Key Research Pointers Shifting the focus from software reliability to user-centred measures of dependability in complete software-based systems. Influencing design practice to facilitate dependability assessment. Propagating awareness of dependability issues and the use of existing, useful methods. Injecting some rigour in the use of process-related evidence for dependability assessment. Better understanding issues of diversity and variation as drivers of dependability. The Authors Bev

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... d is founder-Director of the Centre for Software Reliability, and Professor of Software Engineering at City University, London. Prof Littlewood has worked for many years on problems associated with the modelling and evaluation of the dependability of software-based systems; he has published many papers in international journals and conference proceedings and has edited several books. Much of this work has been carried out in collaborative projects, including the successful EC-funded projects SHIP, PDCS, PDCS2, DeVa. (1980). His research has addressed fault-tolerance in multiprocessor and distributed systems, protocols for high-speed networks, software fault tolerance via design diversity, software testing and software reliability assessment. He has been a principal investigator in several national and collaborative European research projects on these topics, and a consultant to industry on fault-tolerance and on reliability assurance for critical applications. He has published more than 60 papers in international journals and conferences. His main current interest is defining practical, rigorous methods for assessing the dependability of software and other systems subject to design faults, and for supporting development decisions to achieve it. He is a member of the IFIP Working Group 10.4 on Dependable Computing and Fault Tolerance, of IEEE and ACM and of the Editorial Board of the IEEE Transactions on Software Engineering. ABSTRACT Software's increasing role creates both requirements for being able to trust it more than before, and for more people to know how much they can trust their software. A sound engineering approach requires both techniques for producing reliability and sound assessment of the achieved results. Different parts of industry and society face different challenges: the need for education and cultural changes in some areas, the adaptation of known scientific results to practical use in others, and in others still the need to confront inherently hard problems of prediction and decision-making, both to clarify the limits of current understanding and to push them back. We outline the specific difficulties in applying a sound engineering approach to software reliability engineering, some of the current trends and problems and a set of issues that we therefore see as important in an agenda for research in software dependability.