Abstract: Write pointer management for a disk drive including a disk having a plurality of sectors and a non-volatile memory (NVM) for storing data. Data is sequentially written sector by sector on the disk. The data written in a sector includes a write status indicator indicating that data has been written in the sector. A write pointer is stored on the disk or the NVM as a check-pointed write pointer. The write pointer corresponds to a current sector for writing data on the disk. During a write pointer recovery process, the check-pointed write pointer is retrieved, and at least one write status indicator is scanned in a range of sectors from the sector corresponding to the retrieved check-pointed write pointer and a last sector to identify the current sector for writing data. The write pointer is set to correspond to the identified current sector.

Abstract: A device comprises a first storage media and a controller. The controller configured to generate a first operational metric using a first set of operational data at a first frequency and a second operational metric a second set of operational data at a second frequency different than the first frequency; receive a write command to write data to the first storage media; and divert the write command to write data to a second storage media instead of the first storage media when at least one of the first operational metric and the second operational metric indicates that writing data to the first storage media may be harmful to the magnetic rotating disk or result in data loss.

Abstract: An apparatus includes: a media; a head configured to write data on the media; a read channel, coupled to the head, configured to detect servo data from the media; and control circuitry, coupled to the read channel, configured to: generate a position error signal (PES), associated with a write operation of an aggressor track, from the servo data, compare a first threshold to the PES for detecting a write unsafe condition, compare a second threshold, within the first threshold, to the PES for detecting a write squeeze condition, and control a refresh operation of a victim track based on at least one of the comparisons.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein at least two of the tracks comprise a thermal asperity. Prior to seeking the head from a first track to a second track, for each of at least two of the thermal asperities a minimum seek delay and a maximum seek delay that will cause the head to miss the thermal asperity are computed, and an allowed seek delay range that will cause the head to miss the thermal asperity is computed. When the undelayed seek will cause the head to hit at least one thermal asperity, the seek is delayed by a seek delay determined based on the minimum seek delays, the maximum seek delays, and the allowed seek delay ranges.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. First data is written to a first data track, and the first data is read from the first data track to measure a first quality metric representing a recording quality of the first data. Second data is written to a second data track, and the second data is read from the second data track to measure a second quality metric representing a recording quality of the second data. The first and second quality metrics are processed to generate a first statistical quality metric. A first defect threshold is generated based on the first statistical quality metric, and at least part of the disk is scanned for defects based on the first defect threshold.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. A defect scan of at least one of the tracks is executed, and a log entry is generated when a defect is detected. After the defect scan, a verify operation is executed for at least two of the detected defects. A number of times the verify operation detects a false defect is counted, and whether the head is defective is determined based at least partly on the count.

Abstract: An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein each track comprises a plurality of data sectors. A test pattern is written to at least one data sector in at least one track, and the test pattern is read from the disk to generate a noisy read signal comprising added noise. An estimated data sequence is detected from the noisy read signal, and an amplitude of the added noise is increased until a failure detection metric reaches a metric threshold. A failure threshold is generated based on the amplitude of the added noise when the failure detection metric reaches the metric threshold, and a failure condition of the disk drive is predicted based on the failure threshold.

Abstract: A data storage device can include a magnetic rotating disk, a solid state memory, and a controller. The controller is configured to generate a first operational metric which is updated at a first frequency and a second operational metric which is updated at a second frequency different than the first frequency, receive a write command to write data to the magnetic rotating disk, and divert the write command to write data to the solid state memory instead of the magnetic rotating disk when at least one of the first operational metric and the second operational metric indicates that writing data to the magnetic rotating disk may be harmful to the magnetic rotating disk or result in data loss.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by full sectors and intervening short servo sectors, where each full servo sector comprises a preamble, a sync mark, and servo bursts, and each short servo sector comprises a reference pattern and servo bursts. A first phase error is generated based on the sync mark in a first full servo sector, and a disk locked clock is adjusted in response to the first phase error. A second phase error is generated based on the reference pattern in a first short servo sector, and the second phase error is processed to determine whether the disk locked clock slipped a cycle before the head reaching the first short servo sector.

Abstract: A disk drive is disclosed comprising a disk comprising a plurality of data tracks, and a head actuated over the disk, the head comprising an asperity sensor operable to generate a sensor signal having a magnitude based on a bias setting of the asperity sensor. The asperity sensor is configured with a first bias setting and a first asperity on the disk is detected based on the sensor signal generated at the first bias setting. The asperity sensor is configured with a second bias setting different from the first bias setting and a second asperity on the disk is detected based on the sensor signal generated at the second bias setting.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, the head comprising a touchdown sensor comprising a resistance. A bias signal is applied at a reference value to the touchdown sensor at a reference temperature, and a corresponding reference resistance of the touchdown sensor is measured. An operating value for the bias signal is generated based on a predetermined operating temperature of the touchdown sensor, the reference resistance, the reference temperature, and a thermal coefficient of resistance (TCR) of the touchdown sensor, wherein the TCR specifies a change in temperature of the touchdown sensor relative to a change in the resistance of the touchdown sensor.

Abstract: A method to enable defect margining of a disk drive may comprise executing a data access command on a target sector on the disk drive. Upon encountering a data access error at the target sector, an address of the target sector may be added to an error list. The address of the target sector in the error list may then be converted to a physical location on the disk drive. A thermal asperity scan may be performed at and around the physical location and, upon detecting a thermal asperity, and at least sectors around the detected thermal asperity may be margined, and the data stored within the margined sectors may be relocated. Instead of sectors, entire tracks may be margined and the data stored therein relocated to a spare or reserve location, one track at a time.

Abstract: Systems and methods for performing refresh operations using write/read commands are provided. In one embodiment, a disk drive comprises a disk partitioned into a plurality of refresh zones, a head configured to write data to and read data from the disk, and a controller. The controller is configured to receive an access command, to read data from at least one of the refresh zones using the head in response to the access command, to check a condition of the read data, and to determine whether to refresh the at least one refresh zone based on the condition of the read data, wherein the read data includes data from a portion of the at least one refresh zone not being accessed by the access command.

Abstract: A storage device comprising a storage media and a controller is disclosed. The controller is configured to receive access commands from a host, to write data to or read data from the storage media based on the access commands, to detect a trigger event, and, when the trigger event is detected, to throttle back the access commands from the host based on an amount of data in a cache.

Abstract: A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors. A head is actuated radially over the disk for generating a read signal. A first read of a data sector is performed while adjusting an amplitude of the read signal in response to a gain control setting. When an error occurs while attempting to first read the data sector, a first jog value is generated in response to the gain control setting. The head is served over the data sector in response to the first jog value, and a second read of the data sector is performed.

Abstract: A disk drive is disclosed comprising a disk having a plurality of data sectors, wherein a physical block address (PBA) is associated with each data sector. When a write command is received from a host to write user data to the disk, and the write command comprises an unformatted logical block address (LBA), the user data is written to a first data sector, and the first data sector is write verified. A second data sector is defect scanned, and after the second data sector passes the defect scan, the user data is migrated from the first data sector to the second data sector and the LBA is formatted to the second data sector.

Abstract: A disk drive is disclosed having a first disk surface, and a head actuated over the first disk surface. The first disk surface comprises a plurality of servo tracks and a plurality of data tracks. The data tracks of the first disk surface are banded together into a plurality of data zones, including a first data zone and a second data zone. A first servo tracks per inch (STPI) to data tracks per inch (DTPI) ratio of the first data zone is substantially different from a second STPI to DTPI ratio of the second data zone.

Abstract: A disk drive is disclosed comprising a disk having a plurality of data sectors, and a head actuated over the disk. The disk drive further comprises control circuitry operable to execute a write operation for writing data to the disk. A first part of the data is written to a first data sector together with a first sector signature data (SSD) record comprising a first parameter of the write operation and a first id that identifies the first parameter. A second part of the data is written to a second data sector together with a second SSD record comprising a second parameter of the write operation and a second id that identifies the second parameter.

Abstract: Disclosed is a disk drive to characterize misaligned servo wedges. A disk of the disk drive includes a plurality of circumferential tracks, in which, each track includes a plurality of servo wedges spaced sequentially around the circumference of the track wherein the servo wedges may be misaligned relative to the head of the disk drive that moves about a pivot. A servo controller is used to characterize the misaligned servo wedges relative to the head during a seek operation by implementing the following operations: commanding the head to perform a seek operation from a starting track to an ending track; obtaining samples of wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges for sampled tracks traversed during the seek operation; calculating WTWT variations for each sample; and calculating a calibrated misalignment value for each sample based upon WTWT variations.