A description is given of a collection of tools that form an implementation of event-based abstraction (EBBA), a paradigm for high-level debugging of distributed systems. the tools are capable of operating effectively...
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ISBN:
(纸本)081860865X
A description is given of a collection of tools that form an implementation of event-based abstraction (EBBA), a paradigm for high-level debugging of distributed systems. the tools are capable of operating effectively in a heterogeneous environment containing processors of varying design and power. Toolset users construct libraries of behavior models and observe the behavior of the system through the models. the toolset is a collection of components that are collectively a distributed system for debugging distributed systems. the components can be combined in varying ways to provide levels of debugging service appropriate for the resources available as individual nodes.
the integration of accounting functions and an account server into the distributed academic computing network operating system (DACNOS), which is an NOS built on top of a heterogeneous collection of networked computer...
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ISBN:
(纸本)081860865X
the integration of accounting functions and an account server into the distributed academic computing network operating system (DACNOS), which is an NOS built on top of a heterogeneous collection of networked computers, is described. the accounting is supported by NOS-kernel mechanisms that can be tailored to the needs of the heterogeneous servers. Accounting data is collected and stored by an account server in the NOS that manages the balances and the resource consumption data of clients. Depending on privileges, accounting data is accessible to clients, servers, and an account server administrator who may use this information for various resource and request management purposes.
A logic-oriented object base is defined to be a deductive database based on an object data model. Like conventional databases, logic-oriented object bases can be constructed on top of computer networks in such a way t...
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ISBN:
(纸本)081860865X
A logic-oriented object base is defined to be a deductive database based on an object data model. Like conventional databases, logic-oriented object bases can be constructed on top of computer networks in such a way that the distribution of logical and physical components of the system is kept hidden from the users. Objects are organized hierarchically and are retrieved through customized methods. the problem of query optimization in such an environment is investigated.
Request-response communication is studied in the framework of the functional communication model. A scheme that uses the channel access algorithm for distributed scheduling is investigated. A timed token protocol is u...
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ISBN:
(纸本)081860865X
Request-response communication is studied in the framework of the functional communication model. A scheme that uses the channel access algorithm for distributed scheduling is investigated. A timed token protocol is used to control the two access modes, the scheduled access, with communication initiated by a server, and the nonscheduled access when a client sends a request to a functional group without prior consent from any of the servers in the group. In case of scheduled communication, the server guarantees the acceptance of the request.
In a hybrid distributed-centralized database system architecture, some transactions run at (geographically) distributed systems, and other transactions at a central computing complex. Static and dynamic load-sharing s...
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ISBN:
(纸本)081860865X
In a hybrid distributed-centralized database system architecture, some transactions run at (geographically) distributed systems, and other transactions at a central computing complex. Static and dynamic load-sharing strategies are studied for such systems. the strategies take into account not only the difference in load at different sites, but also the effect of routing on data-contention and transaction-abort probabilities. Five dynamic strategies are examined and are compared with an optimal static strategy. A dynamic strategy that is based on analytical estimates of the effect of routing on all transactions in the system, rather than that on the incoming transaction alone, is found to be the best.
A constrained expression approach to analyzing large-scale software is presented. Its advantages include broad applicability and reasonable efficiency relative to other proposed approaches. An overview is given of the...
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ISBN:
(纸本)081860865X
A constrained expression approach to analyzing large-scale software is presented. Its advantages include broad applicability and reasonable efficiency relative to other proposed approaches. An overview is given of the current status of work on tools supporting analysis of distributed software systems. the constrained expression approach is outlined, and it is shown how it can be used to analyze distributed software. this is illustrated by a description of a recent experiment. An improved prototype toolset currently being built is described. Plans for enhanced tools and further experimentation are summarized.
the design and performance of scheduling facilities for finding idle hosts in a workstation-based distributed system are described. the focus is on the tradeoffs between centralized and decentralized architectures wit...
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ISBN:
(纸本)081860865X
the design and performance of scheduling facilities for finding idle hosts in a workstation-based distributed system are described. the focus is on the tradeoffs between centralized and decentralized architectures with respect to scalability, fault tolerance, and simplicity of design, as well as several implementation issues of interest when using multicast communication. It is concluded that the principal tradeoff between the two approaches is that a centralized architecture can be scaled to a significantly greater degree and can more easily monitor global system statistics, while a decentralized architecture is simpler to implement.
Running simulations in a distributed manner by decentralizing the advancement of clock potentially allows significant speedup. However, because time may not advance at the same rate in the target system and the testbe...
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ISBN:
(纸本)081860865X
Running simulations in a distributed manner by decentralizing the advancement of clock potentially allows significant speedup. However, because time may not advance at the same rate in the target system and the testbed system, deadlocks that do not occur in the target system can occur during distributed simulation. Previous approaches to deadlock resolution incur either high computation overhead through centralized coordination or high communication overhead through a fully distributed solution. Hierarchical decentralized algorithms that take advantage of the locality of these deadlocks are presented. Overheads associated with time advancement are computed analytically, so that appropriate clustering policies can be designed.
Interactive debugging requires that the programmer be able to halt a program at interesting points in its execution. the authors define distributed breakpoints and present an algorithm for implementing the detection p...
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ISBN:
(纸本)081860865X
Interactive debugging requires that the programmer be able to halt a program at interesting points in its execution. the authors define distributed breakpoints and present an algorithm for implementing the detection points and an algorithm for halting a distributed program in a consistent state. Events that can be partially ordered are defined as detectable and form the basis for the breakpoint predicates. From the breakpoint definition, an algorithm is obtained that can be used in a distributed debugger to detect these breakpoints. the halting algorithm extends K.M. Chandy and L. Lamport's (1985) algorithm for recording global state and solves the problem of processes that are not fully connected or frequently communicating.
A description is given of a novel concept and mechanism, called an object group, that realizes hierarchical, integrated object processing and management. Object groups can be used as a software basis for constructing ...
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ISBN:
(纸本)081860865X
A description is given of a novel concept and mechanism, called an object group, that realizes hierarchical, integrated object processing and management. Object groups can be used as a software basis for constructing object-based distributed systems. they support hierarchical control of objects, group-oriented communications, group access control, group resource management, and some generic operations on groups, providing consistent and uniform interfaces. Applications include job control, parallel processing, servers, object pools, hierarchical resource management, and so on. Some design issues are presented, and an implementation on a network-transparent global distributed system, which is under development, is discussed.
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