作者：
Leitner, GeraldColumbia Univ
Dep of Computer Science New York NY USA Columbia Univ Dep of Computer Science New York NY USA
Many distributed applications are structured as a set of client processes generating requests for service, and a set of server processes servicing these requests. The common form of interprocess communication (IPC) be...
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ISBN:
(纸本)0818605642
Many distributed applications are structured as a set of client processes generating requests for service, and a set of server processes servicing these requests. The common form of interprocess communication (IPC) between two single processes does not provide adequate support for robustness and throughput optimization. The author presents a stylized form of IPC between a group of client processes and a group of server processes. The choice of a particular server process to service a request is made dynamically at run-time. This dynamic task distribution provides the kernel support needed to make individual failures of server processes transparent and to optimize system performance through load leveling. The semantics of stylized IPC and the high-level protocol to implement it are described. Particular emphasis is placed on minimizing the performance overhead incurred by this mechanism.
This issue contains 11 selected conference papers. The topics covered include: fact-based analysis and design;translation of entity-relationship (ER) diagrams into relational structures;ER behavior modeling;ER algebra...
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This issue contains 11 selected conference papers. The topics covered include: fact-based analysis and design;translation of entity-relationship (ER) diagrams into relational structures;ER behavior modeling;ER algebra;computer-aided layout of ER diagrams;data administration support;dictionary systems.system development;a database-oriented tool generator;and reliability control for distributeddatabasesystems.
This conference proceedings contains 81 papers, with 7 papers in abstract form only. Discussed are: software tool, software engineering environment, databasesystems.with special attention to management and distribute...
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ISBN:
(纸本)0818605502
This conference proceedings contains 81 papers, with 7 papers in abstract form only. Discussed are: software tool, software engineering environment, databasesystems.with special attention to management and distributedsystems. concurrency control, quality through software engineering, distributed programming, high-level languages, various design techniques, life cycles, softwarereliability and reusability, national standards and standardization efforts, artificial intelligence applications including expert systems. verification and validation methods and other software applications on telecommunication systems. Operating systems. interfaces, data processing techniques, simulation models and algorithms and interactive programming are also considered.
A useful measure of reliability in a distributed processing system (DPS) is the terminal reliability between a pair of nodes, which is the probability that at least one communication path exists between these two node...
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ISBN:
(纸本)0818605669
A useful measure of reliability in a distributed processing system (DPS) is the terminal reliability between a pair of nodes, which is the probability that at least one communication path exists between these two nodes. An interesting optimization problem is that of maximizing the terminal reliability between a pair of nodes under a given budget for improving individual components' reliabilities. Three iterative algorithms for such maximization are presented. The first two algorithms require the computation of a terminal reliability expression and are therefore efficient for only small networks. The third algorithm, which is developed for larger DPSs, does not require the evaluation of the terminal reliability expression;this algorithm maximizes an approximate objective function and gives fairly accurate results. Several examples illustrate this approximate maximization algorithm, and the error involved is estimated.
An analytic model for estimating the task response in loosely coupled distributedsystems.is introduced. The model considers such factors as the precedence relationships among software modules, interprocessor communic...
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ISBN:
(纸本)0818605669
An analytic model for estimating the task response in loosely coupled distributedsystems.is introduced. The model considers such factors as the precedence relationships among software modules, interprocessor communication, interconnection network delay, module scheduling policy, and assignment of modules to computers. Simulation experiments are used to validate the assumptions of the analytic model. Applications of the model to the study of design issues for distributedsystems.such as module assignment, precedence relationships, module scheduling policies, and database management algorithms are discussed.
In this paper the authors briefly present the design of a distributed relational data base system. Then, they discuss experimental observations of the performance of that system executing both short and long commands....
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In this paper the authors briefly present the design of a distributed relational data base system. Then, they discuss experimental observations of the performance of that system executing both short and long commands. Conclusions are also drawn concerning metrics that distributed query processing heuristics should attempt to minimize. Lastly, they comment on architectures which appear viable for distributed data base applications.
A database management system was designed and implemented for the 5ESS switching system. The database is distributed and subject to stringent real time constraints and reliability requirements. A relational model is c...
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ISBN:
(纸本)0818605014
A database management system was designed and implemented for the 5ESS switching system. The database is distributed and subject to stringent real time constraints and reliability requirements. A relational model is chosen for this specialized database management system. This paper focuses on the reliability aspects of the design and how the balance between real-time constraints and reliability requirements is maintained. The concurrency control mechanism plays a significant role in achieving that balance by providing real-time access to call processing and also maintaining a consistent view of the data.
Two design rules which aid the construction of distributed computing systems.and the provision of fault tolerance are described, namely that: (i) a distributed computing system should be functionally equivalent to the...
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ISBN:
(纸本)0818605014
Two design rules which aid the construction of distributed computing systems.and the provision of fault tolerance are described, namely that: (i) a distributed computing system should be functionally equivalent to the individual computing systems.of which it is composed, and (ii) fault tolerant systems.should be constructed from generalized fault tolerant components. The reasoning behind these two 'recursive structuring principles', and the consequences of attempting to adhere to them, are discussed. Where appropriate this discussion is illustrated by reference to a distributed system based on UNIX that is now operational at Newcastle and several other locations. This system has been implemented by adding a software subsystem, known as the Newcastle Connection, to each of a set of UNIX systems. By this means the authors has constructed a distributed system which is functionally equivalent at both the user and the program level to a conventional uniprocessor UNIX system.
The use of logs to provide recovery from failures in transaction systems.is well known. Checkpointing is also a familiar technique for speeding restart from failures. However, most work on logs and checkpointing has c...
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ISBN:
(纸本)0818605014
The use of logs to provide recovery from failures in transaction systems.is well known. Checkpointing is also a familiar technique for speeding restart from failures. However, most work on logs and checkpointing has considered only centralized systems. In this paper a logging, checkpointing, and restart mechanism is described for distributedsystems. Moreover, nested transactions are used to enhance the performance and flexibility of the design. The result is that actions occurring at different sites can be significantly decoupled while avoiding any domino effect. Further, unreliability of one site has a limited impact on performance elsewhere.
In this paper the authors present fault-tolerant softwarereliability models based on component reliabilities. Two methods for estimating component reliabilities and the associated variances are given along with an ap...
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ISBN:
(纸本)0818605014
In this paper the authors present fault-tolerant softwarereliability models based on component reliabilities. Two methods for estimating component reliabilities and the associated variances are given along with an approach for calculating the system reliability estimate variance. The derived models are used as a basis for discussing trade-offs between the two dominate fault-tolerant software strategies, Recovery Blocks and N-Version Programming.
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