Position statement on concurrent objects for massively parallel architectures
This discussion reviews some features of objects and actors and attempts to answer remarks made by Carl Hewitt [Hewitt, 1988} concerning the superiority of actors over objects. Our interest in this discussion stems from research on a multicomputer being designed at Mississippi State University called the Mapped Array Differential Equation Machine (MADEM). The architecture for this floating-point-intensive scientific problem solver supports a finegrained reactive message-passing programming model. Message delivery and process scheduling are performed by a node's i/o processor, which operates concurrently with a high performance numeric processor. In choosing our model for concurrent computation we were influenced by research at Cal Tech and by the work of William Dally [Dally, 1986]. 3. Concurrency within computational agents