Bücher der Reihe Dependable Computing and Fault-Tolerant Systems

This volume contains the papers presented at the Second International Work ing Conference on Dependable Computing for Critical Applications, sponsored by IFIP Working Group lOA and held in Tucson, Arizona on February 18-20, 1991.

This volume contains the articles presented at the Fourth InternationallFIP Working Conference on Dependable Computing for Critical Applications held in San Diego, California, on January 4-6, 1994.

For the editors of this book, as well as for many other researchers in the area of fault-tolerant computing, Dr. William Caswell Carter is one of the key figures in the formation and development of this important field.

7 ERICSSON Safety System for Railway Control . 23 Use of Diversity in Experimental Reactor Safety Systems . Voges The PODS Diversity Experiment . 105 Tolerating Software Design Faults in a Command and Control System . Moulding DEDIX 87 - A Supervisory System for Design Diversity Experiments at UCLA .

For the second time the International Workshop on Responsive Com puter Systems has brought together a group of international experts from the fields of real-time computing, distributed computing, and fault tolerant systems.

The Third IFIP International Working Conference on Dependable Computing for Critical Applications, like its predecessors, addressed various aspects of computer system dependability, a broad term defined as the degree of trust that may justifiably be placed in a system's reliability, availability, safety, security, and performance.

The International Working Conference on Dependable Computing for Critical Applications was the first conference organized by IFIP Working Group 10. 4 "Dependable Computing and Fault Tolerance", in cooperation with the Technical Committee on Fault-Tolerant Computing of the IEEE Computer Society, and the Technical Committee 7 on Systems Reliability, Safety and Security of EWlCS. The rationale for the Working Conference is best expressed by the aims of WG 10. 4: " Increasingly, individuals and organizations are developing or procuring sophisticated computing systems on whose services they need to place great reliance. In differing circumstances, the focus will be on differing properties of such services - e. g. continuity, performance, real-time response, ability to avoid catastrophic failures, prevention of deliberate privacy intrusions. The notion of dependability, defined as that property of a computing system which allows reliance to be justifiably placed on the service it delivers, enables these various concerns to be subsumed within a single conceptual framework. Dependability thus includes as special cases such attributes as reliability, availability, safety, security. The Working Group is aimed at identifying and integrating approaches, methods and techniques for specifying, designing, building, assessing, validating, operating and maintaining computer systems which should exhibit some or all of these attributes. " The concept of WG 10. 4 was formulated during the IFIP Working Conference on Reliable Computing and Fault Tolerance on September 27-29, 1979 in London, England, held in conjunction with the Europ-IFIP 79 Conference. Profs A. Avi~ienis (UCLA, Los Angeles, USA) and A.