ER nets are an extension of Petri nets and suitable for finding solutions to a wide spectrum of problems. The author's idea is to use ER nets not only in the early stages of software development (e.g. specificatio...
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ER nets are an extension of Petri nets and suitable for finding solutions to a wide spectrum of problems. The author's idea is to use ER nets not only in the early stages of software development (e.g. specification and simulation), but also for real application-execution. The author suggests the use of a virtual computer, based upon ER formalism, ensuring an adequate environment for the entire application life cycle. The reason for such a decision was the good results obtained in Tools Manager development (J. Strucl, 1990), within the framework of the NETwork project (M. Braga et al., 1990). The high-level Petri nets represent parallel tasks in a very intuitive way and thus are regarded as natural tools for solving a wide range of problems. The vision is an environment for the work with ER nets where these are used for problem specification, simulation, prototype building, for final program, support tools, the environment in which the individual stages are not separated, but they are intermingled and represent an entity. The prototype may thus at the same time be the final program, and specification also the documentation.< >
NASA Technical Reports Server (Ntrs) 19900017242: Single-Pass Memory System Evaluation for multiprogramming Workloads by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 19900017242: Single-Pass Memory System Evaluation for multiprogramming Workloads by NASA Technical Reports Server (Ntrs); published by
The generating function approach for analysing queueing systems has a long-standing tradition. One of the highlights is the seminal paper by Kingman [Ann. Math. Statist., 32(1961), pp. 1314–1323] on the shortest-queu...
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The generating function approach for analysing queueing systems has a long-standing tradition. One of the highlights is the seminal paper by Kingman [Ann. Math. Statist., 32(1961), pp. 1314–1323] on the shortest-queue problem, where the author shows that the equilibrium probabilities pm,n
Although sometimes thought of as only a component of time-sharing operation, multiprogramming can involve broader questions of resource allocation, since fairness is not required to meet a response criterion. In a mul...
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Although sometimes thought of as only a component of time-sharing operation, multiprogramming can involve broader questions of resource allocation, since fairness is not required to meet a response criterion. In a multi-programmed system. it may serve maximal resource use to be unfair, for example by holding an input.: output channel idle for a program while it completes a small amount of processor usage, enabling further use of the channel. Several applications of this principle are given, and it is suggested that a multiprogramming executive might dynamically adjust its allocation algorithms to gain efficiency. Allocation of resources is closely connected to accounting for those resources, raising the problems of repeatability, minimal uncharged overhead, and relative weighting of charges for dependent resources. Since weightings may depend on allocation algorithms, these are not arbitrary accounting parameters. Often the only repeatable accounting is one which omits an extensive overhead; this overhead can be multiple-charged to all programs which benefit from it, so that in the worst case the overhead will be paid, and should multiprogramming prove efficient, overcharges will result. multiprogramming turns on allocation of the memory resource essential to control of other resources. The general suggestions for allocation and accounting are applied to this question, and some details provided for the case of a monitor which controls a virtual-memory machine. [ABSTRACT FROM AUTHOR]
This paper investigates the problem of scheduling a processor to optimize throughput in a multiprogramming environment. A deterministic model is used to study the scheduling of a batch of k programs residing in main m...
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This paper investigates the problem of scheduling a processor to optimize throughput in a multiprogramming environment. A deterministic model is used to study the scheduling of a batch of k programs residing in main memory of a system consisting of a single processor and k input–output devices in such a way as to minimize the time to complete all k jobs.
A simple cyclic-queue model of a multiprogramming system with a fixed number of tasks is analyzed in its steady state. Expressions for queue-size distribution, average rate of job completions, and average stay-in-the-...
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Microscopic level Job stream data obtained in a production environment by an event-driven software probe is used to drive a model of a multiprogramming computer system. The CPU scheduling algorithm of the model is sys...
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Microscopic level Job stream data obtained in a production environment by an event-driven software probe is used to drive a model of a multiprogramming computer system. The CPU scheduling algorithm of the model is systematically varied. This technique, called trace-driven modeling, provides an accurate replica of a production environment for the testing of variations in the system. At the same time alterations in scheduling methods can be easily carried out in a controlled way with cause and effects relationships being isolated. The scheduling methods tested included the best possible and worst possible methods, the traditional methods of multiprogramming theory, round-robin, first-come- first-served, etc., and dynamic predictors. The relative and absolute performances of these scheduling methods are given. It is concluded that a successful CPU scheduling method must be preemptive and must prevent a given job from holding the CPU for too long a period. [ABSTRACT FROM AUTHOR]
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