Abstract: A method of manufacturing a disk drive and a disk drive made with such method where the width of the read element and the width of the write element are both measured at servo-writing time and the track pitch of the disk drive is set on the basis of those measurements. Disk drives with superior head width combinations are servo-written with a narrower track pitch in order to have a higher storage capacity. Disk drives with inferior head width combinations are detected before servo-writing so that the disk drive may be servo-written with wider track pitch rather than with a nominal track pitch that results in a subsequent drive failure during initial burn-in (IBI). The heads are used more efficiently in that heads that are more capable are used to their ability and less capable heads that would otherwise be disposed of are used at all. Fewer disk drives are required to be reworked and returned to the servo-writing process.

Abstract: A band of data storage tracks adjacent to an initial OD (outer diameter) limit are analyzed to determine a track defect density based on flagged tracks within the band. If the defect density exceeds a predetermined threshold, them the disk drive is reconfigured by adjusting initial OD and ID (inner diameter) limits to exclude the analyzed band and to maintain a targeted storage capacity. Adjusting the initial OD and ID limits improves the disk drive's seek performance which would otherwise be disproportionately impacted by the defect density in the analyzed band.

Abstract: Methods and devices for converting the kinetic energy of the rotating spindle motor of a disk drive of a rechargeable battery operated mobile host device into electrical energy during braking of the rotating spindle motor. The converted electrical energy is conditioned and used to charge the rechargeable battery of the mobile host device.

Abstract: Disclosed is a disk drive cover that provides improved disk shrouding and heat dissipation. Part of the cover is recessed relative to the rest and may be substantially circular. The recessed portion may be located approximately adjacent to at least one disk and may be substantially coextensive with at least one disk. Further, the internal side of the recessed portion may be at a vertical depth sufficient enough to shroud at least one disk. Additionally, the recessed portion may further include at least a member that projects from the external side of the recessed portion, such as approximately arcuate-shaped members or approximately rectangular-shaped members, to aid in heat dissipation.

Abstract: A rotating media storage device (RMSD) includes a disk having at least one track with a plurality of servo wedges, a moveable head, and a microprocessor. The microprocessor receives a plurality of position error signal (PES) values during track following and sums PES values for a plurality of different sets of servo wedges of the track to generate a plurality of shifted summed position error signal (SSPES) values. The microprocessor shifts the plurality of generated SSPES values by a phase shift value to generate a plurality of corrected shifted summed position error signal (CSSPES) values, which correspond to the repeatable runout (RRO) of the disk.

Abstract: A production line spindle control circuit is disclosed for use in manufacturing a disk drive. The production line spindle control circuit generates sinusoidal driving currents applied to a spindle motor of the disk drive, and processes a back EMF signal generated by the spindle motor in order to control a commutation sequence as well as the angular velocity of the spindle motor. The production line spindle control circuit is attached to the spindle motor during a manufacturing procedure, such as servo writing, and detached from the spindle motor after the manufacturing procedure.

Abstract: A method and an apparatus for reducing position error signal in a disk drive, which has an actuator and a magnetic medium, write the servo tracks with a servo track writer using a varying increment. The servo tracks are written after the servo track writer incrementally moves the actuator by a non-constant amount. The non-constant incrementing enables a servo track writing operation to write servo tracks that are at least as wide near the outer circumference as they are near the zero skew position or near the inner circumference.

Abstract: A population of disk drives includes a first disk drive configuration that has a spindle motor made according to the spindle motor design and a second disk drive configuration that has a spindle motor made according to the spindle motor design. A population of spindle motors are manufactured according to a spindle motor design. Each of the spindle motors in the population of spindle motors has a track-following characteristic in a range. A first group of spindle motors that correspond to a first portion of the range are allocated to the first disk drive configuration. A second group of spindle motors that correspond to the second portion of the range are allocated either to the second disk drive configuration or to the first disk drive configuration.

Abstract: A method of expanding the on-track operational range of a disk drive based upon detection of an external vibration condition. The method involves detecting that a vibration state exists and, while the existence of the vibration state is detected, modifying the default on-track-declaration algorithm such that a data transfer operation can be completed in less time than if the default on-track-declaration algorithm was in use.

Abstract: A method and an apparatus select the operational spindle rotation rate for a disk drive 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, an operational spindle rotation rate is selected for use when the head-disk assembly is combined with a controller to produce a disk drive.

Abstract: An aspect of the invention can be regarded as a disk drive that includes a disk drive base and a spindle motor hub rotatably coupled to the disk drive base. The disk drive further includes a first disk disposed about the spindle motor hub and having a first disk stiffness. The disk drive further includes a second disk disposed about the spindle motor hub and having a second disk stiffness different than the first disk stiffness. According to another aspect of the present invention, the second disk has a second disk thickness different than a first disk thickness. According to another aspect of the present invention, the second disk is formed of a second material having a second material stiffness different than a first material stiffness.

Abstract: Disk drives are produced having a track density that is determined during a servo-track writing operation. A plurality of calibration tracks is written onto a storage medium of a disk of a head-disk assembly at a calibration track density. The calibration track density corresponds to a portion of a nominal track density profile. An aspect of the servo performance of the head-disk assembly is measured at the calibration tracks. A selected track density profile is identified based on the measured servo performance. The plurality of tracks is written to storage medium at the selected track density profile.

Abstract: A hard disk drive that determines a saturation current of a voice coil motor (VCM) during the acceleration portion of a seek operation, and uses the information to advantageously adjust current profile for subsequent portion of the seek. One example of determining the saturation current is utilization of the peak value of the saturated acceleration current whose magnitude depends on operating conditions such as temperature and supply voltage. Traditional hard disk drives use predetermined seek current profiles that are formed conservatively to account for such variations in the available current to the VCM, at the expense of sacrificing some seek performance. By determining the available current for each seek operation, the current profile can be adjusted on the fly so as to improve the seek performance.

Abstract: A method and system are described for preventing data loss from an off-track write condition in a disk drive. In accordance with exemplary embodiments of the present invention, the disk drive comprises a disk surface comprising a first track and a second track adjacent to the first track, and a head for writing data to and reading data from the first and second tracks. The method of recovering from the off-track write condition comprises the steps of receiving a write command to write a first series of data blocks on the first track. Before writing the first series of data blocks, a second series of data blocks stored in the second track is read and stored in a data buffer.

Abstract: A rotating media storage device (RMSD) includes a cache memory and a microprocessor for executing a read caching algorithm for storing data in the cache memory. The microprocessor modifies the read caching algorithm when a vibration state is detected to optimize data transfer rates to and from the media in a vibrating operational environment.

Abstract: A disk drive having a marker for identifying the transition between the first and last written servo wedges on a servo track. The marker indicates the likely position where closure error may occur during the operation of the hard disk drive. The marker is used by the control system of a hard disk drive to provide appropriate position control signals to the transducer assembly to maintain the proper positioning of the transducer about the disk surface. A method for forming the marker on a disk surface is further disclosed.

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 disk drive control system that compensates for mechanical bias torques present in disk drives. A transducer, commonly referred to as a head, is attached to an actuator arm that is subjected to mechanical bias torques, including flex bias torque and bearing friction. The net bias torque has a mechanical memory that is manifested as hysteresis whose magnitude depends on the size of the stroke length between inflection points of the transducer in seek operations. The dependence of the net bias torque includes location of the transducer, direction of the seek, and the history of previous seeks. The dependence may further include operating temperature of the disk drive. The disk control system determines and applies these corrections to the disk drive to enhance the seek performance.

Abstract: The invention relates to a method for recovering from shock event to a disk drive. Embedded servo wedges are read to generate position error signal (PES) values. The disk drive is transitioned to a write unsafe state if a PES value is greater than a write unsafe (WUS) threshold and is less than a shock detection threshold. The disk drive is transitioned to a shock recovery state if a PES value is greater than the shock detection threshold. The disk drive is transitioned from the shock recovery state to the write unsafe state if a first number of consecutively generated PES values remain less than the WUS threshold. The disk drive is transitioned from the write unsafe state to the on-track state if a second number of consecutively generated PES values remain less than the arrival threshold, which threshold is less than the WUS threshold.

Abstract: A method is disclosed for seeking from first radial position on a spiral track of a magnetic disk drive to a second radial position. The disk having the spiral track rotates at a constant angular velocity. The servo sectors on the spiral track may not be aligned along a radius. A head transit time is determined for moving the head to the second radial position. A first control current pulse is applied to an actuator to move the head toward the second radial position. A timer is commenced for measuring the expiration of the head transit time after applying the first control current pulse. After expiration of the head transit time, a second control current pulse is applied to the actuator to terminate the head movement. At least one servo sector along the spiral track is then read to locate the position of the head.