Download or read book Signal Processing for Bit patterned Media Recording and Heat assisted Magnetic Recording with Media Noise written by Yibin Ng and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coding and Signal Processing for Magnetic Recording Systems written by Bane Vasic and published by CRC Press. This book was released on 2004-11-09 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implementing new architectures and designs for the magnetic recording read channel have been pushed to the limits of modern integrated circuit manufacturing technology. This book reviews advanced coding and signal processing techniques and architectures for magnetic recording systems. Beginning with the basic principles, it examines read/write operations, data organization, head positioning, sensing, timing recovery, data detection, and error correction. It also provides an in-depth treatment of all recording channel subsystems inside a read channel and hard disk drive controller. The final section reviews new trends in coding, particularly emerging codes for recording channels.
Download or read book Signal Processing for Two Dimensional Magnetic Recording written by Anantha Raman Krishnan and published by . This book was released on 2011 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: With magnetic storage devices already achieving storage densities of up to 400 Gigabits per square inch (Gb/in2), the state of the art is rapidly approaching theoretical limits (dictated by thermal stability concerns). Hence, there is an eort in the industry to develop alternative magnetic storage technologies. Two-dimensional magnetic recording (TDMR) is one such candidate technology. In contrast to other technologies(e.g. heat-assisted magnetic recording [1], bit-patterned media [2]) which rely on signicant changes being made to the recording medium, TDMR relies on the use of traditional recording media, while relying on signal processing to make improvements in the recording density. Though advantageous due to the fact that no drastic re-engineering of media is required, there are signicant challenges that need to be addressed in order to make TDMR a viable candidate for next-generation recordingsystems. The main challenges involved in TDMR arise due to (i) the small bit-area, along with an aggressive write/read process, which leads to a large amount of noise, and (ii) the two-dimensional nature of the recording process { so far not encountered in today's systems. Thus, a gamut of 2D signal processing algorithms need be developed for the compensation of errors occurring due to the aggressive write/read processes. In this dissertation, we present some of the work done with regard to the signal processing tasks involved in TDMR. In particular, we describe our work on (i) channel modelling, (ii) detection strategies, and (iii) error-correction coding strategies targetted at TDMR.
Download or read book Acoustically Assisted Magnetic Recording written by Weiyang Li and published by . This book was released on 2015 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past few decades, magnetic recording has been used as a dominant solution for massive data storage due to its large capacity, excellent reliability and low cost. Nowadays, exponentially increasing user-generated information is creating a huge demand as well as great challenges for high density data storage solutions. For high density magnetic recording, or more specifically, for hard disk drives, the bit size of the recording medium has to be reduced. This requires the medium to have an increased coercivity to avoid data loss due to thermal instability. However, data recording in a high coercivity medium is challenging due to the limited practicable write field. Therefore, the requirements of high coercivity for data stability and low coercivity for writeability are conflicting. During the last 15 years, enormous research and engineering efforts have been invested in heat-assisted magnetic recording and bit-patterned media, endeavoring to solve this contradiction. In this dissertation we take an alternative approach and demonstrate that acoustic wave, or strain wave, could be used to address the tradeoff between writeability and stability. This technique is called acoustically assisted magnetic recording. The physics behind this technique is based on the inverse magnetostriction effect or Villari effect, by which the coercivity of a magnetostrictive material can be modified by strain. In operation, a surface acoustic wave is applied to a recording medium, where the resulting acoustic strain temporarily lowers the coercivity (thus makes it magnetically soft), enabling data to be recorded with a lower write field. The medium regains its high coercivity after the acoustic wave is removed and thus becomes magnetically hard for data stability. An experimental device consisting of an interdigitated transducer is designed and fabricated on a piezoelectric quartz substrate for generating the surface acoustic wave. Galfenol film with high magnetostriction is deposited as the recording medium on the same substrate. The acoustic wave propagates in the galfenol film and the resulting strain is measured by laser interferometry. In the proof-of-principle experiments for acoustically assisted magnetic recording, data are recorded in a strained magnetostrictive medium with a smaller write field than when it is unstrained. The required write field strength is lowered by ~10% with ~100 ppm strain applied to the medium. A curved acoustic transducer is developed to focus the acoustic strain so large change in coercivity can be achieved in the focal spot and to demonstrate that an individual bit can be selectively written in the medium. In hard disk drives, rather than the low coercivity galfenol film, high coercivity material is used as the recording medium. L10 phase Fe50Pt(50-x)Pdx thin film is a promising candidate for next-generation high coercivity recording media and its magnetostriction is characterized regarding to the application of acoustically assisted magnetic recording. It is found that the magnetostriction of Fe50Pt(50-x)Pdx film is dependent on the Pd content. This suggests that the magnetostriction can be controlled and thus optimized by adjusting the film composition. Also, to apply the acoustically assisted magnetic recording technique to the practical hard disk drives, the acoustic transducer should be integrated in the write head and the generated acoustic wave needs to be air coupled from the head to the recording medium. An electromagnetic acoustic transducer is developed to investigate the possibility of coupling the wave through electromagnetic interaction. The investigation of mechanical-magnetic interaction between acoustic waves and magnetostrictive films also leads to applications other than magnetic recording. We demonstrate that various and controllable magnetization patterns such as periodic stripes (10 [micro]m periodicity) and single dot (3 [micro]m diameter) could be written in the magnetostrictive film by creating different acoustic interferences. This could be potentially used in magnetic particle manipulation, spatial light modulation and magnonic signal processing. Also, a surface acoustic wave magnetic field sensor using galfenol thin film is successfully demonstrated. Here, based on the [delta]E effect, the velocity of acoustic wave propagating in the galfenol film is measured to determine the magnetic field. Since galfenol is highly magnetostrictive, a maximum velocity change of 6.4% is achieved, much larger than previously reported results in similar systems.
Download or read book Noise In Digital Magnetic Recording written by Thomas C Arnoldussen and published by World Scientific. This book was released on 1992-04-30 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book treats the various aspects of noise from magnetic recording media and the impact on system performance. Several authors present discussions of: materials and processes used to fabricate media for computer data storage, theoretical aspects of noise and micromagnetic behavior, experimental methods and characterization, and system analysis. In the past decade thin film recording media have largely displaced particlate media in rigid disk recording systems. During the same period of time the field has evolved from the prevalent belief that thin film media were virtually noiseless to a detailed understanding of the origin and the manifestation of noise in these new media. This understanding has lead to the ability to make the very low noise media needed in present applications. The present state of understanding of both particulate and thin film media is summarized.
Download or read book Advanced Signal Processing for Magnetic Recording on Perpendicularly Magnetized Media written by Wu Chang and published by . This book was released on 2010 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of Magnetic Recording written by H. Neal Bertram and published by Cambridge University Press. This book was released on 1994-03-17 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive text on the theory of the magnetic recording process.
Download or read book Sputtering Materials for VLSI and Thin Film Devices written by Jaydeep Sarkar and published by William Andrew. This book was released on 2010-12-13 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important resource for students, engineers and researchers working in the area of thin film deposition using physical vapor deposition (e.g. sputtering) for semiconductor, liquid crystal displays, high density recording media and photovoltaic device (e.g. thin film solar cell) manufacturing. This book also reviews microelectronics industry topics such as history of inventions and technology trends, recent developments in sputtering technologies, manufacturing steps that require sputtering of thin films, the properties of thin films and the role of sputtering target performance on overall productivity of various processes. Two unique chapters of this book deal with productivity and troubleshooting issues. The content of the book has been divided into two sections: (a) the first section (Chapter 1 to Chapter 3) has been prepared for the readers from a range of disciplines (e.g. electrical, chemical, chemistry, physics) trying to get an insight into use of sputtered films in various devices (e.g. semiconductor, display, photovoltaic, data storage), basic of sputtering and performance of sputtering target in relation to productivity, and (b) the second section (Chapter 4 to Chapter 8) has been prepared for readers who already have background knowledge of sputter deposition of thin films, materials science principles and interested in the details of sputtering target manufacturing methods, sputtering behavior and thin film properties specific to semiconductor, liquid crystal display, photovoltaic and magnetic data storage applications. In Chapters 5 to 8, a general structure has been used, i.e. a description of the applications of sputtered thin films, sputtering target manufacturing methods (including flow charts), sputtering behavior of targets (e.g. current - voltage relationship, deposition rate) and thin film properties (e.g. microstructure, stresses, electrical properties, in-film particles). While discussing these topics, attempts have been made to include examples from the actual commercial processes to highlight the increased complexity of the commercial processes with the growth of advanced technologies. In addition to personnel working in industry setting, university researchers with advanced knowledge of sputtering would also find discussion of such topics (e.g. attributes of target design, chamber design, target microstructure, sputter surface characteristics, various troubleshooting issues) useful. . Unique coverage of sputtering target manufacturing methods in the light of semiconductor, displays, data storage and photovoltaic industry requirements Practical information on technology trends, role of sputtering and major OEMs Discussion on properties of a wide variety of thin films which include silicides, conductors, diffusion barriers, transparent conducting oxides, magnetic films etc. Practical case-studies on target performance and troubleshooting Essential technological information for students, engineers and scientists working in the semiconductor, display, data storage and photovoltaic industry
Download or read book Cache and Memory Hierarchy Design written by Steven A. Przybylski and published by Morgan Kaufmann. This book was released on 1990 with total page 1017 pages. Available in PDF, EPUB and Kindle. Book excerpt: A widely read and authoritative book for hardware and software designers. This innovative book exposes the characteristics of performance-optimal single- and multi-level cache hierarchies by approaching the cache design process through the novel perspective of minimizing execution time.
Download or read book A Digital Equalizer for High speed Magnetic Recording written by Kevin D. Fisher and published by . This book was released on 1991 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Channel Modeling to Signal Processing for Bit Patterned Media Recording written by Seyhan Karakulak and published by . This book was released on 2010 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bit-patterned media (BPM) recording is one method proposed to overcome the density limitations imposed by the superparamagnetic effect in continuous recording media. Channel modeling, equalization, and detection aspects of BPM recording are studied in this dissertation. In BPM recording, each bit is recorded on a single domain ``island.'' A read channel model for BPM recording is introduced where the signal contribution from each island is evaluated. Intersymbol interference (ISI) and inter-track interference (ITI) are observed in the model due to the considered head/media geometries. The noise that arises from write/read electronics is modeled by additive white Gaussian noise (AWGN). In the model, the main component of the media noise, which is called ``island jitter'', is assumed to arise from the location fluctuations of islands. Island position shift in the down- track and cross-track directions is modeled with two independent Gaussian random variables. It has been shown that the jitter-induced readback voltage is non-Gaussian. Therefore, higher order approximation for the jitter-induced readback voltage is more accurate in terms of capturing the statistical properties of this noise source. Schemes that utilize different equalization and detection methods are compared for BPM recording channels. A maximum-likelihood (ML) bit sequence detector using the Viterbi algorithm with the modified branch metric is presented for a special case of a symmetric channel response matrix. Joint-track equalization was introduced in the literature before in the context of a single interfering track. A scheme is proposed which utilizes joint-track equalization followed by a Viterbi detector for BPM recording channels. For certain recording densities, simulation results show that the performance of this scheme is comparable to that of the much more complex schemes utilizing optimal bit detection or optimal symbol sequence detection. The proposed scheme also outperforms another scheme of the same complexity introduced in the literature. A parametric study of ITI for BPM recording channel is presented. A surprising phenomenon is observed in the performance curves of optimal bit detectors : The detector performance improved for a certain range of increasing ITI levels for channels both with and without ISI and in the absence as well as in the presence of track misregistration (TMR). For the no-ISI case, this behavior is explained by means of an exact probability of error analysis for the maximum a posteriori (MAP) bit detector, i.e. optimal bit detector. An error event analysis of a punctured ML joint-track detector is used to understand the observed effects of ITI on system performance for channels with ISI.
Download or read book Advances in Modeling and Signal Processing for Bit patterned Magnetic Recording Channels with Written in Errors written by Rodney C. Keele and published by . This book was released on 2012 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Nanoscale Optics and Electronics written by and published by Academic Press. This book was released on 2010-05-25 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing demand for smaller, faster, and more highly integrated optical and electronic devices, as well as extremely sensitive detectors for biomedical and environmental applications, a field called nano-optics or nano-photonics/electronics is emerging – studying the many promising optical properties of nanostructures. Like nanotechnology itself, it is a rapidly evolving and changing field – but because of strong research activity in optical communication and related devices, combined with the intensive work on nanotechnology, nano-optics is shaping up fast to be a field with a promising future. This book serves as a one-stop review of modern nano-optical/photonic and nano-electronic techniques, applications, and developments. Provides overview of the field of Nano-optics/photonics and electronics, detailing practical examples of photonic technology in a wide range of applications Discusses photonic systems and devices with mathematical rigor precise enough for design purposes A one-stop review of modern nano-optical/photonic and nano-electronic techniques, applications, and developments.
Download or read book Introduction to Magnetism and Magnetic Materials written by David Jiles and published by CRC Press. This book was released on 2015-09-18 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: A long overdue update, this edition of Introduction to Magnetism and Magnetic Materials is a complete revision of its predecessor. While it provides relatively minor updates to the first two sections, the third section contains vast updates to reflect the enormous progress made in applications in the past 15 years, particularly in magnetic recordin
Download or read book Developments in Data Storage written by S. N. Piramanayagam and published by John Wiley & Sons. This book was released on 2011-11-08 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: A timely text on the recent developments in data storage, from a materials perspective Ever-increasing amounts of data storage on hard disk have been made possible largely due to the immense technological advances in the field of data storage materials. Developments in Data Storage: Materials Perspective covers the recent progress and developments in recording technologies, including the emerging non-volatile memory, which could potentially become storage technologies of the future. Featuring contributions from experts around the globe, this book provides engineers and graduate students in materials science and electrical engineering a solid foundation for grasping the subject. The book begins with the basics of magnetism and recording technology, setting the stage for the following chapters on existing methods and related research topics. These chapters focus on perpendicular recording media to underscore the current trend of hard disk media; read sensors, with descriptions of their fundamental principles and challenges; and write head, which addresses the advanced concepts for writing data in magnetic recording. Two chapters are devoted to the highly challenging area in hard disk drives of tribology, which deals with reliability, corrosion, and wear-resistance of the head and media. Next, the book provides an overview of the emerging technologies, such as heat-assisted magnetic recording and bit-patterned media recording. Non-volatile memory has emerged as a promising alternative storage option for certain device applications; two chapters are dedicated to non-volatile memory technologies such as the phase-change and the magnetic random access memories. With a strong focus on the fundamentals along with an overview of research topics, Developments in Data Storage is an ideal reference for graduate students or beginners in the field of magnetic recording. It also serves as an invaluable reference for future storage technologies including non-volatile memories.
Download or read book Media Fabrication and Characterization Systems for Three Dimensional multilevel Magnetic Recording written by Nissim Amos and published by . This book was released on 2008 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The data storage industry recently substituted its five-decade-old technology (longitudinal magnetic recording), which reached its fundamental limitations due to thermal instabilities in the recording media, with perpendicular magnetic recording. Nonetheless, the lifetime of this newly adopted technology and other next generation alternatives including heat-assisted magnetic recording (HAMR) and bit patterned media (BPM) is comparably short. In order to defer the superparamagnetic limit substantially beyond 1 Tbits/in 2, it may be necessary to stack information in a third (vertical) dimension.
