Abstract: A hard disk drive that stores data on a disk. An overshoot duration is used to write data onto the disk. The value of the overshoot duration is a function of the data rate, which can vary for different areas of the disk. For example, the data rate can be higher at an outer diameter of the disk than at an inner disk diameter. The overshoot duration can therefore be different when writing data at the outer diameter than the duration used to write data at the inner diameter. The data rate can be determined by analyzing a preamble of the data written onto the disk.

Abstract: A control system is configured to receive an input signal. The control system includes a control module to generate an output signal that tracks the input signal to the control system. The output signal includes a repeatable disturbance component. A compensation module is configured to receive an error signal. The error signal corresponds to a difference between the input signal and the output signal. The compensation module is configured to generate an estimate of the repeatable disturbance component based on the error signal, and to combine the estimate with the input signal to compensate for the repeatable disturbance component associated with the output signal.

Abstract: A testing apparatus for magnetic recording medium and a testing method for magnetic recording medium is provided. Such a testing apparatus for magnetic recording medium, including: a rotary mechanism which causes synchronous, coaxial rotation of a master medium and a subject medium; a first support arm; a second support arm; a head stack assembly which causes synchronous movement of a first magnetic head and a second magnetic head by causing synchronous, coaxial rotation of the first support arm and second support arm, and which determines the position of the second magnetic head relative to the subject medium based on servo information signals obtained by loading servo information from the master medium into the first magnetic head; and a signal processing mechanism which synchronizes the servo information signals and magnetic recording playback signals, and which tests the magnetic recording playback signals of the subject medium.

Abstract: In a method for providing an estimate of a head position for a disk drive, a readback signal is filtered. The readback signal includes a first position signal component corresponding to a first position pattern on a disk, and includes a second position signal component corresponding to a second position pattern on the disk. Filtering the readback signal includes using a filter determined based on statistical information regarding a noise component of the readback signal. An estimate of an amplitude of the first position signal component is generated based on the filtered readback signal, and an estimate of an amplitude of the second position signal component is generated based on the filtered readback signal. An estimate of a head position with respect to a track on the disk is generated based on the estimate of the amplitude of the first position signal component and the estimate of the amplitude of the second position signal component.

Abstract: A method for writing data to a tape at multiple rates for simultaneously creating data tracks having differing linear data densities, according to one embodiment, includes passing a tape over a head, the head having an array of writers thereon; receiving incoming data; mapping the data to a two dimensional array corresponding to the array of writers; clocking some of the mapped data to a first writer in the array of writers at a first rate; and clocking some of the mapped data to a second writer in the array of writers at a second rate different than the first rate.

Abstract: A recording medium storing information indicating that linking is applied immediately after the defective area, distinguishing a linking type which occurs in a general incremental recording mode from a linking type which occurs after the defective area. Defective areas are detected and registered in a predetermined area (recording management data (RMD) area) before user data is recorded or while user data is being recorded in the recording medium having a plurality of continuous basic recording units, such as a digital versatile disc-rewritable (DVD-RW) in which recording and reproducing can be done repeatedly. Linking is not only applied in an incremental recording mode or in a restricted overwrite recording mode, but linking is also applied to an area immediately after the defective area which is registered in the defect list, increasing reliability of the user data.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk having a plurality of data tracks, wherein a first plurality of data tracks comprises a first plurality of defect scanned data sectors and a second plurality of data tracks comprises a second plurality of unscanned data sectors. The second plurality of data tracks is divided into a plurality of defect zones. A first number of write commands are received from a host to write data to a first defect zone. A first data sector in the first defect zone is defect scanned in response to the first number of write commands to the first defect zone.

Abstract: Various embodiments of the present invention provide systems and methods for reducing head distortion. For example, various embodiments of the present invention provide storage devices that include a storage medium, a read/write head assembly, and an adaptive distortion modification circuit. The storage medium includes information that may be sensed by the read/write head assembly that is disposed in relation to the storage medium. The adaptive distortion modification circuit receives the information sensed by the read/write head assembly and adaptively estimates and implements a distortion compensation factor in the analog domain. In some instances of the aforementioned embodiments, the read/write head assembly includes a magneto resistive head. In such instances, the distortion compensation factor is designed to compensate for non-linear distortion introduced by the magneto resistive head.

Abstract: The present invention enhances the capability to specify a recorded position of designated data, even when a tape medium is run at high speed. A controller of a tape drive includes: a data set generator for generating a data set; a metadata generator for generating metadata including the number of records in the data set and the like; and a writing unit for writing the data set to the tape medium with a high recording density, and writing the metadata to the tape medium with a low recording density. The controller also includes: a movement controller for receiving a record number of a designated record; a reading unit for obtaining the number of records and the like included in the metadata read by running the tape medium at high speed; and a comparison unit for determining whether or not to read the data set by lowering the speed of the tape medium to R/W speed, in comparison with the record number received by the movement controller and the number of records and the like obtained by the reading unit.

Abstract: A system and method for determining the value of a longitudinal position (“LPOS”) bit of a storage medium. A system comprises a selector that selects a value for a longitudinal position (“LPOS”) bit from a plurality of possible values derived from LPOS information read from a storage medium. A quality determiner that determines a quality value for each of a plurality of LPOS values derived from the LPOS information. The selection of the value for the LPOS bit is based, at least in part, on the quality values.

Abstract: A method according to one embodiment includes generating a first gain error, comprising: receiving an output of an equalizer; and comparing a magnitude of the output to a saturation threshold level; if the output is higher than the saturation threshold level, generating a first gain error. The method further including generating at least one of a second and a third gain error, wherein generating the second gain error comprises: using either a slicer or a trellis for generating the second gain error, wherein the slicer generates a gain error based on an output of an interpolator, wherein the trellis generates a gain error based on an output of a maximum likelihood detector; wherein generating the third gain error comprises: receiving an output of an equalizer; generating a threshold qualified peak from the equalizer output and a tracking threshold level; comparing the threshold qualified peak to a second threshold; and generating a third gain error based on the comparison.

Abstract: Monitoring of the eccentricity of a pre-formatted servo pattern on a disk.

Abstract: Various embodiments of the present invention provide systems and methods for equalizing an input signal. For example, various embodiments of the present invention provide a method for performing equalization in a storage device. Such methods include providing an equalizer circuit that is governed by a target value, and a filter circuit that is governed by a filter coefficient. An initial value is provided to the equalizer circuit as the target value, and an overall target based at least in part on the initial value and the filter coefficient is calculated. An updated value is calculated based on the overall target, and the updated value is provided to the equalizer circuit as the target value.

Abstract: An apparatus and a method of detecting an error symbol in a data storage apparatus so that an error correcting performance of an error correction decoder.

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: A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble comprising a varying length across a radius of the disk, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. The tilt angle varies across the radius of the disk commensurate with the varying length of the preamble. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.

Abstract: An apparatus for writing data to a data storage medium on which data is stored in data groups (N?3 to N+1) comprising tracks extending across and spaced from a reference edge of the storage medium includes a control system operable to cause i) a track reference difference value representative of a difference in a distance between the tracks of an existing data group (N?1) on the storage medium and the reference edge and a distance between the reference edge and the tracks of a data group (N) to be written to the storage medium such that it is the next data group following the existing data group (N?1) or ii) data from which such a difference value can be derived to be included in at least one of frame (A1 to A5) to be written between the existing data group and the next data group such that the tracks of the at least one frame are spaced from the reference edge by substantially the same distance as the tracks of the existing data group.

Abstract: Among other disclosed subject matter, a magnetic disk controller can include an index detecting unit to detect an index of the magnetic disk, an error check code generating unit to, after the index detecting unit detects the index, generate a first error check code for first write data based on the first write data and a first physical address of a first sector subsequent to the detected index, and a writing control unit to cause the first error check code generated by the error check code generating unit, the first write data and the first physical address to be written into a second sector subsequent to the first sector.

Abstract: A triple track test for determining respective erase band widths associated with a read/write head involves writing first and second data tracks in each direction and at a certain distance from an origin, and erasing a track having a center at the origin. Based on a triple track test profile (3T) corresponding to the three tracks, a first distance is measured in one direction from the origin to one of the modified data tracks and a first erase band width is computed based thereon. The other side erase band width is computable similarly. A side erase amplitude loss measurement procedure, for determining the amount of signal amplitude lost by an adjacent track due to the respective erase bands, involves constructing a side-erase profile based on a composite of the 3T profile and a full-track profile, from which respective amplitude losses are computed for the respective erase bands.

Abstract: A storage medium having a boundary located along a surface of the storage medium that functions as a transition point for selectively operating a first writer and a second writer of a plurality of writers, where the location of the boundary is set based on writing capabilities of the plurality of writers.