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IBM Systems Journal

Issue 2 • Date 1971

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Displaying Results 1 - 6 of 6
  • The formal description of programming languages

    Page(s): 86 - 112
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2149 KB)  

    The formal description methods introduced in this paper were related to our simple language SPL for explanation purposes. Actually, the methods (i.e., abstract trees, predicates, state components, control trees, etc.) apply to all programming languages. However, some programming languages contain facilities that cannot be expressed using the methods described in this paper alone. For example, additional definitions are required to represent the multitasking facilities of PL/1. To solve this particular problem, an extension to the execution control of the abstract interpreter was used in the formal description of PL/1. View full abstract»

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  • Simulation of a model of paging system performance

    Page(s): 113 - 128
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1732 KB)  

    This paper compares three simulation methods with straightforward sampling to study the efficiency of these methods in estimating the performance of a demand-paging system model. Measures of system overhead, queuing delays, and transient response of the modeled system are related to parameters describing the processing demands of the programs load. Our results for this specific system model suggest that variance reduction from straightforward sampling techniques is obtainable by the method of antithetic variables. However, one should not necessarily expect a similar gain for all response variables in a model. With regard to variance reduction, additional gains may be obtainable by a combination of stratification and antithetics. View full abstract»

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  • An analysis of the machine interference model

    Page(s): 129 - 142
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1369 KB)  

    The asymptotic properties of the machine interference model were described in this paper. When the properties of the system were appropriately normalized and represented in terms of the variable w (=nu/v), the size dependencies of these properties were of order 1/n in regions of the most interest, that is, w < 1. Furthermore, the model displayed a functionally different behavior in the region w ≥ 1. The region around w = 1 was described as an unstable region in which an equivalent simulation model could be expected to stabilize slowly and probably give results different from the mathematical model. The asymptotic formulas are simple in form and quite accurate, and they allow the performance of queuing analysis with very little effort. In the last section of the paper, the solution and the properties of the generalized machine interference model were given. View full abstract»

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  • A computer graphics system for block diagram problems

    Page(s): 143 - 161
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1722 KB)  

    This paper has described the design of an experimental system intended for solving complex problems. Facilities are provided for stating a problem as a labeled block diagram of arbitrary complexity. A block diagram can be drawn on a representative sheet that is many times larger than the screen of the cathode-ray tube. The block diagram may be structured into a hierarchy of sheets allowing blocks to be designed and specified by the user. The modeling subsystem provides a number of viewports so that more than one sheet can be displayed. To make entering of block diagrams easier, a drawing package that does not require commands for creating the diagram but uses only the operands to determine the command is a part of the system. Finally, a data structure in the host computer is provided to allow for easy access to data by any application program. View full abstract»

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  • Authors

    Page(s): 162 - 163
    Save to Project icon | PDF file iconPDF (1061 KB)  
    Freely Available from IEEE
  • Abstract

    Page(s): 164 - 165
    Save to Project icon | PDF file iconPDF (876 KB)  
    Freely Available from IEEE

Aims & Scope

Throughout its history, the IBM Systems Journal has been devoted to software, software systems, and services, focusing on concepts, architectures, and the uses of software.

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Editor-in-Chief
John J. Ritsko
IBM T. J. Watson Research Center5