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IEEE Transactions on Magnetics

Issue 4 • Date July 1978

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Displaying Results 1 - 25 of 34
  • [Front cover and table of contents]

    Publication Year: 1978, Page(s): 0
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    Freely Available from IEEE
  • Chairman's notes

    Publication Year: 1978, Page(s): 135
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  • Technical innovations in information storage and retrieval

    Publication Year: 1978, Page(s):143 - 148
    Cited by:  Papers (2)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (455 KB)

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  • A survey of recent advances in magnetic recording materials

    Publication Year: 1978, Page(s):136 - 142
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (848 KB)

    Magnetic recording coatings are still made predominantly of iron oxide particles but the newer particles are significantly better in magnetic properties, dispersibility and orientability than the particles used, say, ten years ago. Chromium dioxide particles show excellent recording performance (particularly at densities above 1000 flux changes per millimeter) but they are presently being challeng... View full abstract»

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  • The disk drive industry

    Publication Year: 1978, Page(s):149 - 153
    Cited by:  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    The size and structure of the moving head rigid disk drive and flexible disk drive industries are analyzed, with historical data and projections covering the span from 1976 to 1980. Products are analyzed in 12 categories, with discussion of underlying factors contributing to the growth or decline of individual product groups. View full abstract»

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  • Magnetic measurements for digital magnetic recording

    Publication Year: 1978, Page(s):154 - 159
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB)

    Common engineering magnetic measurements used in the definition and application of digital recording media are defined along with their relationships to basic magnetic material parameters. The effects of the variation of magnetic material parameters on digital recording performance are discussed. Descriptions are given of the operation and use of φ-H meters and vibrating sample magnetometers.... View full abstract»

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  • Evolution of the minifloppy (TM) product family

    Publication Year: 1978, Page(s):160 - 166
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  • Digital mini-cassette

    Publication Year: 1978, Page(s):167 - 170
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    The development of a new small-sized removable magnetic media product is followed from product inception thru design specification, mathematical modeling performance testing, and field testing. A mathematical model of the mini-cassette was developed to optimize the design for low-power consumption and long life. Portions of this model are discussed. The specific implementation of the design goals ... View full abstract»

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  • An improved ANSI-compatible magnetic tape cartridge

    Publication Year: 1978, Page(s):171 - 175
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    A new tape-winding principle is described, by which winding stress on the web is minimized. Prior art is reviewed, including isoelastic drives and the so-called Newell Principle; advantages of the new drive are given. A typical product is described: an ANSI-compatible 1/4-inch cartridge interchangeable with the 3M DC300A. View full abstract»

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  • Head positioning servo design for the IBM 3344/3350 disk files

    Publication Year: 1978, Page(s):176 - 177
    Cited by:  Papers (4)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    The 3344/3350 disk files have significantly increased both the recording areal density and total storage capacity per spindle in comparison to previous disk file products, such as the 3340. Parameters directly related to the head positioning systems are compared. Three areas of the head positioning servo system that required design changes for increased performance are described: (1) the encoding ... View full abstract»

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  • Beyond the second order system in track following servos

    Publication Year: 1978, Page(s):178 - 181
    Cited by:  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    Voice coil linear actuators are typically characterized as a basic second order system. However, component mechanical resonant frequencies often result in design degradations in the basic second order system. These conditions manifest themselves as possible servo loop instabilities in the frequency domain. This leads to poor static positioning, stiffness and dynamic positioning inaccuracies. This ... View full abstract»

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  • A track locating servo system utilizing the data heads as absolute position transducers

    Publication Year: 1978, Page(s):182 - 184
    Cited by:  Papers (1)  |  Patents (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    Magnetic transitions may be compactly written in the normally unused deadspace between the data sectors on each data surface of a moving head disc drive, which may be read by ordinary data heads to obtain absolute position information for use by the track locating servo. A track following system which complements the track locating system is briefly described. Implementation of these techniques el... View full abstract»

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  • An adaptive filter for the processing of position error signal in disk drives

    Publication Year: 1978, Page(s):185 - 187
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A novel circuit used to process analog position error information in a disk drive head-positioning servo system drastically reduces noise in the signal and compensates for effects due to insufficient position sample rate at high carriage velocities. The processed signal does not suffer from envelope droop at high carriage velocities, and lends itself well to track counting algorithms. Because the ... View full abstract»

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  • Application of thin film head technology to a high performance head/track disk file

    Publication Year: 1978, Page(s):188 - 190
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Processing technologies and performance parameters of thin film recording heads used in a 6.7Mbyte disk memory are presented. Photolithographic, vacuum deposition, and ceramic substrate fabrication procedures are described for a single turn, multi-track head assembly. Interlayer diffusion and thermal heating are described. Data relating spacing loss, bit density, gap geometry, and write currents t... View full abstract»

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  • Data detection methods vs head resolution in digital magnetic recording

    Publication Year: 1978, Page(s):191 - 193
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The detection methods for determining the presence of a magnetically recorded bit depend on the operating conditions of the magnetic recording head and media. The Bit Density curve which best describes the head and media operating conditions is divided into four regions of interest. Methods for data detection suitable for each of the regions are listed together with block diagrams of typical detec... View full abstract»

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  • The relationship between disk surface acceleration and head-to-disk interaction

    Publication Year: 1978, Page(s):194 - 196
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    One dominant trend in magnetic disk recording has been rapidly increasing areal bit density. This has been accompanied by lower head flying heights, which has caused the disk surface smoothness and flatness to be of greater concern. One technique for evaluating the surface is to fly a 3330 type slider equipped with a piezoelectric crystal instead of a read/write head. The output of the piezo-elect... View full abstract»

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  • A technique for measuring pole tip saturation of low inductance heads

    Publication Year: 1978, Page(s):197 - 200
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    Increasing the coercive force of a magnetic recording medium normally improves high density digital performance. However, in rigid disk systems, the head is not in intimate contact with the disk. In addition, the ferrites employed as head materials have much lower saturation magnetization than the metals normally used in other types of heads. Under these conditions, the head field may be inadequat... View full abstract»

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  • A fixed read/write head utilizing Winchester technology

    Publication Year: 1978, Page(s):201 - 202
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    The traditional goal when designing a fixed-head disc is to combine reliability, compactness and low cost. The usual technique of achieving these goals is to use a large slider containing many read/write heads. When recording density is increased, the heads must operate at a lower flying height, and a large slider interferes with the typical disc profile. Data General's 6063 fixed head disc drive ... View full abstract»

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  • Microprocessor applications in disk storage systems

    Publication Year: 1978, Page(s):203 - 206
    Cited by:  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    The implementation of a disk drive using a micro-processor has led to capabilities not previously found in such devices. This paper will give a brief overview of the architecture of the disk drive and the traditional control functions that have been assimilated by the microprocessor. It will then discuss these new capabilities which include autonomous fault diagnosis, independent servo and I/O exe... View full abstract»

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  • On ensuring data recoverability by the use of error-correcting codes

    Publication Year: 1978, Page(s):207 - 209
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    The problem of controlling data errors in magnetic disc storage is one of fundamental importance. Data errors caused by electrical noise within the system are considered 'soft' and generally recoverable by retry of the data transfer operation, resulting in execution overhead. However, errors caused by inherent defects in the recording media or due to contamination are considered to be 'hard' and o... View full abstract»

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  • New stable state of bubbles containing Bloch lines

    Publication Year: 1978, Page(s):210 - 212
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    A new kind of bubble having two stable states for a bias field HBhas been found in thin garnet films. The bubble becomes smaller with increasing HBand disappears abruptly at some critical field H_{C1} . However, it does not collapse at H_{C1} . When HBis lowered, it comes into sight sudde... View full abstract»

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  • An analysis of tilted magnetic transitions in magnetic recording media

    Publication Year: 1978, Page(s):213 - 218
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (504 KB)

    A theoretical analysis of a transition is presented. The centerline of the transition through the media is tilted from the normal to the surface. For an isolated transition, it is shown that both the demagnetizing fields and the readback pulse shape are dependent upon the amount of tilting. For the case of sinusoidal recording, the tilting introduces an additional phase shift and amplitude reducti... View full abstract»

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  • Decision feedback equalization of the dc null in high-density digital magnetic recording

    Publication Year: 1978, Page(s):218 - 222
    Cited by:  Papers (20)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    The dc null in a digital magnetic recording channel is equalized in a novel way which allows recovery of direct recorded NRZ waveforms with no coding constraints. The technique involves decision feedback equalization which can be implemented with simple RC filters. Feedback power is determined by the choice of RC and can b... View full abstract»

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  • A vector model for magnetic hysteresis based on interacting dipoles

    Publication Year: 1978, Page(s):223 - 227
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    A model for magnetic hysteresis is described in which the applied field intensity is free to rotate as well as vary in magnitude. The model is an infinite lattice of ellipsoidal Stoner-Wolfarth particles with N^{3} = 8,27,64,125,216... independent and not necessarily identical particles per unit cell. Techniques for making this simple yet very general model c... View full abstract»

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  • Eddy current induction in a solid conducting cylinder with a transverse magnetic field

    Publication Year: 1978, Page(s):227 - 232
    Cited by:  Papers (24)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Quasistatic magnetic field solutions for a right circular cylinder of arbitrary conductivity and permeability immersed in a uniform transverse magnetic field are considered. The cases of a rotating cylinder in a dc magnetic field and a stationary cylinder in an ac magnetic field are included. The solutions are described in terms of the magnetic Reynolds number, a dimensionless quantity which indic... View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology