Software Diversity In Computerized Control Systems

Software Diversity is one of the fault-tolerance means to achieve dependable systems. In this volume, some experimental systems as well as real-life applications of software diversity are presented. The history, the current state-of-the-art and future perspectives are given. Although this technique is used quite successfully in industrial applications, further research is necessary to solve some open questions. We hope to report on new results and applications in another volume of this series within some years. Acknowledgements The idea of the workshop was put forward by the chairpersons of IFIP WG lOA, J. -c. Laprie, J. F. Meyer and Y. Tohma, in January 1986, and the edi tor of this volume was asked to organize the workshop. This volume was edited with the assistance of the editors of the series, A. AviZienis, H. Kopetz and J. -C. Laprie, who also had the function of reviewers. Karlsruhe, October 1987 U. Voges, Editor Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Introduction U. Voges 2. Railway Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ERICSSON Safety System for Railway Control . . . . . . . . . . . . . . . . . . 11 G. Hagelin 3. Nuclear Applications . . . . . . . . . . . . . . . . . . . . . . 23 Use of Diversity in Experimental Reactor Safety Systems . 29 U. Voges The PODS Diversity Experiment . 51 P. G. Bishop 4. Flight Applications . . . . . . . . . . . . . . . . . . . . . . . . . 85 AIRBUS and ATR System Architecture and Specification. . 95 P. Traverse 5. University Research . . . . . . . . . . . . . . . . . . . 105 Tolerating Software Design Faults in a Command and Control System . . . . . . . . . . . . . . . . . . . . . . 109 T. Anderson, P. A. Barrett, D. N. Halliwell, M. R. Moulding DEDIX 87 - A Supervisory System for Design Diversity Experiments at UCLA . . . . . . . . . . . . . . . . . .

This book deals with the most important aspects of software diversity and its use in computerized control systems, including theoretical background, experiments, and industrial realizations (railway, flight and nuclear applications). Researchers describe their experiments with software diversity and explain their results, including benefits and drawbacks. Practitioners explain their use of it in real systems: why they use this means of fault-tolerance, and how they incorporate it into their systems. In addition to the papers the book contains a rather complete list of publications giving an overview on references about software diversity from its beginning until today. Therefore, this book is a complete description of the state of the art on the topic of software diversity.

Safety of Computer Control Systems 1985 (Safecomp '85): Achieving Safe Real Time Computer Systems presents the proceedings of the Fourth IFAC Workshop, held in Como, Italy, on October 1–3, 1985. This book discusses a wide range of topics ranging from direct process control through robotics to operator assistance. Organized into 28 chapters, this compilation of papers begins with an overview of the implementation of atomic actions by means of concurrent programming constructs. This text then examines the safety-related applications that usually demand the provision of redundant resources within the system. Other chapters consider the safe performance of an industrial robot system that relies on several factors. This book discusses as well the increasing demand for Computer Assisted Decision Making (CADM) both in engineering and service industries. The final chapter deals with the ways of reducing the effects of an error introduced during the design of a program. This book is a valuable resource for software engineers.

Safety of Computer Control Systems is a collection of papers from the Proceedings of the IFAC Workshop, held in Stuttgart, Germany on May 16-18, 1979. This book discusses the inherent problems in the hardware and software application of computerized control to automated systems safeguarding human life, property, and the environment. The papers discuss more specific concerns, such as railway systems, aircraft landing systems, nuclear power stations, chemical reactors, elevators, and cranes. The book also describes the safety and reliability of complex industrial computer systems together with an example showing the application of computers in power plants. One paper presents guidelines in documenting safety related computer systems that will help various parties who are involved in their purchase and operation. Another paper discusses how to detect failures in microcomputer systems such as memory violations and invalid operation code detectors. This book then concludes by discussing the necessity of inspecting process computers used in nuclear power plants, especially when computers are used in reactor protection, control rod, and authentication of log-in systems. This collection can be of interest for students of programming, process-computer analysts, heads of computer technology departments and institutions, and lecturers in industrial computer programming and design.

The market for safe, secure and reliable computer systems is expanding continuously and these Proceedings provide an opportunity to review the growth during the last decade and identify skills and technologies required for continued development in the area. The papers cover the experiences gained from specifying, creating, operating, and licensing computers in safety, security and reliability related applications. There are reviews of guidelines and industrial applications, with a section covering methods and tools used in designing, documenting, analysing, testing and assessing systems dependent on the SAFECOMP factors.

The proceedings of the fifth workshop in this subject continue the trend set by the previous four and discusses some of the current problems involved in the design and production of safe real-time computer systems. Topics covered include software quality assurance, software fault tolerance, design for safety, and reliability and safety assessment. Every paper details the theoretical and practical problems involved in the development of safe systems and should therefore be of interest to all those involved in systems design.

A reference guide for professionals or text for graduate and postgraduate students, this volume emphasizes practical designs and applications of distributed computer control systems. It demonstrates how to improve plant productivity, enhance product quality, and increase the safety, reliability, and

This innovative resource provides the most-comprehensive coverage of software fault tolerance techniques as it guides professionals through their design, operation and performance. It features an in-depth discussion on the advantages and disadvantages of specific techniques, so practitioners can decide which ones are best suited for their work.