the authors present the design and implementation of an asynchronous remote operation execution facility, futures, that retains the benefits of the remote procedure call (RPC) abstraction but allows execution to proce...
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the authors present the design and implementation of an asynchronous remote operation execution facility, futures, that retains the benefits of the remote procedure call (RPC) abstraction but allows execution to proceed locally in parallel with remote execution and provides extensive support for managing replies. It is shown how this facility can be easily used to support many common interprocess communication styles, including RPC, multicast, broadcast, returning incremental results, and the multiplexing of multiple remote computations. A flow control mechanism for futures is described.< >
CODOSO, a combinative distributed operating system family that serves as an integrated environment for building various distributed operating systems according to different application requirements, is discussed. the ...
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CODOSO, a combinative distributed operating system family that serves as an integrated environment for building various distributed operating systems according to different application requirements, is discussed. the basis of the CODOSO project is CLUSTER 86, an object-oriented programming languages. CODOSO is designed in an object model based on the language, in which the entire system is implemented. the authors discuss how the CODOSO distributedcomputing models are built up through CLUSTER 86. they outline the design philosophy and the implementation strategy, and present a brief comparison with some other related work.< >
the problems of building a distributed shared memory system on a network of heterogeneous machines are discussed. An existing algorithm (due to K. Li, 1986) that implements distributed shared memory is extended to a h...
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the problems of building a distributed shared memory system on a network of heterogeneous machines are discussed. An existing algorithm (due to K. Li, 1986) that implements distributed shared memory is extended to a heterogeneous environment. An implementation that runs on Sun and DEC Firefly multiprocessor workstations connected by Ethernet is described. Related implementation and performance issues are discussed. On the basis of measurements of the applications ported to the system, it is concluded that heterogeneous distributed shared memory is not only feasible but can also be compared in performance to its homogeneous counterpart.< >
Requirements for distributed processing of multimedia information are summarized and compared with recent efforts at standardization. An approach toward an integrated information and communication model, which can be ...
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Requirements for distributed processing of multimedia information are summarized and compared with recent efforts at standardization. An approach toward an integrated information and communication model, which can be viewed as a special form of a model for open distributed applications, is outlined. Additionally, synchronization aspects of isochronous and anisochronous communication are outlined. the model is still under development. Especially in the areas of modeling individual information types and communication protocols, more detailed work needs to be done.< >
the authors present a revolving hierarchical scheme in which the logical position of a process in the hierarchy changes with time so that the reorganization of hierarchy is achieved concurrently with its use. the tech...
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the authors present a revolving hierarchical scheme in which the logical position of a process in the hierarchy changes with time so that the reorganization of hierarchy is achieved concurrently with its use. the technique is useful for repeated computation of global functions that require information from all processes. It results in algorithms that are not only fair to all nodes, but also less expensive in terms of messages. the reduction in the number of messages is achieved by reusing messages for more than one computation of the global function. the technique is illustrated for hierarchical snapshot computation and distributed branch-and-bound problems.< >
A constructive design approach to distributed systems is described. the approach is illustrated by a model airport shuttle system, which is implemented in an environment for distributed programming called Conic. the m...
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A constructive design approach to distributed systems is described. the approach is illustrated by a model airport shuttle system, which is implemented in an environment for distributed programming called Conic. the main principles on which the constructive approach is based are those of explicit system structure and context-independent components. Structure is explicitly described and preserved during the software development process, from initial design to actual system construction and evolution. thus the main structural design information is retained in the constructed system itself. the second principle that of context independence of components, reduces the design and implementation effort by facilitating early identification of component types and component interface specifications.< >
the authors describe a way of noticeably reducing the description cost of database operations executed in distributedcomputing environments through the design of a declarative language to describe database operations...
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the authors describe a way of noticeably reducing the description cost of database operations executed in distributedcomputing environments through the design of a declarative language to describe database operations, the development of program transformation techniques to improve efficiency at execution time, and the clarification of prerequisites to execute the programs in distributedcomputing environments. Withthe language, database operations are described as functions which manipulate streams. To describe stream manipulation at a higher level, the language SPL (Set Programming Language) is based on mathematical comprehensive notation for sets (ZF expressions). Withthis language, database operation implementors need not specify any communication primitives; a language processing system automatically translates the programs into procedural programs which include communication primitives.< >
the problem of finding an optimal assignment of task modules with a precedence relationship in a distributedcomputing system is considered. the objective of task assignment is to minimize the task turnaround time. th...
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the problem of finding an optimal assignment of task modules with a precedence relationship in a distributedcomputing system is considered. the objective of task assignment is to minimize the task turnaround time. the problem is known to be NP-complete for more than three processors. To solve the problem, a well-known state-space reduction technique, branch-and-bound-with-underestimates, is applied, and two underestimate functions are defined. through experiments, their effectiveness is shown by comparing the proposed algorithm with both Wang and Tsai's (1988) algorithm and the A* algorithm with h(x)=0.< >
An extension of the uniprocessor Hartstone benchmark for the distributed real-time environment, called the distributed Hartstone benchmark, is described. the distributed Hartstone measures system performance in the cr...
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An extension of the uniprocessor Hartstone benchmark for the distributed real-time environment, called the distributed Hartstone benchmark, is described. the distributed Hartstone measures system performance in the critical areas of communication latency and bandwidth, protocol preemptability, and priority queueing at the protocol and media access levels. Areas of the system which are particularly important for distributed, real-time computing are described. On the basis of the requirements that specify various areas of the system that a distributed real-time benchmark must stress, a series of task sets in the style of the Hartstone benchmarks are given. the benchmark results from a distributed real-time operating system (ARTS testbed) are given.< >
Various approaches to the problem of replay detection in distributed systems are briefly reviewed. An approach based on combining a variable-size time-window mechanism with a challenge mechanism is proposed. this appr...
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Various approaches to the problem of replay detection in distributed systems are briefly reviewed. An approach based on combining a variable-size time-window mechanism with a challenge mechanism is proposed. this approach has the following properties: (1) it does not depend on clock synchronization, (2) it allows the setting of a minimum server's memory-buffer size in a way that ensures acceptance of all legitimate client requests and (3) it is robust without requiring stable (nonvolatile) memory for the server buffer needed to save past client requests.< >
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