Abstract: A reproduction signal evaluation method according to the present invention includes a step of generating a binary signal from an information recording medium on which a data sequence including marks and spaces in combination is recordable, using a PRML signal processing method from a signal obtained by reproducing the data sequence; and a differential calculation step of calculating a differential metric using a first state transition path having a maximum likelihood and a second state transition path having a second maximum likelihood, and a reproduction signal, the first state transition path and the second state transition path being obtained based on the binary signal.

Abstract: A signal pattern detecting apparatus, which is capable of detecting a physical mark in a read back signal being read from an optical disc, includes a matching signal generator, a signal comparing device, and a decision circuit. The matching signal generator is utilized for generating a matching signal, capable of being utilized to identify the physical mark, according to a reference clock and a wobble clock. The signal comparing device is electrically connected to the matching signal generator, and utilized for comparing the matching signal with a wobble data signal to generate a comparison signal. The decision circuit is electrically connected to the signal comparing device, and utilized for generating an indication signal according to the comparison signal and a threshold value. Both the wobble data signal and the wobble clock are derived from the read back signal.

Abstract: The present invention is a device for detecting short burst errors. The device includes a first signal input, wherein the first signal input is configured to receive a first signal. The device includes a second signal input, wherein the second signal input is configured to receive a second signal. The device includes a logic gate, wherein the logic gate is operable for receiving the first signal vial the first signal input, receiving the second signal via the second signal input, and generating a logic output gate signal based on the received first signal and the second signal. Furthermore, the device includes a filter, wherein the filter is configured for receiving the logic output gate signal from the logic gate and generates a filter output signal based upon the received logic output gate signal, wherein the filter output signal is operable for flagging errors.

Abstract: A system reads data from a magnetic storage media. A read head reads data from the magnetic storage media and produce an analog signal. A variable gain amplifier amplifies the analog signal. An offset adjust module substantially centers the amplified analog signal to a midscale. A Magneto Resistive Asymmetry (MRA) correction module MRA corrects the amplified analog signal. A Continuous Time Filter (CTF) compensation module processes the amplified analog signal. An Analog to Digital Converter (ADC) samples the amplified analog signal based upon a control signal to produce a digital signal. A Disk Lock Clock (DLC) system produces the control signal to the ADC. The control signal is representative of a frequency offset caused by at least one servo wedge rate error. A Finite Impulse Response (FIR) filter module filters the digital signal. A sequence detector processes the digital signal and detects a bit sequence from the digital signal.

Abstract: In response to the trend toward the increase in the number of data layers of optical discs, the invention provides a data erasure method and its optical disc apparatus that enable faster data erasures with a simpler configuration. Test erasures are performed on the test areas T of data layers of an optical disc while the power level Pe of data erasure laser light and the defocus amount ?f of the data erasure laser light from a target data layer are changed. Based on the results of the test erasures, the optimal erasure condition that enables a simultaneous data erasure from the greatest number of data layers is determined. Based on the determined optimal erasure condition, then, the optimal erasure sequence that enables data erasure from all of the data layers with the fewest number of times is determined.

Abstract: A defect generated during a nano-imprint process is inspected by a scatterometry method. The scatterometry method is to illuminate the surface of a medium with light having a plurality of wave lengths by means of a first illuminator through a half mirror and an objective lens and cause light reflected on the medium to be incident on a spectrometer through the objective lens and the half mirror. A second illuminator illuminates a foreign material or scratch on the surface of the medium from an oblique direction with respect to the surface of the medium. Light is scattered from the foreign material or scratch and detected by first and second detectors. The first detector is placed in a direction defining a first elevation angle with the surface of the medium. The second detector is placed in a direction defining a second elevation angle with the surface of the medium.

Abstract: The present invention has an object of evaluating a recording and reproduction signal quality of a high density information recording medium by providing an index representing, in a detection signal including a plurality of pieces of edge shift information, how each edge is shifted.

Abstract: The subject innovation relates to systems and/or methodologies for using randomly positioned electromagnetic scatterers deposited into a predetermined region of an optical storage medium (e.g., Blue Ray DVD, HD DVD, CD, etc.) as a distinct three dimensional (3D) hard-to-copy digital rights management feature. A scatterers' topology is scanned using a matrix of antennas that sense the scatterers' electromagnetic response as the optical disc revolves at near-constant angular speed. The response, f, called an RF fingerprint, is then concatenated with an arbitrary text, t, that defines the digital rights management information imposed by the disk publisher.

Abstract: An apparatus is provided having a data transfer member, and a medium supported by a base adjacent the data transfer member. A medium tilting device supports the base and is selectively positionable to tilt the medium with respect to the data transfer member to simulate presenting the head to the medium at a desired angular orientation. A sensor measures a characteristic associated with a data transfer relationship between the data transfer member and the medium.

Abstract: A DPD tracking error signal detection apparatus includes the following. Four differentiators remove DC components and differentiate four signal with varying differential phases. The signals are then sampled and quantized by four A/D converters, and output to a non-inverting unit and an inverting unit. A phase inverter/compositor then leaves as-is or phase-inverts the output signals, according to a control signal. The non-inverting and the inverting unit each include two Hilbert transformers that phase-shift the output from the A/D converters, two delay units that delay the output of the other A/D converters to match the delay of the Hilbert transformers, two cross-correlators that calculate the cross-correlation between pairs of Hilbert transformers and delay units, and an adding unit that combines the cross-correlator results and outputs the combined result to the phase inverter/compositor.

Abstract: A test baseplate is configured to support and expose at least one storage device component to particle evacuation and particle analysis. The test baseplate includes a base having an upper surface that extends between an outer peripheral wall and an inner peripheral wall and having a lower surface defined by the inner peripheral wall. The test baseplate also includes a top clamp configured to be fastened to the upper surface of the base to secure the at least one storage device component to the base.

Abstract: A device for sensing a magnetic field is described. The device comprises first, second and third leads and a junction between the leads. The junction and leads are arranged in a plane and the junction is configured to exhibit quantum confinement in a direction perpendicular to the plane. The first lead is arranged on one side of the junction and the second and third leads are arranged on an opposite side of the junction. The first lead is configured to limit angle of spread of charge carriers entering the junction so that, when charge carriers flow into the junction from the first lead, the charge carriers form a substantially nondivergent beam.

Abstract: A signal processor includes an operational amplifier performing an operation on first and second signals, and amplifying a signal resulting from the operation based on an amplification control signal to remove an offset voltage, a buffer buffering an output signal of the operational amplifier and outputting a result of the buffering as differential signals, an automatic gain amplifier automatic gain amplifying the differential signals output from the buffer and outputting an automatic gain amplified signal as a single ended signal, a level shifter level shifting a level of the single ended signal including the offset voltage and outputting a level shifted signal as level shifted differential signals, and an offset voltage compensation unit converting a difference between the level shifted differential signals to a digital signal, detecting the offset voltage based on the digital signal, and outputting the amplification control signal to compensate for the detected offset voltage.

Abstract: A system includes a host device and a disk drive interfaced with the host device are described as well as an associated method. The disk drive includes a magnetic media for storing information using an actuator arrangement to perform a data access by moving at least one head proximate to the magnetic media. The information may be subject to corruption when the disk drive is exposed, during the data access, to a given stray magnetic field having a given minimum magnetic field intensity. The given stray magnetic field will not corrupt the information on the magnetic media with the actuator arrangement positioned away from the magnetic media. A stray magnetic field protection arrangement is configured for detecting an ambient magnetic environment for use in causing the actuator arrangement to park responsive to the detection of at least the given minimum magnetic field intensity.

Abstract: In a method for implementing track shape control during a self servo-write process, an error in a targeted path for writing servo data onto a first track of a disk is detected. The error is correlated with a second error for a targeted path in a previously written track of the disk. A correction is generated for a feed-forward signal used to position a writing element which is used to write servo data for a subsequent track of the disk.

Abstract: The present invention is designed to support plural servo patterns by setting a portion of the information of the servo pattern as a detection pattern, comparing the demodulated pattern of the portion of the information with the detection pattern, and controlling an operation timing of a test according to a result of the comparison.

Abstract: The invention relates to a method of determining the quality of data on an optical disc. The method comprises performing a quality scan resulting in quality information about at least part of the data on the optical disc; organizing the quality information in groups, each group comprising quality information corresponding to a predetermined zone on the optical disc; and computing a zone quality information parameter for each group based on the quality information corresponding to that group.

Abstract: According to one embodiment, an information processing apparatus includes an optical disk drive, a power supply module configured to supply power to the information processing apparatus, an acquisition module configured to start acquisition of status information of the optical disk drive when the power supply module supplies power to the information processing apparatus, a storage module configured to store feedback information corresponding to each condition predetermined for the status information of the optical disk drive, and a notification module configured to notify the apparatus of feedback information which is read from the storage module in correspondence with the condition when the status information of the optical disk drive acquired by the acquisition module matches the condition.

Abstract: A magnetic head inspection device inspects the write track width of a thin film magnetic head in a phase as early as possible during the manufacturing process. A recording signal (excitation signal) is input from bonding pads to the thin film magnetic head in a rowbar, and the magnetic field generated by the write pole (element) included in the thin film magnetic head is observed directly by using a magnetic force microscope (MFM), a scanning Hall probe microscope (SHPM), or a scanning magneto resistance effect microscope (SMRM) that performs a scanning motion at a position equivalent to the flying height of the magnetic head. In this manner, a shape of the generated magnetic field instead of the physical shape of the write pole (element) is measured; thus, a non-destructive inspection can be performed on the effective magnetic track width.

Abstract: An eccentricity measurement method of measuring the eccentricity between a center of a connection portion of a rotary disk of a rotary encoder connected to a rotary shaft of a rotary member, and a center of a scale provided at the periphery of the rotary disk. The method includes forming, on the rotary disk, a circle pattern concentric with the scale and at least three straight-line patterns intersecting or contacting the circle pattern and the connection portion; and measuring an amount and direction of the eccentricity of the rotary disk by comparing a coordinate of the center of the connection portion, calculated from coordinates of intersections of the straight-line patterns and the connection portion, with a coordinate of the center of the scale, calculated from the coordinates of intersections of the straight-line patterns and the circle pattern.

Abstract: Method and apparatus for compensating for differences in translation path geometries of transducers used to access a data storage medium. A compensation profile is generated in relation to radial error between a first translation path geometry of a first transducer and a different, second translation path geometry of a second transducer. A control circuit directs the first transducer to write data to a rotatable data storage medium in relation to the compensation profile to emulate the second translation path geometry. In some embodiments, the control circuit comprises a data signal clock generator, a motor rotation clock generator, and a transducer radial translation clock generator. A nearest pulse detector identifies a closest clock signal pulse to a once-per-revolution (OPR) rotational reference, and the control circuit adjusts a frequency of the associated clock signal coincident with said closest pulse.

Abstract: A hard disk inspection apparatus comprises an image pickup device which includes an inspection region portion of a disk surface including an edge of a hard disk, and which picks up an image of reflected light from the inspection region portion, an edge detection processing device which detects an edge position of the hard disk, an information acquisition device which acquires specification information that defines several values of a inspection target hard disk, a window separation device which separates the captured image into windows, an image analysis device which performs data processing for each of the regions into which the captured image is separated by the window separation device, and acquires information regarding positions and sizes of dust for each region, and a display control device which displays a result obtained by the image analysis device on a monitor screen.

Abstract: An apparatus correctly measures motion characteristics a head gimbal assembly exhibits when turned in a radial direction of a hard disk. The apparatus includes an assembly support to fixedly support the head gimbal assembly on a center axis that corresponds to a rotation axis around which the head gimbal assembly is turned in actual use, a disk drive to rotatably support the hard disk and turn around a turn axis that is concentric with the center axis on which the head gimbal assembly is fixedly supported, and a turn unit to turn the disk drive around the turn axis, thereby creating a relative turn of the head gimbal assembly with respect to the hard disk.

Abstract: According to one embodiment, a storage device that reads data from and writes data to a recording medium, which is rotationally driven by a motor, by a head, includes a ground disconnector, a motor voltage application module, and a Coulomb force detector. The ground disconnector disconnects a connection between the motor and ground. The motor voltage application module applies voltage to be supplied to the motor. The Coulomb force detector detects read output while the motor voltage application module applies voltage to the motor. The Coulomb force detector then calculates, based on the read output, an amount of change in floating height of the head to read data from or write data to the recording medium to detect the magnitude of Coulomb force generated by electrical charging of the recording medium based on the applied voltage and the amount of change in floating height of the head.

Abstract: Frequency response is characterized for mechanical components of a multirate system operating in a closed-loop environment. A disturbance is injected at the frequency of interest and at each of the alias frequencies thereof as an input into the multirate system, and a matrix equation composed of resulting measurements of the response of the multirate system is solved to compute the frequency response at the frequency of interest and at each of the alias frequencies. The resulting frequency response can be used to synthesize the transfer function of the entire system, which allows simulation and evaluation of the relative performance of multiple controller designs without the need for further frequency response measurements.

Abstract: A method for measuring a variation in the floating amount of a magnetic head comprising: measuring the ambient temperature which is a temperature of the magnetic storage apparatus; reading a signal recorded in the magnetic recording medium; measuring a signal value which is a value related to a signal read in the reading; and calculating a variation in the floating amount of the magnetic head based on relationship information which is information representing a relationship between the ambient temperature and signal value that have previously been measured, measurement value which is the ambient temperature measured in the measuring of the temperature, and signal value measured in the measuring of the signal.

Abstract: A recording and replaying device is provided in which a user can easily diagnose failure when a built-in storage device of the device fails. In a normal operation state, a microcomputer controls a signal path switching mechanism to connect a signal processing device and a hard disk drive (HDD). In an abnormal operation state, the microcomputer sets a USB interface device to effective state, and controls the signal path switching mechanism to connect the USB interface device and the hard disk drive (HDD), so that the hard disk drive is recognized by an external personal computer as a USB mass storage.

Abstract: A magnetic storage apparatus has a reproducing head to reproduce information from a perpendicular magnetic recording medium that is recorded with servo information, eccentricity correction data and read/write data. The apparatus further has a filter part to filter a reproduced output of the reproducing head by filtering the servo information which has a differentiated waveform by a non-differentiating characteristic and by filtering the eccentricity correction data and the read/write data which have rectangular waveforms by a differentiating characteristic, a demodulating part to demodulate the servo information, the eccentricity correction data and the read/write data that are filtered by the filter part, and a servo system to carry out a control process including an eccentricity control based on the servo information and the eccentricity correction data that are demodulated.

Abstract: In order to provide a magnetic recording medium having excellent electromagnetic conversion characteristics, a magnetic recording medium (10) is provided with a substrate (12), and a magnetic recording layer (20) formed on the substrate (12). The magnetic recording layer (20) is provided with a granular layer (32), i.e., a magnetic layer, including magnetic grains and a nonmagnetic material surrounding the magnetic grains in a section parallel to the main surface of the substrate. The ratio of the long diameter to the short diameter of each magnetic grain contained in the granular layer (32) is calculated in the section. In the histogram of such ratio, a half width at half maximum of the histogram is 0.6 or less and the variance of grain diameters of the magnetic grains in the section is 20% or less of the average grain diameter of the magnetic grains.

Abstract: An equalizer (22) performs a PR equalization of a reproduced signal waveform output from an A/D converter (21). A reference-waveform generation unit (42) generates a reference reproduced-waveform based on a recording data train estimated from the reproduced signal waveform by a recognition unit (30). An equalization-error calculation unit (43) calculates an equalization error between the reference reproduced-waveform and the reproduced signal waveform. A transient equalization-error detector (44) extracts equalization error information, as a transient equalization error, at the time instant at which the reference reproduced-waveform assumes a specific level, and at which the specific level-value and a level-value of the reference reproduced-waveform at one channel clock before or after the time instant satisfy therebetween a specific relative relationship. The extracted transient equalization error is used as an index showing the quality of the recorded mark.

Abstract: A recording method for irradiating a multi-layered optical recording medium with a laser beam to record information thereon. The optical recording medium can form a first information recording layer that is the farthest from a light incident surface, a second information recording layer that is the second farthest from the light incident surface, and at least one third information recording layer that is located closer to the light incident surface than the second information recording layer is. The method is to record information on the second information recording layer when all the information recording layers other than the second information recording layer are either blank or have been completely recorded. This allows for realizing high-quality information recording in consideration of adherence of foreign matters or occurrence of scratches.

Abstract: The present invention provides a technique for converting burst data to digital data, applying FFT operation to 2n (n is an integer) pieces of digital data in response to any start signal synchronized with a sector signal, applying a window function centered around data corresponding to a frequency of a burst data signal component before the FFT operation, and performing head positioning based on a result as the detected value of the burst data.

Abstract: According to an aspect of the embodiment, a MCU divides a target track into recording areas on magnetic disks, assigns the recording areas to the magnetic heads, and performs write control during one rotation of the magnetic disks so that the magnetic heads write data in the recording areas assigned to the respective magnetic heads. After data writes by the magnetic heads, the MCU verifies whether data in the testing areas of the tracks adjacent to the target track is held without being erased.

Abstract: An offset amount between heads is calculated by positioning a head in a designated track under an ON track servo control, obliquely writing test data by moving the head in a radial direction of the magnetic recording medium at a designated moving speed K to cross the designated track and at least one track adjacent to the designated track according to a write start signal, reading the oblique test data by the read head from the adjacent track under the ON track servo control, detecting a peak position of a read voltage by using a read voltage characteristics of the read signal in the adjacent track and calculating the offset amount between the heads by detecting a scan time up to the peak position of the read voltage.

Abstract: A test data is written in tracks of a DTM by making the tracks eccentric by accessing a plurality of tracks by forcibly making a composite magnetic head eccentric under an ON track servo control. The test data written in the tracks which are pseudo-eccentric are written in the tracks with the original write sensitive width of a write head. It is possible to obtain a read characteristics profile having a peak by tracing and reading the test data while moving the composite magnetic head (read head) which is forcibly made eccentric in a radial direction.

Abstract: A recording strategy for specifying an output waveform of a laser beam to be applied to a recording layer of an information recording medium is adjusted by the following recording strategy adjusting method. The recording strategy adjusting method includes a base strategy determining step of determining a basic recording strategy; a first top pulse width setting step wherein the shortest mark in a pattern row formed on the recording layer of the information recording medium is specified after the base strategy determining step, and the width of a top pulse, i.e., a pulse for recording the shortest mark, is set; and a step of adjusting a power, including a recording power and a bias power, for recording.

Abstract: An information recording apparatus (1) is provided with: a recording device (11) for recording a data pattern onto a recording medium (100); a reading device (11) for reading the data pattern, thereby obtaining a read signal; an amplitude limit filtering device (15) for limiting an amplitude level of the read signal by using a predetermined amplitude limit value, thereby obtaining an amplitude limit signal and for performing a high frequency emphasis filtering process on the amplitude limit signal, thereby obtaining an equalization-corrected signal; a measuring device (19) for measuring jitter of the equalization-corrected signal or the read signal; a detecting device (20) for detecting the data pattern of the equalization-corrected signal; and an adjusting device (21) for adjusting a recording condition such that the jitter satisfies a desired condition, with reference to the data pattern.

Abstract: A magnetic recording medium having a first lubricant layer formed on the surface thereof and a gas sensor are disposed in a housing. The gas sensor detects gas by adsorbing the gas on a detection surface thereof The detection surface is formed with a second lubricant layer made of the same lubricant agent as that of the first lubricant layer.

Abstract: According to one embodiment, an adjusting element adjusts a dynamic flying height of a head lying over a disk in accordance with the power supplied to it. A calculation module calculates the power to supply to the adjusting element, from a barometric pressure detected by a barometric pressure sensor. A failure detection module detects failure of the barometric pressure sensor. An unload controller predicts an abnormal dynamic flying height of the head from the failure detected and then instructs the unloading of the head away from the disk.

Abstract: A metrology system for measuring the magnetic properties of a magnetic recording medium layer on a device used for perpendicular recording.

Abstract: This invention provides an information processing method and apparatus, which can set all extent sizes of data divisionally recorded on a disk to be equal to or larger than the minimum recording unit, and can guarantee continuous reproduction of the divisionally recorded data. Of data divisionally recorded on a recording medium (5), data which corresponds to an end portion of that data and cannot be recorded as a recording area equal to or larger than a minimum recording unit specified in the recording medium (5) due to the presence of a recording area (6) of another data, that has already been recorded on the recording medium (5), is re-recorded on a recording area equal to or larger than the minimum recording unit. At this time, new data is generated by combining data less than the minimum recording unit, and data recorded in another recording area, and the new data is re-recorded on a new recording area.

Abstract: A method of measuring a magnetic write width of a magnetic head MWWHEAD and a magnetic write width of a discrete track medium MWWMEDIUM, which is insensitive to possible distortion in the track profile in discrete track recording (DTR) is provided.

Abstract: An upward warp of a terminal pad of a flexible cable which is kept horizontal by a suction head is prevented by a pressing arm which contacts with an upper surface of a rear portion of the flexible cable.

Abstract: In one implementation, an assembly for testing a head gimbal assembly comprises a rotatable test disc, a mounting surface configured to mount the head gimbal assembly, and a shroud covering the head gimbal assembly. The mounting surface is located in proximity to the test disc to facilitate loading the head gimbal assembly on the test disc. The shroud is configured to shield the head gimbal assembly from airflow produced when the test disc rotates.

Abstract: An optical disk processing system having a recording unit and a printing unit is provided. An optical disk processing system comprises a printing unit and a recording unit. An optical disk is driven with a low torque and then with a high torque. Based on reaching times until target rotational speeds are reached when the optical disk is driven with the low torque and the high torque, a type of the optical disk is judged. Loading of a plurality of optical disks is detected when the judgment results for low torque and for high torque do not match.

Abstract: Provided is a method for testing a magnetic recording medium which is capable of carrying out a certification test with a high degree of accuracy.

Abstract: The optical scanning device [10] is arranged for scanning a record carrier [1]. The record carrier has an outer face [7]. The scanning device comprises a radiation source [11] for generating a radiation beam [12] and an objective system [25] having an exit face [26] arranged for evanescent coupling of the radiation beam between the exit face and the outer face and for converging the radiation beam to a focus [27]. A tilt measuring system [67, 77] provides a tilt signal [87; 88] representing a tilt angle between the objective system and the record carrier. A control unit [95] determines a distance signal representing a distance between the exit face and the focus from the tilt signal.

Abstract: A magnetic recording/reproducing apparatus 100 includes: a magnetic head 1; a magnetic recording medium 2; a spindle 3 and a spindle motor 4; a suspension arm 5; a voice coil motor 6; and a control unit 7. The control unit 7 has: a motor driver 8; a head amplifier 9; a read/write channel 10; a laser driver 11; and a controller 12. The controller 12 has: a preliminary recording unit 13; a judgment unit 14; an extraction unit 15; a drive condition determining unit 16; and a preliminary recording terminating unit 17. Based on a reproduction signal evaluation value obtained using these units and a predetermined reference value, a drive condition is determined which is suitable for recording onto the magnetic recording medium 2.

Abstract: A method and system are provided, for reducing the amount of radial to vertical crosstalk in an error signal in an optical record carrier reader. The method comprises the steps of: measuring error signals in a plurality of error signal control loops of the reader, comprising a focus error signal control loop; calculating power dissipation in each error signal control loop for determining the amount of radial to vertical crosstalk in the focus error signal control loop. Countermeasures may be applied to the error signal control loops to minimize or optimize the radial to vertical crosstalk.

Abstract: A method of determining the transition shift timing in a measured optical signal from an optical recording medium as well as applications of the method in connection with optimizing a write strategy and analyzing the write quality for an optical recording medium are disclosed. The method comprising the step of: providing values of a measured optical signal, providing modulation bits corresponding to the measured optical signal, calculating a model signal by means of an optical channel model, and determining an output timing of the leading and trailing edges from a mathematical model. The method being a recursive method which is continued until a predetermined criterion is fulfilled. The final output is the average transition shifts of the channel bits of the measured CA signal as they are on the optical recording medium.