Abstract: Embodiments of the invention provide control of a disk data storage device to prevent off-track writing. In one embodiment, the SA acquires the CYLIDs and ADC Values generated from the SERVO SIGNALs acquired previously, and generates DACOUT which defines a driving current of the VCM driver. The SA monitors the DACOUT generated and determines whether the DACOUT is within a predefined range. If the DACOUT is outside the predefined range, data writing is inhibited. By monitoring the DACOUT, it is possible for the VCM driver to detect supply of an overcurrent to the VCM driver 210 beforehand, and off-track writing can thus be prevented.

Abstract: Embodiments of the present invention provide a disk drive capable of reducing, by means of simple control, vibrations applied to the drive and vibrations occurring in the drive, and a control method for controlling the disk drive. In one embodiment, a servo system comprises a sensor unit for detecting vibrations, a correction signal generator for, when the sensor unit detects vibrations, generating a correction signal, a position error signal generator for generating a PES signal on the basis of servo data read out from a disk and a target position, a servo controller for generating a servo control signal for controlling a position of a head on the basis of the PES signal, and a servo controller for generating a driving signal on the basis of the correction signal and the servo control signal.

Abstract: In a semiconductor laser 1, a current blocking layer 19 covers a p-type 2nd cladding layer 17 and a p-type cap layer 18 that extend in a lengthwise direction of an optical resonator, at both a light-emission end and an end opposite the light-emission end, to thus form non-current injection regions in an optical waveguide. By making current blocking layer 19 at the light-emission end large enough that carriers flowing from a current injection region do not reach the light-emission end surface, the light intensity distribution in the near field at the light-emission end surface is strongly concentrated, allowing the horizontal divergence angle of an emerging laser beam to be enlarged. This structure makes it possible to enlarge the horizontal divergence angle independently after having optimized the thickness of cladding layers and the size of the current injection region.

Abstract: A method for manufacturing a semiconductor laser. As a preparative step for coating an end face of a resonator with a dielectric film, a cleavage plane of a semiconductor laminated structure that is to be the end face is subjected to a plasma cleaning to prevent a conductive film, which absorbs laser light, from attaching to the cleavage plane. During the plasma cleaning, a first process gas containing argon gas and nitrogen gas is introduced into a vacuumed ECR sputtering apparatus. After the cleavage plane is exposed to the first process gas in the plasma state for a certain time period without application of a voltage, a second process gas containing argon gas and oxygen gas is introduced, and the cleavage plane is exposed to the second process gas in the plasma state while a voltage is applied to the silicon target.

Abstract: A semiconductor laser includes an active layer formed on a substrate and a pair of cladding layers sandwiching the active layer. On at least one of resonator end faces of the semiconductor laser, a first dielectric film with hydrogen added therein is provided. Between the first dielectric film and the resonator end face, a second dielectric film for suppressing the diffusion of hydrogen is provided. Even when a semiconductor laser with an end face coating film including a hydrogen-added film is exposed to high temperatures, peeling of the end face coating film and deterioration of the end face coating film can be suppressed.

Abstract: To provide a semiconductor laser device for which a horizontal divergence angle of a laser beam can be improved independently of optimization of other properties such as a cladding layer thickness and a current injected region size. A current blocking layer covers a larger area of a p-type second cladding layer and p-type cap layer extending in a resonator length direction, on a light emitting end face side than on an opposite end face side. Thus, current uninjected regions are formed in an optical waveguide. The current blocking layer (current uninjected region) on the light emitting end face side is set long enough to prevent carriers, which flow in from a current injected region, from reaching alight emitting end face. In this way, a light intensity distribution of a near-field pattern on the light emitting end face is concentrated, thereby increasing a horizontal divergence angle of a laser beam.

Abstract: Embodiments of the invention perform a stable data write operation at a low operating ambient temperature and promptly perform a write command process within a magnetic recording apparatus that employs a load/unload design. In one embodiment, write heads unloaded on a ramp are completely preheated before magnetic disks reach their rated rotation speed. This preheat operation takes time T1. After completion of write head preheating, the write heads are loaded from the ramp. This loading operation takes time T2. Since time T1 and time T2 do not sequentially elapse, it is possible to prevent a write operation from being rendered unstable by thermal protrusion while expediting a write command process.

Abstract: Embodiments of the invention reduce the noise occurring when the lubricating layer on the magnetic disk is smoothed. In one embodiment, a magnetic disk drive has a read/write mode parameter table for generating an electric current to be supplied to a voice coil motor when the magnetic head performs data read/write operations on the magnetic disk. The magnetic disk drive also has a smoothing mode parameter table for generating another electric current to be supplied to the voice coil motor when neither a data read nor a write operation is performed on the magnetic disk. The CPU refers to either the read/write mode parameter table or the smoothing mode parameter table and controls the electric current to be supplied to the voice coil motor.

Abstract: A semiconductor laser includes an active layer formed on a substrate and a pair of cladding layers sandwiching the active layer. On at least one of resonator end faces of the semiconductor laser, a first dielectric film with hydrogen added therein is provided. Between the first dielectric film and the resonator end face, a second dielectric film for suppressing the diffusion of hydrogen is provided. Even when a semiconductor laser with an end face coating film including a hydrogen-added film is exposed to high temperatures, peeling of the end face coating film and deterioration of the end face coating film can be suppressed.

Abstract: A semiconductor laser includes an active layer formed on a substrate and a pair of cladding layers sandwiching the active layer. On at least one of resonator end faces of the semiconductor laser, a first dielectric film with hydrogen added therein is provided. Between the first dielectric film and the resonator end face, a second dielectric film for suppressing the diffusion of hydrogen is provided. Even when a semiconductor laser with an end face coating film including a hydrogen-added film is exposed to high temperatures, peeling of the end face coating film and deterioration of the end face coating film can be suppressed.

Abstract: To improve the probability of error correction, thereby generating correct read data. Data is read from the same sector by a number of times and a majority decision is done in the same address, thereby the most frequently read value is regarded as the true data value in the address. For example, for an address 00, “00” is handled as a true data value.

Abstract: A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method (and structure) includes detecting the reference bits across a pattern on the rotating disk, and analyzing a time interval between adjacent ones of the reference bits.

Abstract: In a semiconductor laser 1, a current blocking layer 19 covers a p-type 2nd cladding layer 17 and a p-type cap layer 18 that extend in a lengthwise direction of an optical resonator, at both a light-emission end and an end opposite the light-emission end, to thus form non-current injection regions in an optical waveguide. By making current blocking layer 19 at the light-emission end large enough that carriers flowing from a current injection region do not reach the light-emission end surface, the light intensity distribution in the near field at the light-emission end surface is strongly concentrated, allowing the horizontal divergence angle of an emerging laser beam to be enlarged. This structure makes it possible to enlarge the horizontal divergence angle independently after having optimized the thickness of cladding layers and the size of the current injection region.

Abstract: A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method (and structure) includes detecting the reference bits across a pattern on the rotating disk, and analyzing a time interval between adjacent ones of the reference bits.

Abstract: Embodiments of the invention provide control of a disk data storage device to prevent off-track writing. In one embodiment, the SA acquires the CYLIDs and ADC Values generated from the SERVO SIGNALs acquired previously, and generates DACOUT which defines a driving current of the VCM driver. The SA monitors the DACOUT generated and determines whether the DACOUT is within a predefined range. If the DACOUT is outside the predefined range, data writing is inhibited. By monitoring the DACOUT, it is possible for the VCM driver to detect supply of an overcurrent to the VCM driver 210 beforehand, and off-track writing can thus be prevented.

Abstract: Embodiments of the invention are directed to detecting an abnormality in head flying height. In one embodiment, an AGC controller establishes the gain of the reproduced signal through gain adjustment using the servo AGC of the servo signal. A digital filter performs filtering processing by use of the obtained gain data g and the gain data of previous sectors. A comparative judgment section obtains filtered gain data G from the digital filter and compares the gain data G with a reference value CRITERIA to determine whether the flying height is normal or abnormal. If the gain G is larger than the reference value CRITERIA, then the data write operation is inhibited. The filter parameters of the digital filter are programmable parameters which can be set and changed.

Abstract: The hard disk drive comprises: a magnetic disk 2 having servo information stored; magnetic heads 4 seeking on the magnetic disk 2 and staying at a predetermined position to read or write data; a voice coil motor 6 moving the magnetic heads 4 to the predetermined position of the magnetic disk 2; a position controller supplying a driving current to the voice coil motor 6 based on the servo information read by the magnetic heads 4. The position controller includes: a CPU 12 outputting a speed control value based on the servo information; a DAC 7 and a VCM driver 8 converting the speed control value into the driving current; and a controller 10 limiting a driving speed of the voice coil motor 6 in a case that an output timing of the speed control value is shifted.

Abstract: A method for manufacturing a semiconductor laser. As a preparative step for coating an end face of a resonator with a dielectric film, a cleavage plane of a semiconductor laminated structure that is to be the end face is subjected to a plasma cleaning to prevent a conductive film, which absorbs laser light, from attaching to the cleavage plane. During the plasma cleaning, a first process gas containing argon gas and nitrogen gas is introduced into a vacuumed ECR sputtering apparatus. After the cleavage plane is exposed to the first process gas in the plasma state for a certain time period without application of a voltage, a second process gas containing argon gas and oxygen gas is introduced, and the cleavage plane is exposed to the second process gas in the plasma state while a voltage is applied to the silicon target.

Abstract: A method for producing a semiconductor device of the present invention includes forming a surface electrode on a semiconductor element, forming a solder layer by plating on one principal surface of the surface electrode, mounting the semiconductor element on the sub-mount so that the solder layer contacts a principal surface of the sub-mount, and bonding the sub-mount and the semiconductor element to each other via the solder layer.

Abstract: To provide a method of starting a data storage unit which allows a computer system to be used as early as possible. The present invention relates to a method for starting up a computer system having a data storage unit equipped with an actuator arm which supports a flexible cable. The method allows a command from the host computer to be processed before generation of corrected tension data for the flexible cable. The method includes the steps of turning on power; executing a start operation, excluding generation of corrected tension data of the flexible cable; causing an access command from a host computer to be in an executable state, following the step of executing a start operation; and executing generation of corrected tension data of the flexible cable, following the step of causing an access command from a host computer to be in an executable state.