The influence of coordination on program structure

We examine the inherent properties of some of the most popular coordination models of today and show how they contribute to the difficulty of systematic construction of coordination protocols for the cooperation of concurrent processes, as explicit, tangible pieces of software. They include the object oriented models of communication and the generative tuple space paradigm of models such as Linda. We then describe a new generic model: Idealized Worker Idealized Manager (IWIM) and discuss its advantages for coordination of concurrent activities, especially in control oriented applications. We demonstrate its "completeness" by showing that it can trivially emulate other well known communication and coordination models. Separation of computation and coordination code into different program modules is one of the important properties of this model, which is fully exploited in the pure coordination language MANIFOLD.