Abstract: An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted

Abstract: Various embodiments of the present invention are generally directed to adaptively determining an updated repeated runout (RRO) correction value to correct for RRO error in the placement of a servo seam, by iteratively combining a weighted initially estimated RRO correction value for the seam with a position error signal (PES).

Abstract: Various embodiments of the present invention are generally directed to using a transducer to transfer data during a transducer displacement operation at a time during such operation when the transducer is substantially stationary.

Abstract: Apparatus is provided for fast-adjustment of the position of a plant in a servo system in which a servo output indicative of the plant position is provided to a positioning system for positioning the plant in dependence on the servo output. The apparatus includes an adjustment signal generator, operable in a fast-correction mode and a shock-compensation mode, for generating an adjustment signal for supply to the positioning system to effect fast positional adjustment of the plant. The apparatus also has an adjustment controller for receiving the servo output. The adjustment controller is adapted to detect from the servo output occurrence of a disturbance affecting positioning of the plant and, in response, to initiate the shock-compensation mode of the adjustment signal generator. The adjustment controller is further adapted to initiate the fast-correction mode of the adjustment signal generator in response to indication of an error in positioning of the plant.

Abstract: A disk drive is disclosed comprising a disk and a head actuated over the disk by a voice coil motor (VCM) comprising a voice coil, wherein the VCM is controlled by a VCM control loop comprising an IR voltage detector. The IR voltage detector is updated by measuring a first back EMF voltage of the voice coil, and after measuring the first back EMF voltage, applying a first control current to the voice coil for a first interval and applying a second control current to the voice coil for a second interval. After the second interval, a second back EMF voltage is measured, and a delta voltage is computed relative to a difference between the first back EMF voltage and the second back EMF voltage. The IR voltage detector is adjusted in response to the delta voltage and at least one of the first and second control currents.

Abstract: An actuator capable of providing movement forces in a first direction, a second direction, and a third direction is provided. The actuator includes two sets of repelling permanent magnets and yokes, a focusing coil, a tracking coil, and a tilting coil. The repelling and attractive fields generated by the permanent magnets enable the coils to generate independent movements in three axial directions. The two sets of permanent magnets are placed in a repelling position, with a small space between the two magnets to generate a field whose magnetic forces repel and attract within the surrounding range. The focusing, tilting and tracking coils are engaged with the lens holder whose movements in the first, second and third directions are determined by the amplitude and direction of the electric current in the focusing, tilting and tracking coils respectively.

Abstract: A data storage drive comprises a storage disk, a read/write head, and signal processing circuitry in signal communication with the read/write head. The read/write head is operative to read data from and write data to the storage disk at a plurality of data transfer rates. Moreover, the signal processing circuitry is powered by a variable power source. The variable power source varies supply voltage to the signal processing circuitry as a function of a current one of the data transfer rates of the read/write head. Power consumption is reduced in this manner.

Abstract: According to one embodiment, a disk drive having a disk, a read head, a servo controller, and a CPU. In the disk, a multi-spiral servo pattern is recorded. The read head reproduces a hexagon-shaped detection signal from the multi-spiral servo pattern. The servo controller generates amplitudes values for respective frames, from the multi-spiral servo pattern. The CPU performs positional-error calculation by using the amplitude values for the frames. Upon detecting a positional change of the head is detected, the CPU performs the positional-error calculation by using the amplitude values generated at the time of replacing the frames with other frames, and corrects the positional error by adding an offset determined from the positional change of the head, to the result of the positional-error calculation.

Abstract: An optical disc apparatus implementing a PRML and capable of recording and reading a plurality of disc media with different recording densities, wherein read compatibility between drives is ensured without relying solely on the error correction capability of the ECC (error correction code). A phase comparator provided in a PLL compares each value of an input signal sequence with a designated threshold value in order to determine an edge. The optical disc apparatus can record and read a plurality of disc media with different recording densities while ensuring read compatibility.

Abstract: According to one embodiment, a servo-writing method for use in a disk drive, in which a CPU causes a head to record final patterns in a disk, by using the multi spiral servo pattern recorded in the disk. The CPU uses a designated spiral servo pattern, positioning the head at a target position, so that the head may write the final patterns at the target position and may read sector-address data contained in the final patterns.

Abstract: An optical recording medium driving device includes an optical head, an evaluation signal generating section, a focus servo section, a spherical aberration correction section, a focus bias adjuster, and a system controller. The optical head has a focus servo mechanism and a spherical aberration correction mechanism, irradiates a laser light, and detects a reflected light. The evaluation signal generating section generates, based on the reflected light, an evaluation signal. The focus servo section drives the focus servo mechanism according to a focus error signal to perform focus servo. The spherical aberration correction section drives the spherical aberration correction mechanism to perform spherical aberration correction. The focus bias adjuster adds focus bias to a focus loop. The system controller performs an operation for setting an adjustment spherical aberration correction value.

Abstract: A system and method for reducing tape wear in a magnetic tape system. A tape drive comprises a wrap reverse location controller. The wrap reverse location controller determines a magnetic tape reversal location. The tape drive reverses the direction of the magnetic tape at the reversal location. The wrap reverse location controller determines the tape reversal location by varying, relative to the tape heads, the longitudinal tape location at which tape direction reversals are performed at each end of the tape.

Abstract: In a method of head-disk contact detection in a hard disk drive, a Radio Frequency (RF) carrier signal is injected into a slider which is flying above a surface of a disk in a hard disk drive. A modulated version of the RF carrier signal is received from the slider. The modulated version of the RF carrier signal is demodulated to achieve a demodulated signal. A signal spectrum of a range of frequencies in the demodulated signal is monitored for activity indicative of a contact between a head of the slider and the surface of the disk. An occurrence of the contact is determined based upon an occurrence of the activity.

Abstract: An apparatus, system, and method are disclosed for aberration compensation. In one embodiment, a first compensation lens used in conjunction with a second compensation lens to produce a conical beam used to read from, or write to, an optical medium. An Nth order compensation equation is used to optimize aberration errors associated with accessing the optical medium. The present invention may include a displaceable focus lens positioned relative to an optical medium. The focus lens may be displaced when the conical beam's focal length is adjusted. A displacement equation is presented to determine the preferred placement of the focus lens. By compensating for aberration, read/write errors may be reduced while accessing optical media thus increasing system robustness and facilitating the use of additional layers on optical media.

Abstract: A servo signal recording apparatus of the present invention is provided with a tape motion measurement unit 5 that measures the lateral motion of a magnetic tape 3, and outputs tape motion information, a signal processing unit 20 that generates a servo signal that includes the tape motion information output from the tape motion measurement unit 5, and a servo signal recording head 4 that records the servo signal generated by the signal processing unit 20 to the magnetic tape 3. The tape motion measurement unit 5 measures the tape motion prior to the timing at which a servo signal is recorded to the magnetic tape 3 by the servo signal recording head 4, and records a servo signal that includes the tape motion information. This configuration enables a servo signal that can be used to perform tracking servo at high speed and with high accuracy to be written to a magnetic tape.

Abstract: A system is capable of detecting a “large” shock. In contrast to just any shock, a large shock exceeds some threshold of magnitude or duration and may generate particles and/or the deposit of particles on a recording head, which can result in write errors. Responsive to detection of a large shock, the system can take corrective action, such as executing one or more corrective action seeks after detection of the large shock or executing a series of corrective actions seeks during a certain number of load operations after detection of the large shock. RAW verifications may be performed to confirm correct write operation of the recording head after such corrective action.

Abstract: An optical disc device includes an optical pickup for irradiating optical discs with laser and detecting light reflected by the disc to generate received light signals, optical pickup driving means for driving the pickup radially, traverse signal generation means for generating traverse signals forming a pulse at the pickup's crossing a track by binarizing the received light signal based on binary threshold, movement control means for recognizing moving amount and speed of the pickup based on the traverse signal and controlling the optical pickup driving means based on the recognition result for the pickup's seeking to the target, and abnormality monitoring means for sending abnormality notices to the movement control means when pulse interval of the traverse signal exceeds the threshold, the movement control means, after temporarily stopping seek according to the abnormality notice, recognizes the temporary stop position for the optical pickup's seeking from the position to the target.

Abstract: There is provided an optical disc recording apparatus containing a small-area circuit that is adaptable to both of the formats of DVD-R/RW and +RW/+R standards. The apparatus is provided with a circuit (106) for converting a 32T-cycle binarized wobble signal based on the +RW/+R standard into a 186T-cycle binarized wobble signal based on the DVD-R/RW standard, and the converted 186T-cycle binarized wobble signal is selected with a selector (108) during +RW/+R recording while the 186T-cycle binarized wobble signal is selected during DVD-R/RW recording, whereby subsequent PLL circuits are shared to reduce the circuit scale.

Abstract: Embodiments of the present invention provide a magnetic disk drive capable of suppressing variations in flying height of a magnetic head caused by decrease in the amount of a low density gas inside a housing and a control method therefore. According to one embodiment, the magnetic disk drive includes a magnetic head, a magnetic disk, and a housing containing the magnetic head and the magnetic disk, wherein the housing is filled with a low density gas having a lower density than air. An amount of the low density gas in the housing is estimated and, based on the amount of the low density gas, a flying height of the magnetic head from a surface of the magnetic disk is controlled.

Abstract: Embodiments of the present invention help to adjust the recess depth of a head element portion of a head slider. In an embodiment of the present invention, in a test step in manufacturing an HDD, the HDD examines the recess depth of a head element portion and decreases and adjusts the recess depth if the recess depth of the head element portion does not satisfy the predetermined condition. The HDD moves an actuator to a ramp of a retract position and supplies power to a heater in a head slider. If the heater power is large, the head element portion undergoes plastic deformation. The plastic deformation of the head element portion decreases the recess depth of the head element portion.