Horst F. Wedde und Arnim Wedig
Explicit Modeling of Influences, and of Their Absence, in Distributed Systems
Forschungsbericht, University of Dortmund, 2001-03
Specific problems in practical distributed system design arise from incomplete information about the cooperation requirements, up to, or even beyond, the final design stage. Events in components will occur, or they may occur, depending on (local) user decisions. The latter may also not occur, as a result of yet unknown external influences or design faults. Adequate formal modeling tools should allow for distinguishing between such different event types. Our approach for this purpose to be introduced here is the formal model of I-Systems. As a particularly relevant and unique feature, the presence as well as the absence of interactional influences (as part of distributed cooperation requirements) can be explicitly modeled, with no side effects. A non-trivial synchronization problem is modeled incrementally in order to demonstrate both the modeling and analysis capabilities in I-Systems.