible choice: synchronous communication primitives (such as rendez-vous or remote procedure call) in combination with modules that encompass a fixed number of processes (such as Ada tasks or UNIX processes). An analysis of the concurrency requirements of distributed programs suggests that this combination imposes complex and indirect solutions to common problems and thus is poorly suited for applications such as distributed programs in which concurrency is important. To provide adequate expressive power, a language for distributed programs should abandon either synchronous communication primitives or the static process structure.