the goal of the paper is to describe run time efficiency of distributed computing environments. Six tools: PVM, P4, ANSA, SR, Strand, and Linda were chosen and investigated because they represent different approaches ...
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the goal of the paper is to describe run time efficiency of distributed computing environments. Six tools: PVM, P4, ANSA, SR, Strand, and Linda were chosen and investigated because they represent different approaches to distributed programming systems construction. the experimental results of communication tests and processor farm model efficiency are presented and discussed.< >
Presents a new algorithm for distributed shared virtual memory dedicated to diskless embedded systems. In this context, we adapt an existing algorithm in order to include a page replacement mechanism. We also propose ...
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Presents a new algorithm for distributed shared virtual memory dedicated to diskless embedded systems. In this context, we adapt an existing algorithm in order to include a page replacement mechanism. We also propose a memory partition to optimize memory space use. In conclusion, our algorithm has a complexity comparable withthe initial one.< >
the media streams of a multimedia communication application may traverse through different communication channels. Because of the network delay and jitter, data in these streams sent at the same time may not arrive at...
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the media streams of a multimedia communication application may traverse through different communication channels. Because of the network delay and jitter, data in these streams sent at the same time may not arrive at a destination simultaneously. In this paper a multimedia synchronization protocol that resynchronizes the media streams is proposed. the protocol inserts extra control cells into the media streams, and aligns the cells at the receiver site. three synchronization policies, namely, the Drop-Old, the Transmit-Old and the Delayed-Transmit, are introduced to align the control cells. To satisfy the Quality of Service (QOS) specified by an application, the protocol must negotiate an appropriate QOS withthe underlying ATM network. For each of the three synchronization policies, the relationship between the specified QOS and the negotiated QOS is derived.< >
SPIDER is a network adapter that provides scalable communication support for point-to-point distributed systems. the device exports an efficient interface to the host processor, provides transparent support for depend...
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SPIDER is a network adapter that provides scalable communication support for point-to-point distributed systems. the device exports an efficient interface to the host processor, provides transparent support for dependable, time-constrained communication, and handles packet routing and switching. the communication support provided by SPIDER exploits concurrency between the independent data channels feeding the point-to-point network, and offers flexible and transparent hardware mechanisms. SPIDER allows the host to exercise fine-grain control over its operation, enabling the latter to monitor and influence data transmission and reception efficiently. In the current implementation, SPIDER interfaces to the Ironics IV-3207, a VMEbus-based 68040 card and will be controlled by x-kernel, a communication executive allowing the flexible composition of communication protocols.< >
this paper is concerned withthe problem of communicating abstract data type (ADT) values in heterogeneous distributed programs. It focuses on addressing two fundamental issues of the problem: the selection of suitabl...
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this paper is concerned withthe problem of communicating abstract data type (ADT) values in heterogeneous distributed programs. It focuses on addressing two fundamental issues of the problem: the selection of suitable exchange representations and the generation of data converters. Exchange representations are the ways to represent data during transmissions across networks. Data converters are programs transforming data from one representation to another; they are the major facility to deal with heterogeneity in a communication. this paper reports the following results: a term-based exchange representation, which is an abstract notation and so is particularly suitable for communicating ADT values in heterogeneous programs; and methods to generate data converters.< >
this paper presents algorithms for distributed coin tossing. Distributed coin tossing furnishes a symmetrical way to break the symmetry in a distributed system. they allow the conflicts arising from competing remote s...
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this paper presents algorithms for distributed coin tossing. Distributed coin tossing furnishes a symmetrical way to break the symmetry in a distributed system. they allow the conflicts arising from competing remote sites to be overcome in a fair (equiprobable) manner: any site has an equal chance of being selected. It as also shown how these algorithms may be used to obtain a total order between competing sites of a system. Moreover, in each case the outputs of our algorithms are totally unpredictable.< >
the distributed applications require group communications among multiple entities. In the group communication, it is important to discuss in what order each entity in the group can receive data units. In order to real...
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the distributed applications require group communications among multiple entities. In the group communication, it is important to discuss in what order each entity in the group can receive data units. In order to realize fault-tolerant systems, the same events have to occur in the same order in each entity. the ordering among the events is known as a causal order. this paper presents a reliable causally ordering broadcast (CO) protocol which provides the same causal ordering of data units for all the entities in the group. In the CO protocol, the data units received are causally ordered by using the sequence numbers of the data units. the CO protocol is based on the fully distributed control scheme, i.e. no master controller, and uses high-speed networks where each entity may fail to receive data units due to the buffer overrun. Furthermore, the CO protocol provides asynchronous data transmission for multiple entities in the group.< >
Simple diffusion consists in propagating some data or computation to every unit in a network by spreading it from one unit to its neighbors, which in their turn spread it to the neighbors until every unit is reached. ...
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Simple diffusion consists in propagating some data or computation to every unit in a network by spreading it from one unit to its neighbors, which in their turn spread it to the neighbors until every unit is reached. Simple diffusion is easy to implement, scalable, robust with respect to omission faults, and privileges local communication (i.e., uses only links whose cost is the lowest in terms of time needed and/or traffic generated). A solution to the problem of keeping synchronized all the clocks in a large distributed system is presented, that is based on simple diffusion. the traffic generated is O(N), where N is the number of units in the network. the attainable precision is O(d*/spl epsiv/) where /spl epsiv/ is the precision with which a unit can synchronize its clock withthat of a neighbor, and d is the maximum distance between a unit and the nearest reference clock.< >
We formulate a model of extended virtual synchrony that defines a group communication transport service for multicast and broadcast communication in a distributed system. the model extends the virtual synchrony model ...
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We formulate a model of extended virtual synchrony that defines a group communication transport service for multicast and broadcast communication in a distributed system. the model extends the virtual synchrony model of the Isis system to support continued operation in all components of a partitioned network. the significance of extended virtual synchrony is that, during network partitioning and remerging and during process failure and recovery, it maintains a consistent relationship between the delivery of messages and the delivery of configuration changes across all processes in the system and provides well-defined self-delivery and failure atomicity properties. We describe an algorithm that implements extended virtual synchrony and construct a filter that reduces extended virtual synchrony to virtual synchrony.< >
Distributed algorithms have hitherto been designed for networks with static hosts. A mobile host (MH) can connect to the network from different locations at different times. this paper presents an operational system m...
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Distributed algorithms have hitherto been designed for networks with static hosts. A mobile host (MH) can connect to the network from different locations at different times. this paper presents an operational system model for explicitly incorporating the effects of host mobility and proposes a general principle for structuring efficient distributed algorithms in this model. this principle is used to redesign two classical algorithms for distributed mutual exclusion for the mobile environment. We then consider a problem introduced solely by host mobility viz, location management for groups of MHs, and propose the concept of group location as an efficient approach to tackle the problem. Lastly, we present a framework which enables host mobility to be decoupled from the design of a distributed algorithm per se, to varying degrees.< >
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