Showing papers on "Scheduling (computing) published in 1969"

Multiproject Scheduling with Limited Resources: A Zero-One Programming Approach

Abstract: A zero-one 0-1 linear programming formulation of multiproject and job-shop scheduling problems is presented that is more general and computationally tractable than other known formulations. It can accommodate a wide range of real-world situations including multiple resource constraints, due dates, job splitting, resource, substitutability, and concurrency and nonconcurrency of job performance requirements. Three possible objective functions are discussed; minimizing total throughput time for all projects: minimizing the time by which all projects are completed i.e., minimizing makespan; and minimizing total lateness or lateness penalty for all projects.

Prevention of system deadlocks

Abstract: A well-known problem in the design of operating systems is the selection of a resource allocation policy that will prevent deadlock. Deadlock is the situation in which resources have been allocated to various tasks in such a way that none of the tasks can continue. The various published solutions have been somewhat restrictive: either they do not handle the problem in sufficient generality or they suggest policies which will on occasion refuse a request which could have been safely granted. Algorithms are presented which examine a request in the light of the current allocation of resources and determi.~e whether or not the granting of the request will introduce the possibility of a deadlock. Proofs given in the appendixes show that the conditions imposed by the algorithms are both necessary and sufficient to prevent deadlock. The algorithms have been successfully used in the THE system.

Optimal Preemptive Scheduling on Two-Processor Systems

Abstract: One of the important potentials of multiprocessor systems is the ability to speed the completion of a computation by concurrently processing independent portions of the job. In this paper we consider the static scheduling of computations for a system containing two indentical processors. The object is to complete the computation in the minimum amount of time. A computation is assumed to be specified as a partially ordered set of tasks and the execution time for each task. A solution for the two-machine case with preemptive scheduling is presented.

Error detection and correction system with statistically optimized data recovery

Abstract: A statistically optimized data recovery apparatus in a system having data storage and retrieval means, said apparatus including error detection means, a plurality of error correction means, first schedulers for scheduling a plurality of error correction attempts, and a second scheduler and a parameter variation means, said second scheduler providing for ordered selection of the first scheduler, and said parameter variation means providing for variation of parameters of said retrieval means, in an attempt to recover data in error.

Erratum: `` Analysis of a Drum Input/Output Queue Under Scheduled Operation in a Paged Computer System''

Abstract: Properly scheduling the usage of input output devices is an important aspect of the design of modern multiprogramming systems featuring a paged environment. In this paper magnetic drums in the role of auxiliary memories are studied in the context of these systems. It is the nature of the drum, its usage by the system, and the organization of information on the drum are discussed in the light of current system designs. Mathematical models are then defined such that two extremes in scheduling disciplines are represented in a system in which page requests are assumed to arrive singly and at random. The analysis leads to results for a measure of drum utilization, a generating function for the queue length probabilities in equilibrium, the mean queue length, and the mean waiting time. Finally, the significance of the results is discussed along with some examples.

The Sequencing Problem

Abstract: This paper surveys methods proposed in the literature for determining the optimal solution to “N Job, M Machines” scheduling problems when there are no due dates or priorities and the sole objective is to complete all operations in least time.

Scheduling Local and Express Service

Abstract: A common carrier transportation service, say a train, operates between points A and B. There are two classes of service—an express that goes directly from A to B and a local that makes one or more intermediate stops. The local, quite naturally, takes longer than the express. A model is developed for finding a jointly optimal schedule of local and express service. The model is solved by dynamic programming.

Some principles of time-sharing scheduler strategies

Abstract: Fundamental considerations in time and space scheduling for time-sharing systems are reviewed. Workload components are classified as trivial and nontrivial foreground, and background. Each has certain resource-use and required response properties. A central issue in scheduling is the degree of advance knowledge available to the scheduler about calls on system resources. This provides a theme for classifying several algorithms. A response figure of merit believed to be helpful in understanding time-sharing schedulers is defined. Simulation results using a very simple workload and system model are included in the discussion. A summary is given of some major issues in scheduling for time-sharing and virtual systems.

Process management and resource sharing in the multiaccess system "ESOPE"

Abstract: This paper describes the main design principles of the multiaccess system ESOPE. Emphasis is placed on basic ideas underlying the design rather than on implementation details. The main features of the system include the ability given to any user to schedule his own parallel processes, using system primitive operations, and the allocation/scheduling policy, which dynamically takes into account recent information about user behaviour.

Job shop scheduling by means of simulation and an optimum-seeking search

Abstract: The paper discusses a job shop simulator designed for use in the scheduling of a set of jobs. The simulator has been implemented in the form of a Fortran program. The simulator can be used in conjunction with a search program that adjusts priority rule parameters in seeking an improved schedule.

Priority Assignment in a Network of Computers

Abstract: This research is aimed at developing analytical tools for system modeling and analysis of real-time computer networks. We formulate an idealized mathematical model for a multiserver system with a finite length nonpreemptive priority queue.

Equipment Configuration in Balanced Computer Systems

Abstract: A computer system is said to be balanced whenever the set of running programs presents a total demand, for both processors and memory, that matches the available equipment. The equipment configuration, here defined as the proper relative capacities of processor and memory resources in a balanced computer system, may be determined analytically.

An Interrupt Based Organization for Management Information Systems

Abstract: A programming structure, language constructs, and supervisorry system organization are proposed for the design and coding of large shared data base systems. The bases for this organization are a generalized interrupt structure and the newly introduced concept of ``file tagging'''', which is the process of associating program structures and interrupt generating conditions with items in the data base. An algorithm for resolving conflicts which arise in scheduling the interrupt processing routines is presented. DPL, a programming language and supervisory system in which these concepts are implemented, is used to illustrate the new organization which is proposed for management information systems. Keywords and phrases: management information systems, integrated data processing, supervisors, interrupts, monitoring systems, supervisory systems, interrupt scheduling, parallel processing.

The effects of sleep loss and demanding work/rest cycles: an analysis of the traditional navy watch system and a proposed alternative

Abstract: : An analysis of the traditional Navy watch system and a proposed alternative is presented. Current research on sleep deprivation and the effects of demanding work/rest schedules is documented and discussed as a basis for key assumptions in the analysis. Methodology is also presented for determining the relative ability of the two schedules to meet the assumed minimum sleep requirements. The results favor the alternate schedule as efficient for allocating available time resources to meet established sleep requirements.

Models of Pure time-sharing disciplines for resource allocation

Abstract: Pure time sharing (PTS) disciplines are those which involve in some way the simultaneous sharing of a processor or other service facility by more than one job at a time. Implicit is the requirement that the total processor capacity is fixed so that individual job processing rates are reduced according as the number of jobs sharing the processor increases. In this paper the general class of such disciplines is surveyed and studied by the investigation of the behavior of mathematical models.By the introduction of appropriate algorithms it is shown how these disciplines can be applied to static processor scheduling problems in which total schedule time is to be minimized. Application of these disciplines to queueing systems is also examined, yielding characterizations which classify the performance measures optimized. The PTS disciplines discussed include one which bases scheduling decisions on the elapsed times of jobs and one which bases decisions on the expected remaining processing times of jobs. The simplest PTS discipline studied is one which makes no explicit use of any processing time information.

Complementary replacement: a meta scheduling principle

Abstract: A principle of scheduling is presented that includes a wide class of time and space allocation problems met in time sharing and virtual systems. Its essence is a method, based on symmetry, to use any of several rules for admission-to-service in a single server system to derive a space-replacement rule. This method, called complementary replacement includes several known job dispatching rules as well as some page-replacement algorithms such as the MIN and LRU (last-recently-used). A fundamental but unsolved problem with the principle is its range of applicability and the conditions under which it guarantees an optimum.

Championship Techniques in Track and Field

Abstract: WEB SITE FOR OPERATING SYSTEMS, INTERNALS AND DESIGN PRINCIPLES PREFACE PART ONE: BACKGROUND 1. Computer System Overview 2. Operating System Overview PART TWO: PROCESSES 3. Process Description and Control 4. Threads, SMP, and Microkernels 5. Concurrency: Mutual Exclusion and Synchronization 6. Concurrency: Deadlock and Starvation PART THREE: MEMORY 7. Memory Management 8. Virtual Memory PART FOUR: SCHEDULING 9. Uniprocessor Scheduling 10. Multiprocessor and Real-Time Scheduling PART FIVE: INPUT/OUTPUT AND FILES 11. I/O Management and Disk Scheduling 12. File Management PART SIX: DISTRIBUTED SYSTEMS 13. Distributed Processing, Client/Server, and Clusters 14. Distributed Process Management PART SEVEN: SECURITY 15. Computer Security Appendix 15A Encryption

The Optimization of Paper Machine Scheduling

Abstract: A method for determining schedules in a paper mill is described and applied to real production data. The problem is to allocate products to machines and determine their sequence so as to minimize total costs. The costs include production losses through set-ups, stock holding and penalties for delayed delivery. The method is based on a permutation representation of the production schedule and the determination of a locally optimal solution. A permutation is locally optimal if it cannot be improved by transferring groups of products to a different place in the schedule. The method has been programmed and the results show a considerable improvement over alternative manual procedures. The paper has been written in two parts, the first dealing with the development of the method and the second discussing its application to a specific problem.

Optimal Scheduling for Cyclic Steam Injection Projects

Abstract: A well steam-injection scheduling model which maximizes the profit per day for oil production leases is discussed. The model can be used to produce operating resteaming schedules and to evaluate the profitability for any number of steam generators. There are no limitations on the size of the problem which can be handled by this approach exclusive of computer storage capability and run time. The model consists of nonlinear regression, nonlinear optimization, and a scheduling algorithm. Weekly well-production data from a production-reporting system are utilized to extend the system to a reporting, operating control, and plannning system that not only provides management with production history, but analysis tools for better decisions as well.

An algorithm for aircraft scheduling in a radial network

Abstract: This paper deals with the aircraft scheduling problems of an airline with a radial network. Within such a network it is relatively easy to determine whether or not a newly suggested time table for a given tupe of aircraft can be implemented with the available fleet, but it is not so easy to see the possibilities for maintenance, instruction flights etc., which the time table offers. Moreover, one has to cope with the constraint, that specific flights are committed to only one of the subtypes of a given aircraft type. This means that the flights have to be grouped and that each group of flights must be assigned to the fleet of one of the subtypes. In practice, there are many feasible solutions and this report suggests a method to generate those solutions, starting from the draft time table. This method, based on a branch and bound algorithm is also applicable to the solution of other problems. As an illustration the daily pairing phase of the European crew scheduling problem is discussed in the last chapter.

Service Hours in Selected Academic Libraries

Abstract: MANY COLLEGE and university libraries are being pressed to remain open into the early morning hours and in some cases to remain open twenty-four hours a day. In order to determine how many hours weekly their libraries were open, a questionnaire was sent recently to forty-three selected state and private universities. Thirty-six questionnaires were returned. The average library in this group stayed open 94.3 hours a week. One stayed open 110 hours a week, while another stayed open only 81 hours a week. The closing time of the libraries is as follows:

Planning and scheduling jobs on a computer using cpm

Abstract: : The report presents by example the application of the critical path method (CPM) for the planning and scheduling of jobs on a computer It provides a step-by-step preparation and analysis of a network representation of a computer system application Also included is a glossary of relevant terms and a fairly comprehensive bibliography on the subject of CPM/PERT, scheduling and sequencing