Specification and Verification of Distributed Real-Time Systems

Abstract

What makes the design of distributed real-time systems hard and their validation expensive is their great complexity. Thereby, complexity comprises things such as the degree of dispersion and the diversity of the system components. Timing constraints and reliability aspects, beside many more topics, are as important as correct functionality but render more difficult. Therefore, suitable ways and means must be available from the very beginning of the development process to support the developer in his creative work to take adequate decisions at the various stages of system development. Formal methods are needed to gain the benefits from mathematically based techniques to specify systems.

Compositionality is now seen as an important property of formal specification languages and formal proof methods in the area of distributed real-time systems. But many such languages are derivatives or extensions of traditional sequential ones. In this paper we present a language supporting a property-oriented approach for the specification, construction, and verification of distributed real-time systems, called RDSL. Main constituents of RDSL are: First RSL, a three-sorted modal logic for the specification of system requirements, i. e. the required behaviour of a system. Second DSL, a combinator language for the specification of system design, i. e. the structure of a system designed to achieve a certain behaviour. Because referential transparency is one characteristic of DSL a compositional proof system can naturally be provided as third part of RDSL. The principle of separation of concerns is more rigourously incorporated in RDSL than in other approaches.