Abstract: According to one embodiment, physical position information on errors on a recording medium is acquired, physical position relationship between the errors on the recording medium is calculated based on the position information, and a failure mode related to the errors is determined based on the position relationship.

Abstract: Systems and methods for compensating for hysteresis in a disc drive are described. In one embodiment, a method may use an inverse hysteresis model to linearize effects of hysteresis of a microactuator in the disc drive. The hysteresis model may be a Coleman-Hodgdon hysteresis model. The hysteresis of the microactuator may be characterized, and the inverse hysteresis model may be based at least in part on the characterization. The inverse hysteresis model may be used to implement a digital filter. The digital filter may be employed in series with the microactuator to linearize the effects of hysteresis.

Abstract: In one general embodiment, a method includes calculating a differential position value based on readback signals from at least two servo readers of a magnetic head reading servo tracks of a magnetic recording tape. The differential position value is compared to a previously-calculated differential position value. An action is performed in response to determining that the difference between the differential position value and the previously-calculated differential position value is in a predefined range. In another general embodiment, an apparatus includes a magnetic head having at least two servo readers, and a controller in communication with the servo readers. The controller is configured to detect a sudden change in a width of a magnetic recording tape based on a differential position value derived from relatively more current servo readback data and a second differential position value derived from relatively older servo readback data.

Abstract: Systems and methods for compensating for magnetoresistive (MR) jog offset direct current (DC) drift in a disc drive are described. In one embodiment, a method may include determining an occurrence of NOS, for example, by monitoring disc slip, to determine when the method should proceed. An MR jog offset DC drift amount is determined for each head of the disc drive. One of several approaches may be employed for determining the MR jog offset DC drift amount. By determining an MR jog offset DC drift amount for each head, a compensation profile is determined for the drive. The determined compensation profile may then be used during operation of the disc drive to compensate for the DC drift. One of several approaches may be employed for compensating based on the compensation profile.

Abstract: The magnetic tape device includes a magnetic tape; and a servo head, in which the servo head is a TMR head, the magnetic tape includes a servo pattern in the magnetic layer, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and a ratio (Sdc/Sac) of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster thereof in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

Abstract: Some embodiments are directed to tape drive systems that oscillate the relative transverse position of the tape and magnetic head during seek operations (for example, by moving the head in the transverse direction). Some embodiments are directed to tape drive systems that select relative transverse position of the tape and magnetic head to counter uneven wear (for example, observed uneven wear, uneven wear predicted based on historical tape and drive usage data).

Abstract: A control device is provided which can perform a retraction operation of a head included in a disk storage device with lower power consumption. The control device of the disk storage device includes a control unit that controls a motor and retracts the head from over a disk to a ramp mechanism when power supply is shut down, an acquisition unit that acquires information related to a moving distance of the head that retracts to the ramp mechanism, and a calculation unit that calculates the moving distance of the head based on the information acquired by the acquisition unit. The control unit switches an operation of the motor from a first retract operation to a second retract operation when determining that the head reaches a first position after passing through an inclined surface of the ramp mechanism based on the moving distance calculated by the calculation unit.

Abstract: A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. Moreover, the program instructions readable and/or executable by a controller to cause the controller to perform a method which includes: determining, by the controller, whether a difference between information and corresponding design values is in a range; and computing, by the controller and using the information, data describing a lateral writing position to use during writing such that shingled track edges are aligned according to a format in response to determining that the difference between the information and corresponding design values is not in the range. The information corresponds to how an array of writers write and/or are expected to write to a magnetic medium during shingled recording.

Abstract: An apparatus-implemented method according to one embodiment includes passing a magnetic recording tape over a plurality of modules having write transducers, and causing the write transducers to write predefined patterns of magnetic bars on the magnetic recording tape. Associated pairs of the write transducers are aligned along an intended direction of tape travel thereacross. Planes of deposition of write gaps of the write transducers in each associated pair are oriented at an angle of greater than 4 degrees relative to each other. A timing of writing of each write transducer is controlled such that resulting patterns of magnetic bars written by each associated pair are offset from one another in the intended direction of tape travel.

Abstract: According to one embodiment, a hard disk drive includes a disk including a plurality of data areas, and a plurality of servo areas between the plurality of data areas, an arm holding a write head and a read arm, and a positioning module which positions the read head or the write head by rotating the arm, wherein the positioning module positioning the write head by positioning the read head, and adjusting a position of the read head or the write head, based on an output of the read head located in a data area between two servo areas adjacent in a peripheral direction, of the plurality of servo areas.

Abstract: A tape drive system with a transducer (for example, a magnetic head arrays/separation shield) located in a recess of a transducer housing (for example, supporting rails, a U-shaped carbon tape guide). During seek operations and/or data access operations (that is, read/write operations), the transducer and the transducer housing are moved, in the transverse direction relative to the direction of elongation of the tape, independently of each other. The motion of the transducer housing (for example, back and forth oscillatory movement in the transverse direction) is controlled to even out wear across the tape-facing surface of the transducer housing. Some embodiments accomplish this by using separate motors to transversely move the transducer and the transducer housing.

Abstract: Systems and methods are disclosed for head delay calibration and tracking multi-sensor magnetic recording (MSMR) systems. In certain embodiments, an apparatus may comprise a first reader and a second reader configured to simultaneously read from a single track of a data storage medium, the first reader offset from the second reader such that the first reader and the second reader detect a same signal pattern offset in time. The apparatus may further comprise a circuit configured to determine a relative offset between the first reader and the second reader, including setting a fixed delay for a first signal from the first reader, setting a second delay for a second signal from the second reader, and adjusting the second delay to align the second signal to the first signal using a timing loop, with the first signal used as a reference signal.

Abstract: According to one embodiment, a magnetic disk drive records and reproduces referential data and measures a referential characteristic value in a state in which supply of a STO voltage is stopped, executes control of reducing a temperature set value of a heater at a recording operation, based on the referential characteristic value, records and reproduces corrected data and measuring a corrected characteristic value in a state of supplying the STO voltage with a polarity opposite to a polarity at a general operation, while varying the temperature set value at a recording operation, compares the referential characteristic value with the corrected characteristic value and obtaining a difference, and corrects the temperature set value based on the difference.

Abstract: According to one embodiment, a magnetic disk apparatus includes a magnetic head, a voice coil motor, a driving circuit, and a VCM resistance estimation unit. The magnetic head accesses a magnetic disk. The voice coil motor drives the magnetic head over the magnetic disk. The driving circuit applies a VCM current to the voice coil motor. The VCM resistance estimation unit estimates a VCM resistance in the voice coil motor based on the saturated VCM current and a velocity of the magnetic head.

Abstract: A method, apparatus, and system are provided for implementing track following using signal asymmetry metrics monitored during read back in hard disk drives (HDDs). Signal asymmetry metrics monitored during read back are used together with a position error signal (PES) to correct and guide the position of a read sensor with respect to a written track in the HDD.

Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which the servo head is a TMR head, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder, a binding agent, and fatty acid ester on the non-magnetic support, the magnetic layer includes a servo pattern, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between a spacing measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 9.0 nm.

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: 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: 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 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°.