Formal methods and tools for the development of distributed and real time systems : Esprit Project 3096 (SPEC)

The Basic Research Action No. 3096, Formal Methods snd Tools for the Development of Distributed and Real Time Systems, is funded in the Area of Computer Science, under the ESPRIT Programme of the European Community. The coordinating institution is the Department of Computing Science, Eindhoven University of Technology, and the participating Institutions are the Institute of Computer Science of Crete. the Swedish Institute of Computer Science, the Programmimg Research Group of the University of Oxford, and the Computer Science Departments of the University of Manchester, Imperial College. Weizmann Institute of Science, Eindhoven University of Technology, IMAG Grenoble. Catholic University of Nijmegen, and the University of Liege. This document contains the synopsis. and part of the sections on objectives and area of advance, on baseline and rationale, on research goals, and on organisation of the action, as contained in the original proposal, submitted June, 198S. The section on the state of the art (18 pages) and the full list of references (21 pages) of the original proposal have been deleted because of limitation of available space

Compositional semantics for real-time distributed computing

We give a compositional denotational semantics for a real-time distributed language, based on the linear history semantics for CSP of Francez et al. Concurrent execution is not modelled by interleaving but by an extension of the maximal parallelism model of Salwicki, that allows the modelling of transmission time for communications. The importance of constructing a semantics (and in general a proof theory) for real-time is stressed by such different sources as the problem of formalizing the real-time aspects of Ada and the elimination of errors in real-time flight control software ([Sunday Times 7-22-84])

A compositional proof theory for real-time distributed message passing

A compositional proof system is given for an OCCAM-like real-time programming language for distributed computing with communication via synchronous message passing. This proof system is based on specifications of processes which are independent of the program text of these processes. These specifications state (1) the assumptions of a process about the behaviour of its environment, and (2) the commitments of that process towards that environment provided these assumptions are met. The proof system is sound w.r.t a denotational semantics which incorporates assumptions regarding actions of the environment, thereby closely approximating the assumption/commitment style of reasoning on which the proof system is based. Concurrency is modelled as maximal parallelism ; that is, if a process can proceed it will do so immediately. A process only waits when no local action is possible and no partner is available for communication. This maximality property is imposed on the domain of interpretation of assertions by postulating it as separate axiom. The timing behaviour of a system is expressed from the viewpoint of a global external observer, so there is a global notion of time. Time is not necessarily discrete