Modern distributed storage systems are emerging as the primary choice for storing massive amounts of critical data that we generate today. A central goal of these systems is to ensure data durability, i.e., these systems must keep user data safe under all scenarios. To achieve high levels of durability, most modern systems store redundant copies of data on many machines. When a client wishes to update the data, the distributed system takes a set of actions to update these redundant copies, which we refer to as the system's durability model. At one end of the durability model spectrum, data is immediately replicated and persisted on many or all servers. While this immediate durability model offers strong guarantees, it suffers from poor performance. At the other end, data is only lazily replicated and persisted, eventually making it durable; this approach provides excellent performance but poor durability guarantees. The choice of durability model also influences what consistency models can be realized by the system. While immediate durability enables strong consistency, only weaker models can be realized upon eventual durability. Thus, in this dissertation, we seek to answer the following question: is it possible for a durability model to enable strong consistency guarantees, yet also deliver high performance? In the first part of this dissertation, we study the behavior of eight popular modern distributed systems and analyze whether they ensure data durability when the storage devices on the replicas fail partially, i.e., sometimes return corrupted data or errors. Our study reveals that redundancy does not provide fault tolerance; a single storage fault can result in catastrophic outcomes such as user-visible data loss, unavailability, and spread of corruption. In the second part, to address the fundamental tradeoff between consistency and performance, we propose consistency-aware durability or CAD, a new way to achieving durability in distributed systems. The key idea behind CAD is to shift the point of durability from writes to reads. By delaying durability upon writes, CAD provides high performance; however, by ensuring the durability of data before serving reads, CAD enables the construction of strong consistency models. Finally, we introduce cross-client monotonic reads, a novel and strong consistency property that provides monotonic reads across failures and sessions. We show that this property can be efficiently realized upon CAD, while other durability models cannot enable this property with high performance. We also demonstrate the benefits of this new consistency model.

A unifying foundation to design and implement process-aware information systems This publication takes on the formidable task of establishing a unifying foundation and set of common underlying principles to effectively model, design, and implement process-aware information systems. Authored by leading authorities and pioneers in the field, Process-Aware Information Systems helps readers gain a thorough understanding of major concepts, languages, and techniques for building process-aware applications, including: * UML and EPCs: two of the most widely used notations for business process modeling * Concrete techniques for process design and analysis * Process execution standards: WfMC and BPEL * Representative commercial tools: ARIS, TIBCO Staffware, and FLOWer Each chapter begins with a description of the problem domain and then progressively unveils relevant concepts and techniques. Examples and illustrations are used extensively to clarify and simplify complex material. Each chapter ends with a set of exercises, ranging from simple questions to thought-provoking assignments. Sample solutions for many of the exercises are available on the companion Web site. Armed with a new and deeper understanding, readers are better positioned to make their own contributions to the field and evaluate various approaches to a particular task or problem. This publication is recommended as a textbook for graduate and advanced undergraduate students in computer science and information systems, as well as for professionals involved in workflow and business process management, groupware and teamwork, enterprise application integration, and business-to-business integration. A Solution's Manual is available online. An Instructor Support FTP site is also available.

Programming WCF Services is the authoritative, bestselling guide to Microsoft's unified platform for developing modern service-oriented applications on Windows. Hailed as the definitive treatment of WCF, this book provides unique insight, rather than documentation, to help you learn the topics and skills you need for building WCF-based applications that are maintainable, extensible, and reusable. Author Juval Löwy -- one of the world's top .NET experts -- revised this edition to include the newest productivity-enhancing features of .NET Framework 4 and the Azure AppFabric Service Bus, as well as the latest WCF ideas and techniques. By teaching you the why and the how of WCF programming, Programming WCF Services will help you master WCF and make you a better software engineer. Learn about WCF architecture and essential building blocks, including key concepts such as reliability and transport sessions Use built-in features such as service hosting, instance and concurrency management, transactions, disconnected queued calls, security, and discovery Master the Windows Azure AppFabric Service Bus, the most revolutionary piece of the new cloud computing initiative Increase your productivity and the quality of your WCF services by taking advantage of relevant design options, tips, and best practices in Löwy's ServiceModelEx framework Discover the rationale behind particular design decisions, and delve into rarely understood aspects of WCF development "If you choose to learn WCF, you've chosen well. If you choose to learn with the resource and guidance of Juval Löwy, you've done even better... there are few people alive today who know WCF as well." --Ron Jacobs, Senior Technical Evangelist for WCF, Microsoft Corporation

In Secrets of Greatness, Dr Burrell provides us with a route map to success of the very highest order, consistent with the greatest model of success known to us, Jesus Christ. Based upon an intimate study of the Old and New Testaments, and a lifetime’s work as a pastor, and drawing together such disparate threads as psychology, biology, history and motivational dynamics, Dr Burrell gives his readers a meticulous and definitive explanation of the essence of greatness and how it is within the capability of each and every one of us to achieve more than we ever thought possible. A thorough and passionate exploration of what it means to be great, using examples of great men and women through the ages, Secrets of Greatness decries the notion that true success lies in power, money and status, and illustrates instead that the pinnacle of human achievement is attainable only through the transformative and healing power of our relationship with God. In each chapter and section, the author shines a light on a different aspect of the process of becoming what we are destined to be in the Creator’s great plan for us, and illuminates the spaces through which we all must travel on our journey to greatness. Dr Burrell explores his subject with the keen mind of a scholar, the compassion of a man of God and the tenacity of a warrior, and has written a book which is as uplifting as it is useful. It is a book which can only fill us with hope for the future. Secrets of Greatness is a corrective for our secular age – a spiritual book in materialistic times - and a tonic for all those who thirst for a different measure of success than is commonly presented in our media.

Cloud storage services and NoSQL systems typically offer only "Eventual Consistency", a rather weak guarantee covering a broad range of potential data consistency behavior. The degree of actual (in-)consistency, however, is unknown. This work presents novel solutions for determining the degree of (in-)consistency via simulation and benchmarking, as well as the necessary means to resolve inconsistencies leveraging this information.

This book comprehensively illustrates quality-ware scheduling in key-value stores. In addition, it provides scheduling strategies and a prototype framework of quality-aware scheduler as well as a demonstration of online applications. The book offers a rich blend of theory and practice which is suitable for students, researchers and practitioners interested in distributed systems, NoSQL key-value stores and scheduling.