...Life, Death, and the Critical Transition: Finding Liveness Bugs in Systems Code Charles Killian, James W. Anderson, Ranjit Jhala, and Amin Vahdat University of California San Diego {ckillian,jwanderson,jhala,vahdat}@cs.ucsd.edu Abstract finding bugs with model checking currently requires the programmer to have intimate knowledge of the low-level Modern software model checkers find safety violations: actions or conditions that could result in system failure. breaches where the system has entered some bad state. For We contend that for complex systems the desirable bemany environments however, particularly complex con- haviors of the system may be specified more easily than current and distributed systems, we argue that liveness identifying everything that could go wrong. Of course, properties are both more natural to specify and more im- specifying both desirable conditions and safety assertions portant to check. Liveness conditions specify desirable is valuable; however, current model checkers do not have system conditions in the limit, with the expectation that any mechanism for verifying whether desirable system they will be temporarily violated, perhaps as a result of properties can be achieved. Examples of such properties failure or during system initialization. include: i) a reliable transport eventually delivers all mesExisting software model checkers cannot verify live- sages even in the face of network losses and delays, ii) all ness because doing so...
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...Acknowledgments ix Acknowledgments This book owes a great deal to the mental energy of several generations of scholars. As an undergraduate at the University of Cape Town, Francis Wilson made me aware of the importance of migrant labour and Robin Hallett inspired me, and a generation of students, to study the African past. At the School of Oriental and African Studies in London I was fortunate enough to have David Birmingham as a thesis supervisor. I hope that some of his knowledge and understanding of Lusophone Africa has found its way into this book. I owe an equal debt to Shula Marks who, over the years, has provided me with criticism and inspiration. In the United States I learnt a great deal from ]eanne Penvenne, Marcia Wright and, especially, Leroy Vail. In Switzerland I benefitted from the friendship and assistance of Laurent Monier of the IUED in Geneva, Francois Iecquier of the University of Lausanne and Mariette Ouwerhand of the dépurtement évangélrlyue (the former Swiss Mission). In South Africa, Patricia Davison of the South African Museum introduced me to material culture and made me aware of the richness of difference; the late Monica Wilson taught me the fundamentals of anthropology and Andrew Spiegel and Robert Thornton struggled to keep me abreast of changes in the discipline; Sue Newton-King and Nigel Penn brought shafts of light from the eighteenthcentury to bear on early industrialism. Charles van Onselen laid a major part of the intellectual foundations on...
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