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IBM Journal of Research and Development

Issue 6 • Date Nov. 1974

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Displaying Results 1 - 21 of 21
  • Preface

    Publication Year: 1974, Page(s): 479
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (204 KB)

    This issue contains a group of papers on a wide range of research and development topics in magnetic recording. These papers, rather than being the outgrowth of a single development program, report new and innovative results from the various disciplines in disk file and tape file technologies. View full abstract»

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  • Aerodynamic Aspects of Disk Files

    Publication Year: 1974, Page(s):480 - 488
    Cited by:  Papers (25)  |  Patents (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (902 KB)

    Airflows between centrally clamped, rotating, rigid disks are investigated with respect to the type of flow pattern, the parameters that influence nonuniform flow, and the effects of various flow patterns on disk stability. The experimental method uses a water-flow modeling technique for the airflow. The observed flow patterns are highly unsteady. The configuration and position of the shroud and s... View full abstract»

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  • Engineering Design of a Disk Storage Facility with Data Modules

    Publication Year: 1974, Page(s):489 - 505
    Cited by:  Papers (13)  |  Patents (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1398 KB)

    The design of the IBM 3340 Direct Access Storage Facility with IBM 3348 Data Modules incorporates new concepts and required the development of several innovative components, including newly designed magnetic read-write heads. The heads start and stop in contact with the disk and use a tri-rail, air-bearing slider having a low mass. Each data module includes read-write heads, a head carriage, disks... View full abstract»

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  • Design of a Disk File Head-Positioning Servo

    Publication Year: 1974, Page(s):506 - 512
    Cited by:  Papers (24)  |  Patents (36)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (615 KB)

    The engineering design of a head-positioning system for an interchangeable-medium disk file is considered. Emphasis is placed upon three specific functions within the positioning system: (1) encoding and demodulation of information from the dedicated servo surface, (2) compensation and dynamics of the track-following control system, and (3) implementation of control electronics for a quasi-time-op... View full abstract»

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  • Dynamic Response of Self-acting Foil Bearings

    Publication Year: 1974, Page(s):513 - 520
    Cited by:  Papers (9)  |  Patents (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (744 KB)

    A new approach to the analysis of wide foil bearings is investigated. The equation of motion for a finite length of tape is coupled to the transient lubrication equation for the air film between the tape and the recording head. Compressibility and slip flow are retained in the fluid mechanics equation; flexural rigidity and high-speed dynamic effects are retained in the tape equation. The steady-s... View full abstract»

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  • White Light Interferometry of Elastohydrodynamic Lubrication of Foil Bearings

    Publication Year: 1974, Page(s):521 - 528
    Cited by:  Papers (1)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (737 KB)

    This paper describes an experiment performed to verify the one-dimensional model of elastic foil behavior developed by Stahl, White, and Deckert. In the experiment, a loop of tape one-inch wide passes over a stationary recording head, and the air-film thickness between the head and the foil is determined using white light interferometry. Measured data for various experimental conditions are compar... View full abstract»

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  • Infrared Laser Interferometer for Measuring Air-bearing Separation

    Publication Year: 1974, Page(s):529 - 533
    Cited by:  Papers (12)  |  Patents (10)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (572 KB)

    The design and characteristics are presented for an infrared instrument capable of measuring air-bearing separation distances over a mechanical bandwidth ranging from dc to 30 kHz. The measurement technique involves monitoring optical intensity variations of the interferometric cavity formed by two air-bearing surfaces. This intensity varies between a minimum at zero separation and a maximum at a ... View full abstract»

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  • Transition from Boundary Lubrication to Hydrodynamic Lubrication of Slider Bearings

    Publication Year: 1974, Page(s):534 - 540
    Cited by:  Papers (13)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (646 KB)

    The transition from boundary lubrication to fully hydrodynamic lubrication is investigated for air-lubricated slider bearings using the electrical resistance method. Intermittent contacts are shown to exist even under conditions for which the numerical solution of the Reynolds equation or white light interferometry predicts steady state spacings in the spacing region from 0.125 to 0.25 µm. ... View full abstract»

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  • Hand-held Magnetoresistive Transducer

    Publication Year: 1974, Page(s):541 - 546
    Cited by:  Papers (8)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (655 KB)

    The initial design of a vertical magnetoresistive head in a hand-held wand for reading magnetically encoded price tags and credit cards is discussed. The performance of the head (e.g., resolution, signal shape and amplitude, and signal-to-noise ratio) is analytically and experimentally evaluated as a function of the configuration of the sensor, head-to-medium interface, and sensor processing and m... View full abstract»

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  • Thermally Induced Pulses in Magnetoresistive Heads

    Publication Year: 1974, Page(s):547 - 550
    Cited by:  Papers (21)  |  Patents (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (582 KB)

    The thermal response of a magnetoresistive head is analyzed for frictional heating between the head surface and dust particles or other asperities on the recording medium surface during relative motion of head and medium. A theoretical model is presented showing that pulses are induced in the output of a magnetoresistive head as a result of this frictional heating. The model predicts the dependenc... View full abstract»

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  • Numerical Analysis of the Shielded Magnetoresistive Head

    Publication Year: 1974, Page(s):551 - 555
    Cited by:  Papers (11)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (499 KB)

    Numerical computations for the shielded magnetoresistive head are reported and compared with previous analytic and experimental results. Linear resolution is found to be essentially the same as for inductive heads. Output amplitude is in the range 50 to 175 V per meter track width for a sense current density of 5 × 1010 A/m2. View full abstract»

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  • Ferrite Film Recording Surfaces for Disk Recording

    Publication Year: 1974, Page(s):556 - 562
    Cited by:  Papers (8)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (656 KB)

    Ferrite thin films have been prepared using a chemical deposition process; hematite and substituted hematite films were formed by spin coating a diluted solution of the metal nitrates on a substrate and subsequently heating the substrate in air to 300°C to crystallize the film. Magnetic ferrite films were formed by reducing the films in a wet hydrogen atmosphere. Process parameters, which h... View full abstract»

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  • The Remanent State of Recorded Tapes

    Publication Year: 1974, Page(s):563 - 569
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (627 KB)

    Measurements are reported on the in-plane and the perpendicular components of the remanence a tape acquires on passing through the steady field of a recording head. The tape coatings were oriented and unoriented particles of γ-Fe2O3, oriented CrO2 and unoriented Co-substituted γ-Fe2O3. The two writing heads used had 10 µm-... View full abstract»

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  • Noise in Disk Data-recording Media

    Publication Year: 1974, Page(s):570 - 575
    Cited by:  Papers (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (570 KB)

    Measurements were made of recording medium noise in erased disks using an in-contact magnetoresistive element and an inductive head supported on an air bearing slider. Four types of coatings on aluminum disks were examined: thin, transition-metal alloy film, CrO2, FeCo particle, and γ-Fe2O3. Results obtained by means of three measurement techniques are in qu... View full abstract»

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  • Switching Speeds in Magnetic Tapes

    Publication Year: 1974, Page(s):576 - 578
    Cited by:  Papers (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (408 KB)

    Comparative measurements are reported on the switching speeds of three different magnetic tape materials, as determined by application of short field pulses of well-defined duration and magnitude. A sensitive measure of the change in magnetization is the length of applied pulse required for the peak readback signal to drop from 60 percent to 40 percent of its peak value. This pulse length was 2.6 ... View full abstract»

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  • Optimal Rectangular Code for High Density Magnetic Tapes

    Publication Year: 1974, Page(s):579 - 588
    Cited by:  Papers (16)  |  Patents (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1264 KB)

    IBM's 6250 bpi 3420 series tape units require a powerful error-correcting code for the standard 9-track format. The optimal rectangular code (ORC), presented here, is designed to correct any single-track error or, given erasure pointers, any double-track error in the tape. The code achieves this by conforming to a rectangular codeword of which two orthogonal sides are check bits. The code is speci... View full abstract»

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  • Recent papers by IBM authors

    Publication Year: 1974, Page(s):589 - 592
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (490 KB)

    Reprints of the papers listed here can usually be obtained by writing directly to the authors. The authors' IBM divisions are identified as follows: ASDD is the Advanced Systems Development Division; DPD, Data Processing Division; FED, Field Engineering Division; FSD, Federal Systems Division; GPD, General Products Division; GSD, General Systems Division; OPD, Office Products Division; RES, Resear... View full abstract»

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  • Recent IBM patents

    Publication Year: 1974, Page(s):593 - 595
    IEEE is not the copyright holder of this material | PDF file iconPDF (365 KB)
    Freely Available from IEEE
  • Author Index for papers Volume 18

    Publication Year: 1974, Page(s):601 - 602
    IEEE is not the copyright holder of this material | PDF file iconPDF (283 KB)
    Freely Available from IEEE
  • Subject Index for papers Volume 18

    Publication Year: 1974, Page(s):603 - 604
    IEEE is not the copyright holder of this material | PDF file iconPDF (268 KB)
    Freely Available from IEEE
  • Contents of previous issue

    Publication Year: 1974, Page(s): 605
    IEEE is not the copyright holder of this material | PDF file iconPDF (204 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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Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center