Distributed Computing 

About: Distributed Computing is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Drilling & Drilling fluid. It has an ISSN identifier of 0178-2770. Over the lifetime, 3797 publications have been published receiving 61742 citations. The journal is also known as: Distributed computing (Print).

Software transactional memory

Abstract: As we learn from the literature, flexibility in choosing synchronization operations greatly simplifies the task of designing highly concurrent programs. Unfortunately, existing hardware is inflexible and is at best on the level of a Load–Linked/Store–Conditional operation on a single word. Building on the hardware based transactional synchronization methodology of Herlihy and Moss, we offer software transactional memory (STM), a novel software method for supporting flexible transactional programming of synchronization operations. STM is non-blocking, and can be implemented on existing machines using only a Load–Linked/Store–Conditional operation. We use STM to provide a general highly concurrent method for translating sequential object implementations to non-blocking ones based on implementing a k-word compare&swap STM-transaction. Empirical evidence collected on simulated multiprocessor architectures shows that our method always outperforms the non-blocking translation methods in the style of Barnes, and outperforms Herlihy’s translation method for sufficiently large numbers of processors. The key to the efficiency of our software-transactional approach is that unlike Barnes style methods, it is not based on a costly “recursive helping” policy.

On interprocess communication: Part I: Basic formalism

Abstract: A formalism for specifying and reasoning about concurrent systems is described. Unlike more conventional formalisms, it is not based upon atomic actions. A definition of what it means for one system to implement a higher-level system is given and justified. In Part II, the formalism is used to specify several classes of interprocess communication mechanisms and to prove the correctness of algorithms for implementing them.

The Torus Routing Chip

Abstract: The torus routing chip (TRC) is a self-timed chip that performs deadlock-free cut-through routing in k-ary n-cube multiprocessor interconnection networks using a new method of deadlock avoidance called virtual channels. A prototype TRC with byte wide self-timed communication channels achieved on first silicon a throughput of 64Mbits/s in each dimension, about an order of magnitude better performance than the communication networks used by machines such as the Caltech Cosmic Cube or Intel iPSC. The latency of the cut-through routing of only 150ns per routing step largely eliminates message locality considerations in the concurrent programs for such machines. The design and testing of the TRC as a self-timed chip was no more difficult than it would have been for a synchronous chip.

Byzantine quorum systems

Abstract: Quorum systems are well-known tools for ensuring the consistency and availability of replicated data despite the benign failure of data repositories. In this paper we consider the arbitrary (Byzantine) failure of data repositories and present the first study of quorum system requirements and constructions that ensure data availability and consistency despite these failures. We also consider the load associated with our quorum systems, i.e., the minimal access probability of the busiest server. For services subject to arbitrary failures, we demonstrate quorum systems over n servers with a load of O(1/√n), thus meeting the lower bound on load for benignly fault-tolerant quorum systems. We explore several variations of our quorum systems and extend our constructions to cope with arbitrary client failures.

Computation in networks of passively mobile finite-state sensors

Abstract: The computational power of networks of small resource-limited mobile agents is explored. Two new models of computation based on pairwise interactions of finite-state agents in populations of finite but unbounded size are defined. With a fairness condition on interactions, the concept of stable computation of a function or predicate is defined. Protocols are given that stably compute any predicate in the class definable by formulas of Presburger arithmetic, which includes Boolean combinations of threshold-k, majority, and equivalence modulo m. All stably computable predicates are shown to be in NL. Assuming uniform random sampling of interacting pairs yields the model of conjugating automata. Any counter machine with O (1) counters of capacity O (n) can be simulated with high probability by a conjugating automaton in a population of size n. All predicates computable with high probability in this model are shown to be in P; they can also be computed by a randomized logspace machine in exponential time. Several open problems and promising future directions are discussed.