Object Coordination Nets

Due to hardware developments, strong application needs and the overwhelming influence of the net in almost all areas, distributed systems, especially software systems, have become one of the most important topics for nowadays software industry. Unfortunately, distribution adds its share to the problems of developing complex software systems. Heterogeneity in both, hardware and software, concurrency, distribution of components and the need for interoperability between different systems complicate matters. Although subject to permanent changes, distributed systems have high requirements w.r.t. dependability and performance. Moreover, new technical aspects like resource management, load balancing and deadlock handling put an additional burden onto the developer. Nowadays programming languages are able to deal with these problems but work on a level of abstraction which is much too low. This makes complex systems hard to implement and much harder to maintain and change. Nowadays design methods fail to describe the specific properties of distributed systems in an adequate manner. One of the essential drawbacks of the methods which are around for some time now, is the lack of support for the dynamic aspects of distributed software systems