A multiprogramming system is described in which all activities are divided over a number of sequential processes. These sequential processes are placed at various hierarchical levels, in each of which one or more inde...
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The lack of overlap in CPU aml I/O processing in multiprogramming leads to an increase in run time for the tasks processed. Two techniques for improving the overlap, time Slicing and priority scheduling, are investiga...
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A multiprogramming operating system for the TI980A permits replacement of system primitives by a programmer familiar with the system's design and data structures. This paper describes the hardware features availab...
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ISBN:
(纸本)9781450374453
A multiprogramming operating system for the TI980A permits replacement of system primitives by a programmer familiar with the system's design and data structures. This paper describes the hardware features available;the method of use of the replaceable parts facility;typical student assignments for an operating systems course (e.g. ACM Curriculum'68 I4);and student reaction to the projects.
This paper defines a set of scheduling primitives which have evolved from multiprogramming systems described by Dijkstra, Lampson, Saltzer, and the present author. Compared to earlier papers on the same subject, the p...
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In recent papers [I,2] we have presented an analytical model of virtual memory system performance which was used to provide a characterization of thrashing and some insight into the behaviour of virtual memory compute...
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In recent papers [I,2] we have presented an analytical model of virtual memory system performance which was used to provide a characterization of thrashing and some insight into the behaviour of virtual memory computer systems. We pointed out the existence of an optimal degree of multiprogramming with respect to the central processing unit (CPU) utilization and it was shown that the value of the optimal degree of multiprogramming was closely related to such program behaviour parameters as locality and I/0 rate. These observations were used to support a method to control the degree of multiprogramming in a virtual memory computer system by estimating dynamically the activity of the resources of the system [2]. In this paper, we shall use the same analytical model to investigate the behaviour of the paging drum when the degree of multiprogramming is set to its optimal value. The main conclusion, which corroborates the general feeling on performance of virtual memory systems [3,-4, 5], is that drum utilization remains in the 50 % range whenever CPU utilization is maximized, if no resource is saturated. The results are validated through simulation experiments in order to relax some theoretical assumptions used in the analytical model and to take into account some detailed mechanisms such as CPU overheads. As an application, an adaptive control algorithm based on the activity of the paging device is proposed. The algorithm has been simulated and comparisons with results reported in [2] are presented. Moreover, after inveetigatiQns we show also that optimal performance can only be achieved through a balanced use of the different resources of the system. This conclusion cross-checks and extends Buzen's theoretical results [6] and Wulf's practical ones [73.
One of the most common ways to share a multiprocessor among several applications is to give each application a set of dedicated processors. To ensure fairness, an application may receive fewer processors than it has p...
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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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We model the limited buffer queueing process that occurs within the UNIX operating system's protocol processing layers. Our model accounts for the effects of user process multiprogramming and preemptive, priority ...
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CPU scheduling or dispatching in computer systems is surveyed. In order to study and evaluate a dispatching algorithm, a simulation model of a dispatching algorithm for multiprogramming operating system has been devis...
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In this paper, the following definitions have been followed: 1. multiprogramming - the time-sharing of a processor by many programs operating sequentially. Many programs are available and in memory but only one progra...
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