84 results about "Track (disk drive)" patented technology

Disclosed are techniques related to cluster-based defect detection testing for disk drives. A disk drive comprises a disk, a moveable head to scan the tracks of the disk, and a defect detection circuit to detect defects on the disk scanned by the moveable head. The disk drive includes a microprocessor for controlling operations in the disk drive including cluster-based defect detection. The microprocessor under the control of a cluster detection program defines a scan window. The scan window corresponds to an area of the disk scanned by the moveable head. The microprocessor under the control of the cluster detection program further defines a cluster threshold corresponding to a minimum number of defects required to occur within the scan window and identifies a defect cluster if a cluster threshold of defects occurs within the scan window. By identifying defect clusters on the disk these defect clusters can be margined.

An optical data-storage hard disk drive, which uses stationary Magneto-Optical Microhead Array Chips in place of conventional Flying-Heads, Rotary Voice-Coil Actuators and other similar types of Servo-Tracking mechanisms to transcribe or retrieve digital information to or from at least one non-volatile memory medium's data-surface, using an optical magnetic process of recording and reading data. The Magneto-Optical Microhead Array Chip Hard Disk Drives will have at least one storage disk-platter with two disk-platter data-surfaces containing a multiplicity of concentric data-tracks that rotates at a substantially constant angular velocity. Every Magneto-Optical Microhead Array Chip will comprise a (VCSEL) "Vertical Cavity Surface Emitting Laser" microhead array having a minimum of one thousand or a maximum of four billion individually addressable VCSELs. Each Magneto-Optical Microhead Array Chip is placed into a stationary position above each disk platter data-surface using a chip-positioning circuit board. While the number of cylinder/tracks available to each Magneto-Optical Microhead Array Chip is determined by the number of VCSEL microheads contained within a Magneto-Optical Microhead Array Chip's microhead array (e.g., "325,000" vertical cavity surface emitting laser microheads would therefore equal "325,000" corresponding cylinder/tracks).

A method, system, and computer program product for mitigating adjacent track erasures in hard disks, includes: determining input/output (I/O) characteristics for a plurality of blocks on a hard disk; assigning the plurality of blocks to a plurality of categories of I/O characteristics by the processor; and clustering content of the blocks assigned to the same category in one or more continuous tracks on the hard disk. Each block is assigned to one category. Blocks with similar I/O characteristics are clustered on one or more continuous tracks. By performing this clustering, blocks with a high number of I/O operations are grouped and stored on fewer tracks than if they were scattered across numerous tracks. This reduces the number of tracks experiencing a high number of I/O operations, and in turn, the amount of refreshing of adjacent tracks is reduced.

A magneto-optical data storage hard disk drive that uses stationary "Light Intensity Modulated Direct Over-Writey" (LIMDOW) or "Magnetically induced Super Resolution" (MSR) "Magneto-Optical Microhead Array Chips' in place of conventional flying-heads, rotary voice-coil actuators, or other similar types of "servo-tracking' mechanisms to simultaneously record and/or reproduce data to and/or from a multitude of data-tracks located across the data-surfaces of a multitude of LIMDOW or MSR disc media that comprise two or more different coercive force regions at room temperature, using a multitude of microheads.

A method of reducing microjog errors in a disk drive having a data recording disk with data tracks and a transducer head positionable on the tracks. The head includes a writer element offset from a reader element. To reduce microjog errors, track squeeze is measured at a number of locations across the surface, wherein the squeeze is due to mis-positioning of the track relative to neighboring tracks. A microjog distance for the destination track is provided, and a microjog correction value based on the measured track squeeze is calculated. The correction value is applied to the microjog distance to obtain a corrected microjog distance that reduces microjog errors due to track squeeze.

A disk drive self-servo writes on a storage disk. Servo bursts are self-written along a track using a transducer, a position error signal (PES) indicating repeatable runout due (RRO) for the servo bursts is determined using a reference pattern, an embedded runout correction (ERC) value is calculated based on the PES and stored in a corresponding servo sector, and then the disk drive self-writes other servo bursts.

Storage architecture for bit patterned media uses both erase band and shingled magnetic recording. A hard disk drive may comprise a disk having bit patterned media with a plurality of data tracks arrayed in architecture pages having at least one of erase band mode (EBM), shingled mode (SM) and unallocated space. An actuator has a head for writing data to the data tracks of the bit patterned media. A control system monitors, reallocates and reconfigures the architecture pages from EBM, SM or unallocated space to a different one of EBM, SM or unallocated space to enhance performance of the hard disk drive.

A shingled magnetic recording hard disk drive that uses writeable cache tracks in the inter-band gaps between the annular data bands minimizes the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing to the cache tracks. Based on the relative FTE effect for all the tracks in a range of tracks of the cache track being written, a count increment (CI) table or a cumulative count increment (CCI) table is maintained. For every writing to a cache track, a count for each track in an adjacent boundary region, or a cumulative count for each adjacent boundary region, is increased. When the count value for a track, or the cumulative count for a boundary region, reaches a predetermined threshold the data is read from that band and rewritten to the same band.

A method of defining storage format in a data storage device having a plurality of storage media and a plurality of corresponding data transducer heads, each transducer head for recording on and playback of information from a corresponding storage medium. A storage format is defined in at least one region on each storage medium, wherein each region includes a plurality of concentric tracks for recording on and playback of information. The method includes: moving each storage medium with respect to the corresponding transducer head and reading data from each storage medium with the corresponding transducer head; measuring a record/playback performance capability of each transducer head; selecting a group of track densities, one track density for each region on a storage medium, based on the measured record/playback performance capability of the corresponding transducer head.

Servo tracks are written onto different disk surfaces using multiple recording heads within a disk drive without requiring a servo writing machine or clean room conditions. Microactuators in the reference heads in the disk drive are capable of independent motion with respect to one another, which allows the servo tracks to be written to the disk surfaces. The process begins as the recording heads are biased against a crash stop, and then moved to an adjacent track. One of the heads writes a reference track at this adjacent track position when a microactuator of the head is centered. This reference head then follows the reference track with its microactuator centered, while the other recording heads move in the radial direction to write servo information on their respective tracks. Reference tracks are then successively used to write the servo information as the recording heads move in a direction away from the crash stop.

A patterned-media magnetic recording disk drive compensates for circumferential misalignment of data island patterns among the data tracks as a result of errors in fabrication of the master template used to make the disks. Each data track on the disk has its pattern shifted from a generally radial or arcuate line by a certain amount of pattern circumferential misalignment (PCM). The disk drive includes a write clock where writing to the data islands is controlled by detection of synchronization marks by the read head, and circuitry to adjust the phase of the write clock to compensate for PCM. The phase difference between the data pattern of the selected data track where data is to be written and the data pattern of the track where the synchronization marks are being detected is the difference in their respective PCM values.

Methods and apparatus are provided for creating servo-tracks on the R-side of single-sided hard memory disks. The method includes placing two single-sided disks in a concentric contact merge orientation with the R-side of each disk facing outwardly. Two independent servo-track writers then position an independent transducer proximate each R-side and write desired servo-track data to the R-side surface of each disk. The disks are de-merged and either disk may be placed in any single-sided disk drive.

A thermally-assisted recording (TAR) disk drive that uses “shingled” recording and a rectangular waveguide as a “wide-area” heat source includes a controller that counts the number of writes to each annular band of data tracks. The wide-area heater generates a heat spot that extends across multiple tracks, so that each time an annular band is written, the data in tracks in adjacent bands are also heated. Because the bands are written independently, the number of passes of the heat spot and thereby the number of times the data tracks in a band are exposed to elevated temperatures without being re-written is related to the number of re-writes of the adjacent bands. The number of writes to each band is counted and when that count reaches a predetermined threshold value, one or more tracks in an adjacent band are re-written to avoid reaching an unacceptable level of magnetization decay in the tracks of the adjacent band.

A patterned-media magnetic recording disk drive has compensation for write head track misregistration (TMR) from the track centerline. As the disk rotates, the read head detects angularly spaced servo sectors and generates a position error signal (PES) which is used by the servo control system to maintain the read head on track. As the disk rotates, the read head also detects angularly spaced synchronization marks, which are used to control the write clock so that magnetization reversal of the magnetic write field from the write head is synchronized with the position of the data islands. If there is TMR of the write head, there will be an effective shift of Δφ in the timing of when the center of the data islands pass through the write field. The disk drive includes write clock phase adjustment circuitry that correlates the PES with Δφ to compensate for TMR of the write head.

Disk drives, methods, and computer program products are provided for controlling seeking of a transducer that is adjacent to a rotatable data storage disk in a disk drive. The disk drive includes a secondary actuator for positioning the transducer over a second range of movement, and a primary actuator for positioning the secondary actuator over a first range of movement that is larger than the second range of movement. The secondary actuator is controlled to move the transducer toward a target track on the disk while seeking. The primary actuator is controlled to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to maintain the transducer on the target track.

A magnetic recording disk drive with rotational vibration (RV) cancellation uses the position error signal (PES) and the signal from a RV sensor to determine when to enable and disable RV cancellation. An RV feedforward compensation signal to be summed with the VCM control signal is “switchable”, meaning that it can be enabled or disabled by the disk drive servo control processor. The determination to enable or disable is made from a comparison of the PES with a threshold PES, which may be an estimate of the off-track position of the head calculated from the RV sensor signal. The estimated off-track is compared to the absolute value of the actual or measured PES. If the estimated off-track is smaller than the actual PES, then the state of the RV cancellation is switched, i.e., if it is enabled it is disabled and if it is disabled it is enabled.

Track pitch in a hard disk drive is selected to satisfy the requirements of both off-track capacity (OTC) and adjacent track interference (ATI). The invention separately measures the track pitch requirements for OTC and ATI. The track pitch for the drive is set with the larger of the OTC and ATI track pitches. The OTC track pitch is measured with a 747 curve, and the ATI track pitch is measured by the positions of adjacent tracks at which the on-track error rate is not worse than a given value after the targeted number of adjacent track writes in the ATI requirement.

A "snake-in-the-box" (SITB) code is used to encode a track identifier (TID) in a servo sector of a disk drive to identify a particular track on the disk surface. The SITB code describes the longest possible vector that can fit into a finite space, and comprises a type of difference-preserving code. When an SITB code is used for the TID, any single bit error in the TID will be detected. The Hamming distance for TIDs of adjacent tracks is 1 with a SITB code, as with a Gray code. However, for TIDs of tracks that are not adjacent, the Hamming distance is at least 2 with a SITB code.