This book presents the most important fault-tolerant distributed programming abstractions and their associated distributed algorithms, in particular in terms of reliable communication and agreement, which lie at the heart of nearly all distributed applications. These programming abstractions, distributed objects or services, allow software designers and programmers to cope with asynchrony and the most important types of failures such as process crashes, message losses, and malicious behaviors of computing entities, widely known under the term "Byzantine fault-tolerance". The author introduces these notions in an incremental manner, starting from a clear specification, followed by algorithms which are first described intuitively and then proved correct. The book also presents impossibility results in classic distributed computing models, along with strategies, mainly failure detectors and randomization, that allow us to enrich these models. In this sense, the book constitutes an introduction to the science of distributed computing, with applications in all domains of distributed systems, such as cloud computing and blockchains. Each chapter comes with exercises and bibliographic notes to help the reader approach, understand, and master the fascinating field of fault-tolerant distributed computing.

This book presents the most important fault-tolerant distributed programming abstractions and their associated distributed algorithms, in particular in terms of reliable communication and agreement, which lie at the heart of nearly all distributed applications. These programming abstractions, distributed objects or services, allow software designers and programmers to cope with asynchrony and the most important types of failures such as process crashes, message losses, and malicious behaviors of computing entities, widely known under the term "Byzantine fault-tolerance". The author introduces these notions in an incremental manner, starting from a clear specification, followed by algorithms which are first described intuitively and then proved correct. The book also presents impossibility results in classic distributed computing models, along with strategies, mainly failure detectors and randomization, that allow us to enrich these models. In this sense, the book constitutes an introduction to the science of distributed computing, with applications in all domains of distributed systems, such as cloud computing and blockchains. Each chapter comes with exercises and bibliographic notes to help the reader approach, understand, and master the fascinating field of fault-tolerant distributed computing.

Understanding distributed computing is not an easy task. This is due to the many facets of uncertainty one has to cope with and master in order to produce correct distributed software. A previous book Communication and Agreement Abstraction for Fault-tolerant Asynchronous Distributed Systems (published by Morgan & Claypool, 2010) was devoted to the problems created by crash failures in asynchronous message-passing systems. The present book focuses on the way to cope with the uncertainty created by process failures (crash, omission failures and Byzantine behavior) in synchronous message-passing systems (i.e., systems whose progress is governed by the passage of time). To that end, the book considers fundamental problems that distributed synchronous processes have to solve. These fundamental problems concern agreement among processes (if processes are unable to agree in one way or another in presence of failures, no non-trivial problem can be solved). They are consensus, interactive consistency, k-set agreement and non-blocking atomic commit. Being able to solve these basic problems efficiently with provable guarantees allows applications designers to give a precise meaning to the words ""cooperate"" and ""agree"" despite failures, and write distributed synchronous programs with properties that can be stated and proved. Hence, the aim of the book is to present a comprehensive view of agreement problems, algorithms that solve them and associated computability bounds in synchronous message-passing distributed systems. Table of Contents: List of Figures / Synchronous Model, Failure Models, and Agreement Problems / Consensus and Interactive Consistency in the Crash Failure Model / Expedite Decision in the Crash Failure Model / Simultaneous Consensus Despite Crash Failures / From Consensus to k-Set Agreement / Non-Blocking Atomic Commit in Presence of Crash Failures / k-Set Agreement Despite Omission Failures / Consensus Despite Byzantine Failures / Byzantine Consensus in Enriched Models

Lecture Series on Computer and on Computational Sciences (LSCCS) aims to provide a medium for the publication of new results and developments of high-level research and education in the field of computer and computational science.In this series, only selected proceedings of conferences in all areas of computer science and computational sciences wil

The most important use of computing in the future will be in the context of the global "digital convergence" where everything becomes digital and every thing is inter-networked. The application will be dominated by storage, search, retrieval, analysis, exchange and updating of information in a wide variety of forms. Heavy demands will be placed on systems by many simultaneous re quests. And, fundamentally, all this shall be delivered at much higher levels of dependability, integrity and security. Increasingly, large parallel computing systems and networks are providing unique challenges to industry and academia in dependable computing, espe cially because of the higher failure rates intrinsic to these systems. The chal lenge in the last part of this decade is to build a systems that is both inexpensive and highly available. A machine cluster built of commodity hardware parts, with each node run ning an OS instance and a set of applications extended to be fault resilient can satisfy the new stringent high-availability requirements. The focus of this book is to present recent techniques and methods for im plementing fault-tolerant parallel and distributed computing systems. Section I, Fault-Tolerant Protocols, considers basic techniques for achieving fault-tolerance in communication protocols for distributed systems, including synchronous and asynchronous group communication, static total causal order ing protocols, and fail-aware datagram service that supports communications by time.

Themessagepassingparadigmisconsideredthemoste?ectivewaytodevelop- ?cient parallel applications. PVM (Parallel Virtual Machine) and MPI (Message Passing Interface) are the most frequently used tools for programming message passing applications. This volume includes the selected contributions presented at the 10th - ropean PVM/MPI Users’ Group Meeting (Euro PVM/MPI 2003), which was held in Venice, Italy, September 29–October 2, 2003. The conference was jointly organized by the Department of Computer Science of the Ca’ Foscari University of Venice, Italy and the Information Science and Technologies Institute of the National Research Council (ISTI-CNR), Pisa, Italy. TheconferencewaspreviouslyheldinLinz,Austria(2002),Santorini,Greece (2001), Balatonfured, ̈ Hungary (2000), Barcelona, Spain (1999), Liverpool, UK (1998), and Krakow, Poland (1997). The ?rst three conferences were devoted to PVM and were held in Munich, Germany (1996), Lyon, France (1995), and Rome, Italy (1994). The conference has become a forum for users and developers of PVM, MPI, and other message passing environments. Interactions between these groups has proved to be very useful for developing new ideas in parallel computing, and for applying some of those already existent to new practical ?elds. The main topics of the meeting were evaluation and performance of PVM and MPI, ext- sions, implementations and improvements of PVM and MPI, parallel algorithms using the message passing paradigm, and parallel applications in science and engineering. In addition, the topics of the conference were extended to include Grid computing, in order to re?ect the importance of this area for the hi- performance computing community.

As the structure of contemporary communication networks grows more complex, practical networked distributed systems become prone to component failures. Fault-tolerant consensus in message-passing systems allows participants in the system to agree on a common value despite the malfunction or misbehavior of some components. It is a task of fundamental importance for distributed computing, due to its numerous applications. We summarize studies on the topological conditions that determine the feasibility of consensus, mainly focusing on directed networks and the case of restricted topology knowledge at each participant. Recently, significant efforts have been devoted to fully characterize the underlying communication networks in which variations of fault-tolerant consensus can be achieved. Although the deduction of analogous topological conditions for undirected networks of known topology had shortly followed the introduction of the problem, their extension to the directed network case has been proven a highly non-trivial task. Moreover, global knowledge restrictions, inherent in modern large-scale networks, require more elaborate arguments concerning the locality of distributed computations. In this work, we present the techniques and ideas used to resolve these issues. Recent studies indicate a number of parameters that affect the topological conditions under which consensus can be achieved, namely, the fault model, the degree of system synchrony (synchronous vs. asynchronous), the type of agreement (exact vs. approximate), the level of topology knowledge, and the algorithm class used (general vs. iterative). We outline the feasibility and impossibility results for various combinations of the above parameters, extensively illustrating the relation between network topology and consensus.

Timo Warns has developed tractable fault models that, while being non-probabilistic, are accurate for dependent and propagating faults. Using seminal problems such as consensus and constructing coteries, he demonstrates how the new models can be used to design and evaluate effective and efficient means of fault tolerance.

This book constitutes the proceedings of 25th International Symposium, SSS 2023, in Jersey City, NJ, USA, in October 2023. The 32 full papers presented together with 8 short papers were carefully reviewed and selected from 78 submissions. The conference was organized into five tracks reflecting major trends related to the conference: (i) Track A. Self-stabilizing Systems: Theory and Practice, (ii) Track B. Distributed and Concurrent Computing: Foundations, Fault-Tolerance and Scalability, (iii) Track C. Cryptogrophy and Security, (iv) Track D. Dynamic, Mobile and Nature-Inspired Computing Mobile Agents, (v) and Distributed Databases.

This practical new book offers the distributed-computing fundamental knowledge for individuals to connect with one another in a more secure and efficient way than with traditional blockchains. These new forms of secure, scalable blockchains promise to replace centralized institutions to connect individuals without the risks of user manipulations or data extortions. The techniques taught herein consist of enhancing blockchain security and making blockchain scalable by relying on the observation that no blockchain can exist without solving the consensus problem. First, the state-of-the-art of consensus protocols are analyzed, hence motivating the need for a new family of consensus protocols offering strong (deterministic) guarantees. Second, a didactic series of classic blockchain vulnerabilities is presented to illustrate the importance of novel designs better suited for the adversarial environment of open networks. These cutting-edge solutions are illustrated through the Redbelly blockchain design, which solves a different problem from the classic Byzantine consensus problem of 1982 and which delivers—in the modern blockchain context—high performance at large scale. Topics and features: Covers the combination of security and distributed computing to devise the new generation of blockchains Shows how blockchain has shed new light on decades of research in distributed systems Provides instruction on the security needed by the industry to use blockchains in production Explains didactically the necessary ingredients to make blockchain efficient at large scale Helps fill the gap of knowledge in the highly demanded blockchain sector This unique volume contains the building blocks to design secure and scalable blockchains. As such, it is dedicated to developers, application designers, and computer scientists and requires only a minimal undergraduate level in mathematics and computer science. Vincent Gramoli is an Australian Research Council Future Fellow at the University of Sydney and the Chief Technology Officer of Redbelly Network. He teaches the Blockchain Scalability course on Coursera.