304 research outputs found

    Two-dimensional coding for probe recording on magnetic patterned media

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    The effect of intertrack intersymbol interference in a magnetic patterned medium is studied. A two-dimensional (2-D) channel code is proposed, dedicated to perpendicularly magnetized media without soft underlayer, which exhibit read pulses showing overshoot. Read pulse shapes were investigated using a magnetic-force microscope tip scanning the patterned medium row-by-row. To test different codes, a bit-detection simulation program was developed to generate large amounts of data on which bit error rates can be measured. Application of the 2-D channel code, which implies recording of particular dot positions with fixed bits ("ones", "zeros"), resulted in the elimination of 2-D worst-case bit patterns and a subsequent reduction of detected-bit errors. The accompanying redundancy of 22% is inevitable for this type of 2-D code

    Towards compliant data retention with probe storage on patterned media

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    We describe how the compliance requirements for data retention from recent laws such as the US Sarbanes Oxley Act may be supported by a tamper-evident secure storage system based on probe storage with a patterned magnetic medium. This medium supports normal read/write operations by out-of-plane magnetisation of individual dots. We report on an experiment to show that in principle the medium also supports a separate class of write-once operation that destroys the out-of-plane magnetisation property of the dots irreversibly by precise local heating. The write-once operation can be used to support flexible data retention by tamper-evident writing and physical data deletion

    Towards Tamper-Evident Storage on Patterned Media

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    We propose a tamper-evident storage system based on probe storage with a patterned magnetic medium. This medium supports normal read/write operations by out-of-plane magnetisation of individual magnetic dots. We report on measurements showing that in principle the medium also supports a separate class of write-once operation that destroys the out-of-plane magnetisation property of the dots irreversibly by precise local heating. We discuss the main issues of designing a tamper-evident storage device and file system using the properties of the medium

    Field Emission to control nanometer tip-medium distances in probe storage

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    In this work, we present a novel concept for high resolution proximity sending based on field emission and provide more insight in the vacuum conditions and electronics needed for stable operation

    A study of physiological mechanisms and inter-relations between systemic and regional blood volume, blood flow and electrolyte balance Interim progress report, Jun. 30 - Dec. 31, 1967

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    Regulation of sodium excretion in dog, and effects of atrial size and function upon secretion of sodium load - circulatory response to upright til
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