Several analytically solvable queueing models of multiprogramming with different jobs and various scheduling disciplines are investigated. It is shown that the analysis of these models supports the optimality of the a...
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Queueing network models of computer systems with multiprogramming constraints generally do not possess a product-form solution in the sense of Jackson. Therefore, one is usually led to consider approximation technique...
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ISBN:
(纸本)9780897910798
Queueing network models of computer systems with multiprogramming constraints generally do not possess a product-form solution in the sense of Jackson. Therefore, one is usually led to consider approximation techniques when dealing with such models. Equivalence and decomposition is one way of approaching their solution. With multiple job classes, the equivalent network may be viewed as a set of interdependent queues. In general, the state-dependence in this equivalent network precludes a product-form solution, and the size of its state space grows rapidly with the number of classes and of jobs per class. This paper presents two methods for approximate solution of the equivalent state-dependent queueing network. The first approach is a manifold application of equivalence and decomposition. The second approach, less accurate than the first one, is a fast-converging iteration whose computational complexity grows near-linearly with the number of job classes and jobs in a class. Numerical examples illustrate the accuracy of the two methods.
The design and implementation of a microcomputer network to support laboratory automation is described and discussed. It is a multi-level hierarchical star network connected to a multiprogrammed computer on which all ...
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The design and implementation of a microcomputer network to support laboratory automation is described and discussed. It is a multi-level hierarchical star network connected to a multiprogrammed computer on which all program development is done. The system is capable of supporting a large number of experimental setups. The microcomputers are either used as (1) local microcomputers for experiment control, (2) multiplexers for other microcomputers or (3) controllers for peripherals known in the multiprogrammed computer. The system combines the advantages of a large multiprogrammed computer with those of a small cheap dedicated computer close to the experiment. Character-oriented peripherals are connected to the multiprogrammed computer only. This reduces the amount of system software to be written for the network by an order of magnitude and eliminates the need for interfacing to existing small computer software. The system software consist of three small programs (monitors) providing a process concept and multibuffering of data in the involved computers. The monitor establishes a hierarchy of control and they eliminate the need for any local load device for the microcomputers as their monitors are in a read-only store. The system developed is designed for control of experiments in an environment where the experiments and the control strategies change with time and where the data refinement required is beyond what can be done on the present generation of microcomputers.
Analytic queueing models of programs with internal concurrency are considered. The program behavior model allows a process to spawn two or more concurrent tasks at some point during its execution. Except for queueing ...
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Analytic queueing models of programs with internal concurrency are considered. The program behavior model allows a process to spawn two or more concurrent tasks at some point during its execution. Except for queueing effects, the tasks execute independently of one another, and at the end of their execution, either wait for all of their siblings to finish execution or merge with the parent if all have finished execution. Two approximate solution methods for the performance prediction of such systems are developed, and results of the approximations are compared to those of simulations. The approximations are both computationally efficient and highly accurate. The gain in performance due to multitasking and multiprocessing is studied with a series of examples.
Although the effectiveness of the knee criterion as a virtual memory management strategy is widely accepted, it has been impossible to take advantage of it in a practical system, because little information is availabl...
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Although the effectiveness of the knee criterion as a virtual memory management strategy is widely accepted, it has been impossible to take advantage of it in a practical system, because little information is available about the program behavior of executing jobs. A new memory management technique to achieve the knee criterion in a multiprogrammed virtual memory system is developed. The technique, termed the optimum working-set estimator (OWE), abstracts the programs' behavior from their past histories by exponential smoothing, and modifies their working set window sizes in order to attain the knee criterion.
Probably the most basic reason behind the absence of a general treatment of resource allocation in modern computer systems is an adequate model for program behavior. In this paper a new model, the “working set model,...
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The paper deal s with the computation of performance measures when executing batch workloads on a multi programmed computer system. The computer system is modelled using a queueing network. model and the jobs are char...
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One of the common uses of bitmap terminals is storing multiple programming contexts in multiple, possibly overlapping, areas of the screen called windows. Windows traditionally store the visible state of a programming...
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The paper deals with the computation of performance measures when executing batch workloads on a multiprogrammed computer system. The computer system is modelled using a queueing network model and the jobs are charact...
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