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Showing papers in "Ibm Systems Journal in 1966"


Journal ArticleDOI
TL;DR: One of the basic limitations of a digital computer is the size of its available memory; an approach that permits the programmer to use a sufficiently large address range can accomplish this objective, assuming that means are provided for automatic execution of the memory-overlay functions.
Abstract: One of the basic limitations of a digital computer is the size of its available memory. 1 In most cases, it is neither feasible nor economical for a user to insist that every problem program fit into memory. The number of words of information in a program often exceeds the number of cells (i.e., word locations) in memory. The only way to solve this problem is to assign more than one program word to a cell. Since a cell can hold only one word at a time, extra words assigned to the cell must be held in external storage. Conventionally, overlay techniques are employed to exchange memory words and external-storage words whenever needed; this, of course, places an additional planning and coding burden on the programmer. For several reasons, it would be advantageous to rid the programmer of this function by providing him with a “virtual” memory larger than his program. An approach that permits him to use a sufficiently large address range can accomplish this objective, assuming that means are provided for automatic execution of the memory-overlay functions.

1,708 citations


Journal ArticleDOI
TL;DR: An iterative method for obtaining an approximation solution to an optimum network is presented and it is assumed that an acceptable line utilization factor is given.
Abstract: A teleprocessing system may include many low-speed terminals at great distances from the computing center. Specification of a communication network for connecting the remote terminals to the central computer constitutes an important design problem. An iterative method for obtaining an approximation solution to an optimum network is presented. The method assumes that an acceptable line utilization factor is given.

209 citations


Journal ArticleDOI
TL;DR: To provide estimates of device utilizations, queue lengths, and response times, a queuing model for a hypothetical auxiliary-storage system is formulated and analyzed.
Abstract: To provide estimates of device utilizations, queue lengths, and response times, a queuing model for a hypothetical auxiliary-storage system is formulated and analyzed. The limitations of the model are emphasized, as they are important in application of the model. On the other hand, useful ways of extending the utility of the model are also discussed.

67 citations


Journal ArticleDOI
TL;DR: Emphasis is placed on the functional scope of the system, on the motivating objctives and basic design concepts, and on the design approach to modularity.
Abstract: A brief outline of the structural elements of OS/360 is given in preparation for the subsequent sections on control-program functions. Emphasis is placed on the functional scope of the system, on the motivating objctives and basic design concepts, and on the design approach to modularity.

25 citations


Journal ArticleDOI
TL;DR: This paper discusses general considerations that arise in the statistical analysis of point stochastic processes and a computer program designed to implement such an analysis, called SASE, which is written as a sequence of independent subroutines.
Abstract: This paper discusses general considerations that arise in the statistical analysis of point stochastic processes (series of events) and a computer program called SASE designed to implement such an analysis. The program is written as a sequence of independent subroutines. The computations performed in each subroutine are described and an example of an analysis of a series of events is presented and discussed.

25 citations


Journal ArticleDOI
TL;DR: Concepts underlying the data-management capabilities of OS/360 are introduced; distinctive features of the access methods, catalog, and relevant system macroinstructions are discussed.
Abstract: Concepts underlying the data-management capabilities of OS/360 are introduced; distinctive features of the access methods, catalog, and relevant system macroinstructions are discussed. To illustrate the way in which the control program adapts to actual input/output requirements, a read operation is examined in considerable detail.

23 citations


Journal ArticleDOI
TL;DR: This part of the paper discusses the control-program functions most closely related to job and task management, as well as those that support multitask operation.
Abstract: This part of the paper discusses the control-program functions most closely related to job and task management. Emphasized are design features that facilitate diversity in application environments as well as those that support multitask operation.

14 citations


Journal ArticleDOI
TL;DR: A queuing model for a non-priority time-sharing environment in which all active tasks fit in a homogeneous main storage is discussed, providing a basic frame of reference for the development of more complicated models.
Abstract: This paper discusses a queuing model for a non-priority time-sharing environment in which all active tasks fit in a homogeneous main storage. Design parameters such as queue length and response time, as well as their distributions, can be estimated with the aid of the model. The model provides a basic frame of reference for the development of more complicated models.

12 citations


Journal ArticleDOI
TL;DR: The main considerations involved in choosing between general-purpose and special-purpose simulators are commented on.
Abstract: As a tool for quantitative investigation, digital simulation is especially suited to the study of stochastic processes having many interdependent variables. Not only can a simulation model be modijied to reflect structural changes in a process, but it can be used to gain insights during the design of the process. These properties recommend the use of digital simulators in the design of complex teleprocessing systems. This paper comments on the main considerations involved in choosing between general-purpose and special-purpose simulators.

6 citations


Journal ArticleDOI
J. P. Bricault1, I. Delgalvis
TL;DR: A queuing model that approximates the most typical mode of operation is formulated and solutions for the number of buffers required by the pool are obtained.
Abstract: The problem of allocating main storage for a message-segment buffer pool is considered. A queuing model that approximates the most typical mode of operation is formulated. Solutions for the number of buffers required by the pool are obtained. Although the solutions require iterative computational methods, they are not difficult to program. Inasmuch as the model and solution methods both involve approximations, the validity of the approach was checked by simulating a typical set of operating conditions. Although the computational results were found to be conservatively biased, the method is clearly adequate for most design purposes.

6 citations


Journal ArticleDOI
TL;DR: The macro language design discussed in this paper provides a systematic means by which the SYSTEM/360 assembler-language programmer can develop macroinstructions, thereby expanding the set of machine-oriented instructions that serve as the basis of the assembler language.
Abstract: The macro language design discussed in this paper provides a systematic means by which the SYSTEM/360 assembler-language programmer can develop macroinstructions, thereby expanding the set of machine-oriented instructions that serve as the basis of the assembler language. Also treated is the format of macro definitions, the design of a macro generator, and the principal considerations that governed the design of the system as a whole.

Journal ArticleDOI
TL;DR: Matrices are introduced to represent the set or sets of difference equations associated with a merge-sort and various properties of the Class Ia merge-sorts are shown to be obtainable by matrix multiplication.
Abstract: Previous work, which analyzed certain merge-sorting methods with the aid of difference equations, is extended to include a wider range of methods. Matrices are introduced to represent the set or sets of difference equations associated with a merge-sort. Two or more matrices are required to define a Class II method, whereas a Class I method can be defined with one matrix. The merge-sorts of most interest fall into a special subclass called Class Ia. It is shown that an asymptotic solution to the set of diflerence equations for a Class Ia merge-sort is readily obtainable. Carter's analysis of cascade and polyphase merge-sorts is generalized and extended to include, among other things, the compromise merges. Various properties of the Class Ia merge-sorts, including relative performance measures and explicit merge patterns, are shown to be obtainable by matrix multiplication. Although the analysis emphasizes Class Ia merges, suggestions are given for applying the matrix technique to other merge-sorts of Classes I and II.

Journal ArticleDOI
TL;DR: A functional classification of teleprocessing applications is given, a schematic of a basic teleprocessing system is introduced, and the relative merits of mathematical analysis and digital simulation are discussed.
Abstract: For analytical purposes, a teleprocessing system can be characterized as a digital computer with unscheduled inputs from a number of remote points. In the design of such a system, various queuing problems arise as a consequence of the unscheduled inputs, and the necessity of linking remote points to the central computer leads to a problem in combinatorial mathematics. To show the origin of these problems, a functional classification of teleprocessing applications is given, a schematic of a basic teleprocessing system is introduced, and the relative merits of mathematical analysis and digital simulation are discussed.

Journal ArticleDOI
TL;DR: The extrapolated Liebmann method for solving partial differential equations is selected for study, and Kernel programs are included, and timing formulas needed in making comparisons of various configurations of two computers are developed.
Abstract: The extrapolated Liebmann method for solving partial differential equations is selected for study. With typical computer characteristics in mind, several schemes for organizing the requisite data flow are discussed. To show the potentialities of timing formulas, as well as their limitations and the problems encountered in their construction, one of the data-flow schemes is treated at length. Kernel programs are included, and timing formulas needed in making comparisons of various configurations of two computers are developed.

Journal ArticleDOI
TL;DR: A procedure is given for computaion of ex using tables of coefficient of the economized approximating polynomical over a range of positive and negative x to test effectiveness of table lookup methods in the computation of elementary functions.
Abstract: A procedure is given for computaion of ex using tables of coefficient of the economized approximating polynomical over a range of positive and negative x. A related procedure that uses continued fractions is also discussed. The exponential functions was selected to test effectiveness of table lookup methods in the computation of elementary functions. The number of multiplications or divisions required of standard methods is compared with the number required when table lookup is employed.