Cliff B. Jones

Cliff B Jones, Alan Burns

The application considered is mixed-criticality scheduling. The core formal approaches used are Rely-Guarantee conditions and the Timeband framework; these are applied to give a layered description of job scheduling which includes resilience to jobs overrunning their expected execution time. A novel formal modelling idea is proposed to handle the relationship between actual time and its approximation in hardware clocks.

Cliff B. Jones, Martyn Thomas

UK researchers have made major contributions to the technical ideas underpinning formal approaches to the specification and development of computer systems. Perhaps as a consequence of this, some of the significant attempts to deploy theoretical ideas into practical environments have taken place in the UK. The authors of this paper have been involved in formal methods for many years and both have tracked a significant proportion of the whole story. This paper both lists key ideas and indicates where attempts were made to use the ideas in practice. Not all of these deployment stories have been a complete success and an attempt is made to tease out lessons that influence the probability of long-term impact.

Manuel Mazzara, Cliff Jones, Alexei Iliasov

This paper reviews the major lessons learnt during two significant pilot projects by Bosch Research during the DEPLOY project. Principally, the use of a single formalism, even when it comes together with a rigorous refinement methodology like Event-B, cannot offer a complete solution. Unfortunately (but not unexpectedly), we cannot offer a panacea to cover every phase from requirements to code; in fact any specific formalism or language (or tool) should be used only where and when it is really suitable and not necessarily (and somehow forcibly) over the entire lifecycle.