Interpreting Distributed System Architectures using VDM++ – A Case Study

The complexity of real-time embedded systems is increasing in particular due to the use of distributed system architectures for their implementation. Notations to describe these software intensive distributed computer systems at the system-level are at best still in their infancy. An extension to the Vienna Development Method (VDM) is proposed to address the problem of analyzing deployment of software on distributed hardware. The extension enables the description of systems rather than just software. The language contains primitives for describing concurrent thread-based software components that are explicitly deployed on one or more processors which in turn are interconnected by one or more networks. The value of this modelling approach is illustrated using a case study for a missile counter measures system. We describe different alternative distributed architectures and we explore the projected timing properties for given scenarios of missile attacks.