Abstract: An acceleration sensor outputs a signal in accordance with acceleration. A differentiator outputs a differential signal of the output signal. A comparator inverts the state of an output when the differential signal goes beyond a threshold. A monostable multivibrator maintains the state-inverted signal of the output for a predetermined period of time. An integrator integrates the acceleration detection signal. A comparator inverts the state of an output signal when an integrated signal goes beyond a threshold. A fall determination processor outputs a signal out indicating that a fall has been detected in a situation in which, when the output of the monostable multivibrator is active, the state of the output of the comparator is inverted.

Abstract: A disk drive includes a disk comprising a plurality of zones, a clock for generating a timing signal having a timing frequency, a voltage controller for providing a supply voltage, and circuitry coupled to the supply voltage and responsive to the timing frequency. Power may be conserved by receiving a host command; selecting one of the plurality of zones based on the host command; and adjusting the timing frequency and the supply voltage provided to the circuitry based at least in part on the selected zone.

Abstract: Embodiments of the present invention provide a magnetic disk drive system in which the write element leads the read element in the tangential direction of rotation of the magnetic disk. In addition, the servo sector information is preferably arranged such that information that is not needed for write operation is placed at the end of the servo sector. In this way, the servo read operation can be terminated sooner and the write operation can initiate sooner after going over the servo sector. The write element in a write operation writes data to the data sector of a track until an end of the data sector before reaching a front end of a servo sector following the end of the data sector. The read element reads information in the servo sector needed for the write operation. The write element starts writing data in a next data sector following the servo sector after the write element reaches the next data sector and after the read element has read all information in the servo sector needed for the write operation.

Abstract: Systems and techniques relating to interpreting signals on a channel having an asymmetrical signal amplitude response. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, includes an asymmetry correction circuit configured to receive an analog signal and to compensate for asymmetry in the received analog signal, a signal equalizer configured to receive an input signal responsive to an output of the asymmetry correction circuit and to generate an equalized signal, a discrete time sequence detector operable to examine the equalized signal, and a control circuit that provides a coefficient adjustment to the asymmetry correction circuit to affect the asymmetry compensation based on an estimate of non-linearity derived from the equalized signal and an output of the discrete time sequence detector. The estimate can be a least mean squared estimate of the non-linearity in the equalized signal.

Abstract: A media event timer includes a counter module for generating a sequence of counts based on a clock signal of a disk drive unit. A counter reset module sets the counter module to a reset count in response to a servo address mark detection signal. A detector module detects that a servo address mark has been missed and sets the counter module to a restart count when the servo address mark has been missed. A trigger module triggers a first media event when a first media event count compares favorably to a count of the sequence of counts.

Abstract: An apparatus including a cantilevered head assembly is disclosed. The apparatus includes a flow control device to control flow proximate to the cantilevered head assembly. In one embodiment, the flow control device includes a blower assembly coupleable to a pressure source and/or vacuum assembly to limit flow disturbances proximate to the cantilevered head assembly.

Abstract: A method for writing data in a tape drive is provided by the present invention. The present invention provides a method for writing data in a tape drive. The invention include allocating a blank area for transpose writing on a magnetic tap and then writing a first group of data sets on the magnetic tape adjacent to the blank area. The tape drive maintains full operating speed during intervals between writing successive data sets, resulting in spaces between the data sets. At a specified interval, the drive repositions the tape writes a transposed data block to the allocated blank area, wherein the transposed data block contains the same content as the first group of data sets. A new blank area for transpose writing is then allocated adjacent to the recently transposed data block.

Abstract: Disclosed are a method and system for distinguishing spatial and thermal defects on perpendicular media. The magnetic domains of the perpendicular media are oriented to have a first polarity, scanned using a read head, oriented to have a second polarity and scanned again. The signals from the read head are combined to produce output signals having improved signal to noise ratios from which the locations of spatial and thermal defects can be identified and distinguished.

Abstract: The present invention provides a master disk for magnetic transfer which has a disk-like outer shape and in the surface of which a large number of fine magnetic layer patterns are formed, wherein the relationship between the outside diameter size d (mm) of the extreme outer circumference of the magnetic layer pattern and the master disk thickness t (mm) is given by 2.04×10?3×d+0.006?t?8.15×10?3×d+0.024, in order to exclude the effects of bows, strains and thickness deviations of a master disk in performing magnetic transfer and ensure that accurate transfer of magnetization patterns can be performed.

Abstract: A recording and reproducing apparatus includes: a recording section for recording an information signal in a magnetic recording medium including a magnetic layer including hexagonal ferrite; a reproducing section for reproducing the information signal recorded in the magnetic recording medium, the reproducing section including: a reproducing head for reading the information signal from the magnetic recording medium; an equalizer for equalizing the information signal read from the magnetic recording medium, wherein a partial response of the information signal after equalization by the equalizer satisfies a condition that 0.4?a<3.0, ?0.6?b<2.0, ?2.0<c??0.2, ?3.0<d??0.4, and ?1.0<e?0.0. A corresponding reproducing method, a corresponding reproducing apparatus, and the magnetic recording medium are also disclosed.

Abstract: A method, and system configured to implement the method, are provided. The method includes the steps of identifying a last usable track on a surface as a function of a parameter, and defining a standoff band of tracks relative to the last usable track to obtain an achieved maximum track on the surface. The last usable track is, in exemplary embodiments, a track beyond a default maximum track on a surface of a data storage medium.

Abstract: Methods and systems for sensing a position of a transducer head with respect to a storage medium. One method includes generating a read signal from a servo track stored on a magnetic storage medium. The servo track includes servo frames of magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle and a mid-frame synchronization mark incorporated within the tone field, wherein the tone field provides a metric reference for dimensional measurements between features within the servo frame(s). The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.

Abstract: A medium storage device writes or read data on a storage medium synchronizing the rotation of the storage medium with the DSW method for decreasing the gap length considering the rotation jitter. The medium storage device has a controller for generating synchronization timing signals during reading/writing from a clock, and a processing unit for calculating the correction value of the frequency from the measurement result of the servo synchronization mark space of the storage medium. The processing unit judges whether the servo synchronization mark has been correctly detected and calculates the frequency correction value. Therefore changing the synchronization timing using the SSM interval detected in error can be prevented, and the danger of data corruption can be avoided.

Abstract: Methods and systems for sensing a position of a transducer head with respect to a storage medium. One method includes generating a read signal from a servo track stored on a magnetic storage medium. The servo track includes servo frames of magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle and a mid-frame synchronization mark incorporated within the tone field, wherein the tone field provides a metric reference for dimensional measurements between features within the servo frame(s). The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.

Abstract: A technique for de-gaussing the pole tips and yoke of a write transducer in a perpendicular magnetic recording system is provided. An oscillator in the read channel is configured to produce an adjustable signal pattern output to the preamplifier when a write operation ends for a given time and at a predetermined frequency, such that as the preamplifier write current decays, it decays with transitions (polarity reversals). This results in a decaying AC field being applied to the write transducer at the end of a media write operation, effectively de-gaussing it and reducing the effects of remanent magnetization remaining in the poles and yoke of the magnetic recording head after a write current is turned off. This defeats a potential pole tip lockup or yoke lockup circumstance in the magnetic recording media which can result in an inability to write further data or a possible erasure of valid data on the hard disk with which the write head is associated.

Abstract: Systems and techniques relating to interpreting signals on a channel having an asymmetrical signal amplitude response. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, includes an asymmetry correction circuit configured to receive an analog signal and to compensate for asymmetry in the received analog signal, a signal equalizer configured to receive an input signal responsive to an output of the asymmetry correction circuit and to generate an equalized signal, a discrete time sequence detector operable to examine the equalized signal, and a control circuit operable to provide a coefficient adjustment to the asymmetry correction circuit to affect the asymmetry compensation based on an estimate of nonlinearity derived from the equalized signal and multiple output values of the discrete time sequence detector, the multiple output values being values corresponding to at least two different discrete times.

Abstract: A disk drive clock circuit includes a servo clock generator and a disk locked frequency converter. The servo clock generator generates a servo clock signal in response to servo information read from a data storage disk in a disk drive. The disk locked frequency converter responds to the servo clock signal by generating a modified clock signal having a different frequency, and adjusts timing of an edge of the modified clock signal in response to a timing event identified from the servo information read from the disk. The disk locked frequency converter can include a divide-by-n counter that is configured to divide the frequency of the servo clock signal by a number n to generate the modified clock signal. The disk locked frequency converter can reset the divide-by-n counter to a defined value in response to the timing event. The modified clock signal can thereby be phase locked to the servo information on the disk.

Abstract: A recording system, such as a magnetic or optical recording system, employs an address mark (AM) detector that searches for an address mark pattern that is augmented by one or more bits of a preamble field so that a false detection rate is reduced. In one case, the address mark includes L bits, and the AM detector compares i) the input detected bits with ii) a SAM pattern of L bits augmented with m bits of the preamble to detect the SAM. In another case, the address mark includes less than L bits (e.g., L?k bits), and the AM detector compares i) the input detected bits with ii) a SAM bit-pattern of (L?k) bits augmented with m bits of the preamble to detect the SAM.

Abstract: Interpreting signals on a noisy channel with polarity uncertainty. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, includes a first detector (e.g., a Viterbi detector) responsive to a readback signal and operable to examine the readback signal at alternative framings based on possible signal polarities of the readback signal, and a second detector (e.g., a servo field detector) responsive to an output of the first detector and operable to find a data pattern that indicates control information (e.g., a servo address mark) in the readback signal and to determine a signal polarity of the readback signal by comparing signal quality information corresponding to the possible signal polarities of the readback signal.

Abstract: A magnetic data read circuit includes a differentiation circuit and an integration circuit which are individually connected to a magnetic head, and a means of read judgment for pass/fail judgment on reading operation of magnetic data detected at the magnetic head. The read judgment means has first and second storage sections in which data relating to an output signal of the differentiation circuit and the integration circuit, respectively, are stored. The read judgment section obtains data from at least one of the first storage section and the second storage section and makes a pass/fail judgment on reading operation of the magnetic data. Such a magnetic data read circuit improves accuracy of reading magnetic data stored in a magnetic recording medium from a single transfer of the magnetic recording medium data.