Parallel Multiset Processing: FRom Explicit Coordination to Chemical Reaction

The author has been involved for more than fifteen years in the design, study and implementation of coordination program structures. These structures were designed with a clear conviction that data structuring and program structuring were two closely related issues. Very early, it was recognized that set data structuring was a key concept for the design of programs with a high potential for parallelism. This paper offers a personal perspective of this research activity which culminated with the Gamma formalism.