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

To provide a magnetic disk device capable of predicting whether error correction to a data track of a disk reaches a limit or not.SOLUTION: A magnetic disk device 1 includes a first disk having a first data track and a second data track, a first write head, a write processing unit, an error correction unit, a correction limit prediction unit 65, and a determination unit. During the write period, the correction limit prediction unit 65 calculates the excess amount OVR, calculates the metric value Mer by multiplying the excess amount OVR by the first weighting factor, updates the cumulative metric value ME, and generates the first prediction information. The determination unit determines whether to cause the write processing unit to continue the write processing on the second data track based on the first prediction information.SELECTED DRAWING: Figure 18

Controlling a shingled magnetic recording (SMR) hard drive involves attempting a sequential write to a first sector of a sequence of sectors and, responsive to encountering a write inhibit boundary corresponding to the first sector, continuing the write to the next available sector in the sequence of sectors for the write. Thus, instead of that write inhibit triggering a hard error, the data is adaptively written to the next down-track physical sector possible, i.e., “sliding” to the next sector. This does not require an additional disk revolution thus there is negligible performance penalty. The write may be continued to the next track if necessary, and may continue through the entire zone, to maintain all the data in sequential form for performance and large block protection purposes.

To accurately detect read errors in postcodes. [Solution] The magnetic disk device of the embodiment comprises a magnetic disk having a plurality of tracks, a magnetic head for reading and writing data to the magnetic disk, a plurality of servo regions provided on each of the plurality of tracks and including at least a portion of a first physical pattern which is the physical pattern after writing of a first data pattern including position information for each of the plurality of tracks, and a control unit for controlling the magnetic head. Each of the plurality of servo regions includes either a first servo region including the first physical pattern, or a second servo region including a second physical pattern which is the physical pattern after writing of a second data pattern different from the first data pattern, for each of the plurality of tracks, and the control unit determines whether the third servo region among the plurality of servo regions of the plurality of tracks has the first or the second physical pattern.

To provide a magnetic disk device having high performance of write operation.SOLUTION: The controller executes the determination operation as the magnetic head passes through the servo sector during the write operation. In the determination operation, the controller calculates a first cumulative amount obtained by accumulating, in a first section, an evaluation amount corresponding to an amount by which the width of the adjacent track is narrowed by the write operation, and determines whether the first cumulative amount is smaller or larger than a threshold value corresponding to a correction limit of error correction in units of tracks. The first period includes a second period in which writing of data is completed and a third period in which data is written following the second period. The controller performs a write operation in response to determining that the first cumulative amount is larger than the threshold value by the determination operation, executes a rotational delay, and then re-executes the determination operation. The controller resumes the write operation in response to determining that the first cumulative amount is smaller than the threshold value by the re-executed determination operation.SELECTED DRAWING: Figure 9

Properly controlling the operation of the magnetic head. [Solution] In the magnetic disk device of the embodiment, the controller, while writing to the first track among the plurality of tracks, determines using a determination model whether the position of the magnetic head moves from the target position on the first track to the side of the second track which is different from the first track among the plurality of tracks, and whether the radial distance from the target position to the position of the magnetic head exceeds a threshold. If the distance does not exceed the threshold, the controller performs writing to the first track, and if the distance exceeds the threshold, the controller does not perform writing to the first track. The determination model is a trained model that takes multiple position error information obtained by reading the servo information from each of the plurality of servo regions as input and outputs whether the distance exceeds the threshold while the magnetic head moves through the plurality of servo regions.

To appropriately perform error correction.SOLUTION: According to one embodiment, in a disk device, a controller can perform error correction for each sector in units of tracks. The controller can predict that the number of error sectors of the second track reaches the correction limit number of sectors according to the track margin specified by the first management information and the off-track amount of the first track while writing data to the first track with the head. The first track is a track of the plurality of tracks. In the first management information, track identification information and a track margin are associated with each of the plurality of tracks. The second track is a track adjacent to the first track among the plurality of tracks. For each of the plurality of tracks, the controller updates the first management information according to the reference value of the bit error rate and the bit error rate of the information read from the track.SELECTED DRAWING: Figure 1

The invention provides a magnetic disk device capable of improving reliability. A magnetic disk device according to an embodiment includes: a disk; a head that writes data to the disk and reads data from the disk; a first sector group including at least one first sector capable of performing error correction processing in units of tracks on the basis of a first parity sector, and the first parity sector; and a second sector group including at least one second sector in which error correction processing in units of tracks cannot be performed.

To provide a magnetic disk device with a large storage capacity.SOLUTION: A magnetic head performs a magnetization operation to magnetize a magnetic disk with either a first polarity or a second polarity opposite to the first polarity. The magnetization operation includes a first magnetization operation to magnetize with a first recording width and a second magnetization operation to magnetize with a second recording width larger than the first recording width. A controller magnetizes a first area unit to either the first polarity or the second polarity in the first magnetization operation or the second magnetization operation, and then magnetizes a second area unit to the opposite polarity to the first area unit in the second magnetization operation. The second area unit is an area unit radially adjacent to the first area unit, included in a second track, which is adjacent to the first track among a plurality of tracks and written after the first track.SELECTED DRAWING: Figure 8

To provide a magnetic disk device having high performance of write operation.SOLUTION: The controller calculates an evaluation amount of damage received by the data of the adjacent track due to the write operation based on the position error signal, and compares a first amount, which is the evaluation amount calculated based on the position error signal, with a first threshold value corresponding to a correction limit of error correction in track units. The controller suspends the write operation in response to determining that the first amount is greater than the first threshold value. Then, the controller executes a read operation on the adjacent track, acquires a metric representing signal quality of the data of the adjacent track read by the read operation, calculates an evaluation amount based on the metric, and compares a second amount, which is the evaluation amount calculated based on the metric, with a first threshold value. In response to determining that the second amount is less than the first threshold value, the controller continues the write operation.SELECTED DRAWING: Figure 11

A disk drive device capable of improving reliability is provided. The disk drive device according to this embodiment includes: a disk having tracks including a first servo sector and a second servo sector different from the first servo sector; a head for writing data to the disk and reading data from the disk; and a controller that records first signal strength recording data associated with the signal strength obtained from reading first target servo data, and normalizes the first signal strength data associated with the signal strength obtained from reading the first target servo data when reading the first target servo data, wherein the first target servo data is the target servo data of the first servo sector.

To provide a magnetic disk device capable of suppressing performance deterioration caused by minute projections on a recording medium.SOLUTION: According to an embodiment, a magnetic disk device includes a magnetic head including a rotatable disk-shaped recording medium having a plurality of recording tracks, a write element which writes information to the recording tracks, a heating element, and a sensor which detects a surface state of the recording medium, and a controller including an inspection circuit which detects presence or absence of a bump on a surface of the recording medium and a height and a width of the bump based on a sensor output of the sensor, and a memory which records the detected height and width of the bump.SELECTED DRAWING: Figure 1

Embodiments of the present invention provide a disk drive with high recording quality. In the disk drive of the embodiment, the processing circuit modulates the recording width in the radial direction of the first data sequence according to a first combination and a second combination when writing data to the first track. The first track is a track adjacent to a second track, which is a track on which data has already been written. The first combination is a combination of the first data sequence as data written to the first track and the second data sequence as data already written to the second track. The second combination is a combination of the polarities of the bit positions of the first track and the second track, which are adjacent to each other in the radial direction.

Described are systems and methods during writing of data in hard disk drives in which adjacent track squeeze events are predicted by looking at the difference in position error signal (PES) between two tracks, one PES being a recorded value for data already written, and the other being a predicted value for an upcoming write. This approach recognizes that only using the PES of the track currently being written may not be a reliable indicator of sector failure, particularly in environments susceptible to vibration. This can reducing the unrecoverable error rate while maintaining in-system performance by stopping high-risk writes before they occur and by preventing unnecessary write fault flags.

Methods are provided for managing defects in Hard Disk Drive (HDD) storage devices. In particular, only a portion of the cylinders of an HDD is tested. A bag of machine learning models is used to reconstruct the data for the untested cylinders. A defect file for the HDD is generated, a classifier model may be applied to the defect file, and one or more neural network models may be applied. If the defects are unsuitable for use by the models, then a scan of the entire HDD is run instead. An HDD comprises a rotating disk and a read / write head actuated above the disk surface. The disk may be formatted into concentric data tracks, with each track being divided into sectors. The tracks may be organized into zones (groups of tracks called cylinders), and the axially parallel sectors in each cylinder may be organized into wedges.