The SIGNAL software environment for real-time system specification, design, and implementation

Reactive systems, i.e. systems which interact permanently with their environment, are considered. The specification, design, and implementation of such reactive systems require the following tools: a concurrent programming or specification language; a powerful formal tool which is able to verify, prove the correctness of, or even synthesize, the logic and synchronization mechanisms which should control the reactive system being designed; and a powerful tool which is able to transform the hierarchical structure of the specification in order to match a particular target architecture. The SIGNAL software environment and its formal calculus system for performing these tasks are presented. The principles of the SIGNAL synchronous language and its calculus system, which is based on formal manipulation of nuclear dynamical systems over the finite field of modulo 3 integers, is outlined. A prototype workstation where automatic mapping of a SIGNAL program onto a multitransputer target architecture is performed with the aid of a sophisticated graphic environment is presented. The impact of such tools on the future of real-time system specification, design, and implementation is discussed