Abstract: A method of and apparatus for generating a reader-to-writer offset for a head positioned over a track on a disc in a disc drive having a plurality of tracks is disclosed. A reader and a writer are mounted on the head in a non-overlapping manner with a gap between the reader and the writer, which is known as the reader-to-writer offset. A disc drive controller is operably connected to the reader and the writer. The disc drive controller determines the reader-to-writer offset of the head for each track by computing the difference between a first head position x1 and a second head position x2. The first head position x1 is an optimal head position for writing information on the track and the second head position x2 is a midpoint of an off-track capability (OTC) of the head.

Abstract: A method for reducing the accumulation of actuator bearing grease in hard disk drives includes periodically forcing the disk drive into multiple unload/load cycles after extended read/write sessions wherein the disk drive has not unloaded. While the disk drive is unloading, the current required to unload the read/write head is monitored. Based on the value of the current, the frequency of the unload/load cycle is adjusted.

Abstract: Methods and systems in a data storage device selectively employ a seek time array and/or a seek time list to accurately predict a time required for a seek operation to move a transducer in the data storage device a given seek distance. The seek time list and/or seek time profiles are automatically compiled in the data storage device based on seek time entries located in a servo data table located in the data storage device.

Abstract: A magnetic disk device having a head integrated circuit mounted on a magnetic head supporting mechanism. In order to secure the reliability by controlling the integrated circuit temperature below a predetermined level, the difference in the integrated circuit cooling ability which varies with the radial position on the disk is quantified, so that power (signal) sufficient to maintain a constant temperature according to the integrated circuit temperature is supplied to the integrated circuit. Since the cooling ability at a given radial position of the integrated circuit is not exceeded by the power consumption, the integrated circuit temperature can be maintained below a predetermined level.

Abstract: This invention comprises an architecture for voltage mode control of a voice coil motor in a hard disk drive. In contrast to conventional current mode control, coil current is not sensed or measured, which simplifies the feedback design with less hardware required in the implementation. Common design methodologies for the square root velocity profile, linear velocity profile and regulator/estimator control system designs can be migrated from the current mode architecture to the voltage mode architecture.

Abstract: A method and an apparatus select the spindle rotation speed for writing servo tracks to a disk based on measured performance of the head-disk assembly. The position error values are measured and analyzed to generate a position error metric. Based on the value of the position error metric, a spindle rotation speed is selected for use when writing servo tracks to a disk.

Abstract: A method and apparatus for compensating for repeatable run-out errors in a disc drive is disclosed. The compensation is created by determining transfer function values for a servo loop in the drive as well as a sequence of repeatable run-out values for a portion of a disc. The repeatable run-out values are divided by respective transfer function values to produce compensation values that are inverse transformed to produce time-domain compensation values. These time-domain compensation values are injected into the servo loop to compensate for repeatable run-out errors.

Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.

Abstract: An apparatus and associated method used to control a disc drive having at least one disc and a transducer positionable relative to the disc by a motor. The motor receives energization through at least one power switch integrated on a semiconductor circuit. Temperature of the circuit is sensed proximate the power switch. A temperature signal is provided which is indicative of whether the sensed temperature meets one of a plurality of different threshold temperatures. The power switch is controlled in one of a plurality of different control modes based upon the temperature signal.

Abstract: A method, apparatus, and computer program product for a hard disk drive servomechanism. In one embodiment, the apparatus comprises a disk which has a surface, a spindle motor that rotates the disk, a transducer which can write information onto the disk and read information from the disk, and an actuator arm that can move the transducer across the surface of the disk. The apparatus further includes a controller. The controller can determine a seek length from a first track to a second track, determine a seek time based on the seek length, scale the seek time in response to a velocity error between a calculated velocity and a design velocity for the seek length, and control the actuator arm to move the transducer across the disk surface from the first track to the second track using an acceleration trajectory.

Abstract: A disc drive including a rotatable data track, a dual-stage actuator with a primary actuator motor supporting an actuator arm, a read/write head supported by the actuator arm and communicating with a secondary actuator motor, and steps for controlling range of motion of the secondary actuator motor. The controlling steps include supplying and sustaining a bias signal to a single-sided unipolar device driver that then apply a bias voltage the secondary actuator motor to induce the secondary actuator motor to expand substantially one half of its expansion capabilities. And, confining correction signals provided by a control circuit of the disc drive, used in correcting mechanical position of the secondary actuator motor, to a voltage ranging substantially between a positive “+” and negative “−” voltage substantially equal to the applied bias voltage.

Abstract: The present invention relates to an information providing system. More particularly, this invention relates to an information management apparatus capable of reliable management of distributed information and an information providing system employing the same information management apparatus. The information management apparatus comprises a main information reproducing means for reproducing main information recorded in a given recording medium; and a reproduction management means for managing the main information reproducing means for reproducing the main information. The present invention provides a receiving means provided with a means for recording distributed information and control information limiting the number of main information reproducing cycles on a recording medium, and a main information reproducing means provided with a reproduction disabling means for limiting the reproduction of main information.

Abstract: A disc drive comprises a drive motor mechanically coupled to a disc and a voice coil motor mechanically coupled to a read/write head on the disc. A power integrated circuit is electrically coupled to the drive motor and the voice coil motor. The power integrated circuit includes an integrated temperature sensor that provides a temperature output. A control circuit receives the temperature output and provides a voice coil motor control output to the power integrated circuit as a function of the temperature output.

Abstract: A method for writing servo patterns on at least one disc in a disc drive that has a first set of tracks and a second set of tracks on a major surface of the disc includes stepping between the tracks of the first set of tracks at a first constant angle, and stepping between the tracks of the second set of tracks at a second constant angle. Stepping between tracks in the first group or the second group includes selecting two adjacent tracks from either the first group of tracks or the second group of tracks, and determining the angle through which an actuator assembly must be rotated between the two adjacent tracks selected to produce a selected track pitch. The method produces a disc for a disc drive with a first set of tracks, and a second set of tracks in which the track pitch varies across the set of tracks.

Abstract: An apparatus and method for sensing the position of a read/write head or transducer carried by a microactuator at a distal end of a primary actuator in a head disc assembly of a disc drive. The position sensing system has a fixed member attached to the primary actuator and a moveable member attached to the fixed member by an attachment device. The attachment device permits the moveable member to move in relation to the fixed member along a predetermined pathway. A secondary voice coil motor (VCM) drives the movement of the microactuator via a VCM coil that is affixed to the moveable member, wherein a high frequency signal is applied to the VCM coil. At least one sense coil is attached to the fixed member and positioned near the VCM coil, such that the sense coil will receive a portion of the high frequency signal transmitted from the VCM coil through mutual magnetic coupling.

Abstract: A disk drive includes at least one disk having a disk surface and at least one transducer head for writing and/or reading data from the disk surface. The disk drive performs a power-saving idle operation including reducing a rotational speed of the disk, and continuously moving the transducer head at varying radial velocity components relative to the disk surface in a repeating sweeping pattern between a selected inner disk diameter and a selected outer disk diameter. The radial velocity components are varied as a function of the transducer head's radial position in relation to the disk surface, such as with a radial velocity idle sweep profile representing a relationship between the radial velocity component of the transducer head and its radial location relative to the disk surface that optimizes head-disk interaction (HDI) when the disk is rotating at a given reduced rotational speed.

Abstract: A disk drive utilizes a unique write condition for each of the transducers within the drive. Each write condition is determined based upon the specific properties of the corresponding transducer. The write condition information is preferably stored within a memory within the disk drive. When a write operation is performed, the appropriate write condition for the corresponding transducer is used to determine when to write data to the disk. A write condition will typically include one or more individual write criteria. For example, a write condition can specify a write threshold value to be used during a write operation. Similarly, a write condition can involve a combination of a write threshold and a radial transducer velocity. Other write criteria are also possible.

Abstract: Method and apparatus are disclosed allowing for velocity sensing using back EMF in a media drive. A back EMF sensing circuit is provided that generates a velocity signal proportional to the back EMF in the head arm actuator coil, which signal may be utilized to improve head positioning control capabilities.

Abstract: An information storage device includes a cradle which can removably receive a cartridge that contains a rotatable hard disk. A read/write head is supported for movement adjacent the disk by a pivotal actuator arm. The cradle controls alignment of the head with the disk using feedback servo tracking. Servo parameters needed by the cradle to perform this tracking may be stored in a special wide track which is on the disk, and which may be a read-only track. Alternatively, the track may store updated firmware that can be loaded into the cradle. One approach to reading this special wide track is to effect servo tracking using default servo parameters. A different approach is to bias the actuator arm against a mechanical stop.

Abstract: An information storage apparatus that adjusts to different recording densities of a recording medium. The information storage apparatus includes a flash ROM that stores a plurality of control parameters corresponding to different recording densities, and a micro-controller unit (MCU) that sets one control parameter among the plurality of control parameters stored in the flash ROM, determines whether the set control parameter is suitable for reading data from the recording medium, and selects the control parameter determined to be suitable.