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IBM Journal of Research and Development

Issue 2 • Date April 1957

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Displaying Results 1 - 15 of 15
  • Table of Contents

    Publication Year: 1957, Page(s): 101
    IEEE is not the copyright holder of this material | PDF file iconPDF (161 KB)
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  • A 32,000-Word Magnetic-Core Memory

    Publication Year: 1957, Page(s):102 - 109
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (546 KB)

    The development of the IBM 738 magnetic core storage unit is described and associated engineering problems are discussed, including the electrical and mechanical arrangements for packaging more than one million magnetic cores and their circuits. This paper describes the driver circuits and the sense amplifier used for this system. View full abstract»

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  • Computation of eN for −∞<N<+∞

    Publication Year: 1957, Page(s):110 - 115
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (482 KB)

    Rational R and polynomial P approximations to the exponential function eN are studied. They allow eN to be computed for any value of the exponent N in the infinite range from minus infinity to plus infinity a minimum number M of multiplications (and divisions, for the rational approximations). This minimum is attained without unduly increasing the number PC of precomputed and... View full abstract»

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  • The Multipurpose Bias Device—Part I: The Commutator Transistor

    Publication Year: 1957, Page(s):116 - 129
    Cited by:  Papers (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (689 KB)

    It is suggested that multipurpose devices will provide economy in both number and assortment of basic computer building blocks. A study is made of the Rutz commutator transistor largely in application to three-input, one-output logical situations. A basis is thereby provided for a more general analysis to be published at a later date. View full abstract»

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  • Addressing for Random-Access Storage

    Publication Year: 1957, Page(s):130 - 146
    Cited by:  Papers (15)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (669 KB)

    Estimates are made of the amount of searching required for the exact location of a record in several types of storage systems, including the index-table method of addressing and the sorted-file method. Detailed data and formulas for access time are given for an “open” system which offers high flexibility and speed of access. Experimental results are given for actual record files. View full abstract»

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  • The Lorenz Number

    Publication Year: 1957, Page(s):147 - 157
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (559 KB)

    The theory of the Lorenz number of a conducting crystal is developed for the common models of the electron assembly. For the one-electron model it is shown that, provided scattering is elastic to an approximation which is examined, the Lorenz number is equal to the square fluctuation of the thermoelectric power. For the phenomenological band model an equivalent result is obtained. It is hypothesiz... View full abstract»

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  • A Positive-Integer Arithmetic for Data Processing

    Publication Year: 1957, Page(s):158 - 170
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (568 KB)

    It is hypothesized that positive numbers suffice for the expression of quantities in accounting. New arithmetic operations are devised that yield non-negative results in computation, and the applicability of these operations to data processing is studied. These operations permit a wide variety of functions to be computed with fewer and less complex steps and imply the feasibility of constructing l... View full abstract»

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  • Irredundant Disjunctive and Conjunctive Forms of a Boolean Function

    Publication Year: 1957, Page(s):171 - 176
    Cited by:  Papers (27)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (339 KB)

    A thorough algebraic method is described for the determination of the complete set of irredundant normal and conjunctive forms of a Boolean function. The method is mechanical and therefore highly programmable on a computer. View full abstract»

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  • A Mathematical Model for Determining the Probabilities of Undetected Errors in Magnetic Tape Systems

    Publication Year: 1957, Page(s):177 - 180
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (293 KB)

    Mathematical models for evaluating the relative efficiencies of vertical and longitudinal redundancy-bit checking in magnetic tape systems are derived. Although these types of validity checking have been in use for some time, this is, to the authors' knowledge, the first quantitative statement of the probabilities associated with them. View full abstract»

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  • A Self-Clocking System for Information Transfer

    Publication Year: 1957, Page(s):181 - 184
    Cited by:  Papers (3)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (295 KB)

    This paper describes a circuit which generates a continuous train of clock pulses bearing a fixed phase relationship to information pulses. By switching two gated oscillators, the information pulses continuously correct the phase of the clock pulses. View full abstract»

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  • A Symmetrical-Transistor Steering Circuit

    Publication Year: 1957, Page(s):185 - 188
    Cited by:  Patents (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (366 KB)

    1. The greatest advantage of the circuit as fas as binary triggering is concerned seems to be that simultaneous triggering at both bases can be used. This reduces the regeneration time in the flip-flop. 2. The circuit is quite sensitive to changes in input level. This can be overcome by application of a bias at the input which is greater that the anticipated noise level. 3. The symmetrical circuit... View full abstract»

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  • Determination of Transient Response of a Drift Transistor Using the Diffusion Equation

    Publication Year: 1957, Page(s):189 - 191
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (332 KB)

    A mathematical model of a drift transistor has been constructed which enables us to study the time required for collector current to reach a steady value in response to a step function of current introduced at the emitter. IBM germanium drift transistors of the PNP type are being investigated. Various base widths and resistivities are being considered. The models devised are suitable for computati... View full abstract»

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  • IBM Technical Papers Published in Other Journals

    Publication Year: 1957, Page(s):192 - 193
    IEEE is not the copyright holder of this material | PDF file iconPDF (255 KB)
    Freely Available from IEEE
  • Recent IBM Patents

    Publication Year: 1957, Page(s): 194
    IEEE is not the copyright holder of this material | PDF file iconPDF (182 KB)
    Freely Available from IEEE
  • Authors

    Publication Year: 1957, Page(s):195 - 196
    IEEE is not the copyright holder of this material | PDF file iconPDF (210 KB)
    Freely Available from IEEE

Aims & Scope

The IBM Journal of Research and Development is a peer-reviewed technical journal, published bimonthly, which features the work of authors in the science, technology and engineering of information systems.

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Meet Our Editors

Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center