Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from View the MathML source and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics

Total order broadcast and multicast (also called atomic broadcast/multicast) present an important problem in distributed systems, especially with respect to fault-tolerance. In short, the primitive ensures that messages sent to a set of processes are, in turn, delivered by all those processes in the same total order. The problem has inspired an abundance of literature, with a plethora of proposed algorithms. This article proposes a classification of total order broadcast and multicast algorithms based on their ordering mechanisms, and addresses a number of other important issues. The article surveys about sixty algorithms, thus providing by far the most extensive study of the problem so far. The article discusses algorithms for both the synchronous and the asynchronous system models, and studies the respective properties and behavior of the different algorithms.X. Défago et al.

Designing, tuning, and analyzing the performance of distributed algorithms and protocols are complex tasks. A major factor that contributes to this complexity is the fact that there is no single environment to support all phases of the development of a distributed algorithm. This paper presents Neko, an easy-to-use Java platform that provides a uniform and extensible environment for various phases of algorithm design and performance evaluation: prototyping, tuning, simulation, deployment, etc.

Agreement problems, such as consensus, atomic broadcast, and group membership, are central to the implementation of fault-tolerant distributed systems. Despite the diversity of algorithms that have been proposed for solving agreement problems in the past years, almost all solutions are Crash-Detection Based (CDB ). We say that an algorithm is CDB if it uses some information about the status crashed /not crashed of processes. In this paper, we revisit the issue of non-CDB algorithms considering ordering oracles. Ordering oracles have a theoretical interest as well as a practical interest. To illustrate their use, we present solutions to consensus and atomic broadcast, and evaluate the performance of the atomic broadcast algorithm in a cluster of workstations.

Many atomic broadcast algorithms have been published in the last twenty years. Token-based algorithms represent a large class of these algorithms. Interestingly, all the token-based atomic broadcast algorithms rely on a group membership service, i.e., none of them uses unreliable failure detectors directly. The paper presents the first token-based atomic broadcast algorithm that uses an unreliable failure detector -the new failure detector denoted by R -instead of a group membership service. The failure detector R is compared with ♦P and ♦S. In order to make it easier to understand the atomic broadcast algorithm, the paper derives the atomic broadcast algorithm from a token-based consensus algorithm that also uses the failure detector R.