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IBM Journal of Research and Development

Issue 3 • May 1986

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Displaying Results 1 - 11 of 11
  • Key-sequence data sets on indelible storage

    Publication Year: 1986, Page(s):230 - 241
    Cited by:  Papers (12)  |  Patents (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1004 KB)

    Methods for creating and maintaining key-sequence data sets without overwriting the storage medium are described. These methods may be applied to erasable or to write-once storage devices, and they are compatible with conventional device error-management techniques. All past values of data records are preserved in a data structure called a Write-Once B-Tree. Rapid random access is available to rec... View full abstract»

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  • The average complexity of depth-first search with backtracking and cutoff

    Publication Year: 1986, Page(s):242 - 258
    Cited by:  Papers (6)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1220 KB)

    This paper analyzes two algorithms for depth-first search of binary trees. The first algorithm uses a search strategy that terminates the search when a successful leaf is reached. The algorithm does not use internal cutoff to restrict the search space. If N is the depth of the tree, then the average number of nodes visited by the algorithm is as low as O(N) and as high as O(2N) dependin... View full abstract»

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  • On-the-fly decoder for multiple byte errors

    Publication Year: 1986, Page(s):259 - 269
    Cited by:  Papers (5)  |  Patents (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (893 KB)

    Multiple-error-correcting Reed-Solomon or BCH codes in GF(2b) can be used for correction of multiple burst errors in binary data. However, the relatively long time required for decoding multiple errors has been among the main objections to applying these schemes to high-performance computer products. In this paper, a decoding procedure is developed for on-the-fly correction of multiple ... View full abstract»

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  • Design and performance of a magnetic head for a high-density tape drive

    Publication Year: 1986, Page(s):270 - 277
    Cited by:  Papers (10)  |  Patents (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (665 KB)

    The design of a magnetic head for use in the tape drive portion of the IBM 3480 Magnetic Tape Subsystem required that advances be made in track density and linear recording density while meeting requirements for signal quality, manufacturability, and reliability. The design that was developed to fulfill these needs combines ferrite pole-pieces, magnetoresistive read elements, and planar-deposited ... View full abstract»

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  • Symmetric stochastic Petri nets

    Publication Year: 1986, Page(s):278 - 293
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1055 KB)

    The stochastic Petri net (SPN) model is well suited to formal representation of concurrency, synchronization, and communication. In this paper we focus on discrete event simulation methods for SPN models with special structure and define a symmetric SPN. Exploiting properties of a symmetric SPN and underlying regenerative process structure, we establish steady state estimation procedures based on ... View full abstract»

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  • Compiling circular attribute grammars into Prolog

    Publication Year: 1986, Page(s):294 - 309
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (901 KB)

    This paper describes an algorithm for compiling attribute grammars into Prolog. The attribute grammars may include inherited and synthesized attributes and contain recursive (circular) definitions. The semantics of the recursive definitions is defined in terms of a fixed-point finding function. The generated Prolog code stands in direct relation to its attribute grammar, where logical variables pl... View full abstract»

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  • Least-squares storage-channel identification

    Publication Year: 1986, Page(s):310 - 320
    Cited by:  Papers (29)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (813 KB)

    Pulse (dibit) and step (transition) responses for magnetic-storage channels are important for detection-circuitry design and for comparison of various media, heads, and other channel components. This paper presents a least-squares procedure that can be used to identify the dibit and transition responses from measurements of the read-head response to any known data sequence written on the medium. T... View full abstract»

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  • A maximum-energy-concentration spectral window

    Publication Year: 1986, Page(s):321 - 325
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (422 KB)

    A time-discrete solution method is proposed for realization of a spectral window which is ideal from an energy concentration viewpoint. This window is one that concentrates the maximum amount of energy in a specified bandwidth and hence provides optimal spectral resolution. View full abstract»

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  • On yield, fault distributions, and clustering of particles

    Publication Year: 1986, Page(s):326 - 338
    Cited by:  Papers (97)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (969 KB)

    Increasing the levels of semiconductor integration to larger chips with more transistors causes the fault and defect distributions of VLSI memory chips to deviate increasingly further from simple random Poisson statistics. The spatial distributions of particles on semiconductor wafers have been analyzed to gain insight into the nature of integrated circuit defect statistics. The analysis was done ... View full abstract»

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  • Recent papers by IBM authors

    Publication Year: 1986, Page(s):339 - 348
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (857 KB)

    The information listed here is supplied by the Institute for Scientific Information. Reprints of the papers may be obtained by writing directly to the first author cited. Papers are listed alphabetically by author. View full abstract»

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  • Recent IBM patents

    Publication Year: 1986, Page(s):349 - 352
    IEEE is not the copyright holder of this material | PDF file iconPDF (305 KB)
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IBM T. J. Watson Research Center