Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator configured to control a fly height of the head over the disk. A plurality of host read commands are received from a host, and a performance metric associated with accessing the disk to execute the host read commands is measured. When the performance metric indicates the data storage device is operating with a performance margin, the fly height actuator is controlled to increase the fly height of the head over the disk, wherein the performance metric consists of at least one of a throughput of the host read commands and a power consumption of the data storage device.

Abstract: Embodiments described herein provide an apparatus that is operable with a disk drive. The apparatus includes a memory device operable to store a plurality of bit sets. Each bit set identifies a track and a sector of the disk drive and a number of times that the track of the disk drive has been written. A controller of the disk drive is operable to increment the number when the track is written. Each bit set comprises a number of bits that is established according to track location of the disk drive.

Abstract: Technologies are provided for partially updating shingled magnetic recording (SMR) zones in SMR storage devices. An SMR storage device can receive and process a command to update a write pointer for an SMR zone to point to an arbitrary write position within the SMR zone. A partial SMR zone update command can be received and processed to modify part of the data stored in the SMR zone. A write position within the SMR zone where data to be modified is stored can be identified. Data stored in the SMR zone following the identified write position can be read to a temporary location and modified. A write pointer for the SMR zone can be updated to point to the identified write position. The modified data can then be written to the SMR zone, starting at the write position identified by the write pointer, or to another SMR zone of the storage device.

Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the servo head is a TMR head, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.

Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the magnetic layer is 48.0° to 53.0°.

Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic hexagonal ferrite powder, non-magnetic powder, and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and a tilt cos ? of the ferromagnetic hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 0.95.

Abstract: The magnetic tape device including: a magnetic tape; and a servo head, in which the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.

Abstract: A data storage device is disclosed comprising a head actuated over a disk surface comprising a plurality of servo tracks, wherein the head comprises at least two read elements including a first read element and a second read element, and at least two of the read elements are offset radially relative to a center of the two read elements by at least a width of a servo track at all radial locations of the head over the disk surface. First servo data recorded in a first servo track is read using the first read element to generate a first read signal, and second servo data recorded in a second servo track is read using the second read element to generate a second read signal. The head is servoed over the disk surface based on at least the first read signal and the second read signal.

Abstract: A magnetic disk device includes a magnetic disk having a plurality of tracks, a magnetic head used for writing data on the magnetic disk and reading data from the magnetic disk, a controller configured to control seek operations of the magnetic head, and a vibration sensor. The controller predicts a first vibration caused by a currently executed seek operation, based on a seek control signal, predicts a second vibration based on vibration detected by the sensor, and determines an adjusted start time of the currently executed seek operation so that a phase of the first vibration does not match a phase of the second vibration.

Abstract: A driver device coupled to a winding of an electro-mechanical actuator includes: a power stage driving the winding in a discontinuous mode by alternating conduction on-phases to off-phases, and a sensor circuit sensing a voltage across the winding in an off-phase, wherein, during such an off-phase the voltage across the winding includes a residual voltage which decays to zero. The power stage drives the winding from an on-phase to an off-phase by applying to the winding a reverse current pulse to invert the direction of flow of the current through the winding and produce an oscillation of the residual voltage, whereby the residual voltage includes a zero-crossing point after the current through the winding is exhausted. The sensor circuit senses the voltage across the winding at this zero-crossing point, whereby the voltage sensed across the winding at the zero-crossing point is indicative of the back electromotive force of the winding.

Abstract: According to one embodiment, a position detecting device includes a detecting portion which periodically detects a plurality of pieces of information generated in accordance with positional information divided into upper digits and lower digits. The upper digits are further divided into a plurality of pieces of upper digit information equal to the number of the period. The pieces of the upper digit information are obtained in a predetermined order. The lower digits are obtained simultaneously with any one of the pieces of the upper digit information. The positional information is divided so that the number of values, which are obtainable in one piece of the upper digit information provided by dividing the upper digits, and a division number of the upper digits are coprime.

Abstract: A data storage device is disclosed comprising a first disk surface comprising a plurality of servo tracks, a first head actuated over the first disk surface, wherein the first head comprises a first read element, and a second read element. During a write operation first servo data in a first servo track is read using the first read element to generate a first read signal, and the first head is servoed over the first servo track based on the first read signal while writing data to the first disk surface. Second servo data is read using the second read element to generate a second read signal, and the write operation is aborted when the first read signal indicates a shock event is affecting the servoing of the first head and the second read signal confirms the shock event.

Abstract: According to one embodiment, a magnetic disk device including a disk, and a controller which calculates a first corrected value based on a first eccentricity of the disk, and writes a first track based on the first corrected value, wherein when the controller interrupts the process for writing the second track so as to overlap the first track at a first position, the controller measures a second eccentricity of the disk, and compares the first eccentricity with the second eccentricity, and when the first eccentricity is different from the second eccentricity, the controller restarts the process for writing the second track from a second position away from the first position in a radial direction.

Abstract: An apparatus includes voice coil motor (VCM) control circuitry and microactuator control circuitry. The VCM control circuitry includes a VCM disturbance observer configured to generate a VCM disturbance compensation signal. The microactuator control circuitry includes a microactuator disturbance observer configured to generate a microactuator disturbance compensation signal. The VCM disturbance observer and the microactuator disturbance observer are decoupled from each other.

Abstract: A method that includes supplying a predetermined signal to a write head having side shields. The method also includes performing, by the write head, a recording operation on a surface of a data storage medium, when the predetermined signal is supplied to the write head, to provide a recorded magnetization pattern. The method further includes carrying out measurements on a portion of the recorded magnetization pattern influenced by a magnetization of the side shields. The measurements are employed to determine whether a reversed side shield magnetization condition is present in the write head.

Abstract: An apparatus includes a first controller, a second controller, and a coupling compensator. The first controller is configured to generate a first voice coil motor (VCM) control signal in response to a first position error signal. The second controller is configured to generate a second VCM control signal in response to a second position error signal. The coupling compensator is configured to generate a first feedforward correction signal in response to the first VCM control signal. The first feedforward correction signal modifies the second VCM control signal to generate a modified second VCM control signal.

Abstract: A method according to one embodiment includes gathering information about how an array of writers write and/or are expected to write to a magnetic medium during shingled recording, and computing, using the gathered information, data describing a lateral writing position to use during writing such that shingled track edges are aligned according to a format. A method according to another embodiment includes obtaining a lateral offset from a nominal writing position, and applying the lateral offset for repositioning a writing position of an array of writers relative to a nominal writing position during writing in a first direction. A product according to one embodiment includes a magnetic recording medium; and data indicative of whether a lateral writing position offset was used while writing.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. A first codeword is generated comprising first redundancy, and first position information of the head relative to a first track is saved while writing the first codeword to the first track. A second codeword is generated comprising second redundancy, and second position information of the head relative to a second track is saved while writing the second codeword to the second track. Extended redundancy is generated for the first codeword based on the first and second position information, and the first codeword is recovered from the first track based on the extended redundancy generated for the first codeword.

Abstract: The invention generally relates to a hard disk drive with a disk, a read/write head, a z-axis actuator, and a controller. A surface of the disk and/or the head can be bare and thus devoid of any overcoat or lubricant layer, or alternatively the disk surface can have one or more layers with a combined thickness of less than 4 nanometers and the head can have a layer with a thickness of less than 2 nanometers. The hard disk drive can be enclosed, and its enclosed space can be a low pressure environment such as a near-zero or a zero pressure environment.

Abstract: A storage device includes a multi-reader transducer head with a first reader and a second reader having an effective cross-track separation equal to a multiple of a defined track-pitch of a storage medium of the storage device. The effective cross-track separation may permit for a simultaneous data read of two non-adjacent data tracks.