Abstract: In one embodiment, a method includes acquiring actual position information from encoding on a magnetic medium, calculating estimated position information of the magnetic medium using a media thickness value, comparing the estimated position information with the position information acquired from encoding, determining whether an error between the estimated position information and the acquired position information is within a specified range, in response to determining that the error is within the specified range, storing the media thickness value to a memory, and in response to determining that the error is outside the specified range, changing the media thickness value. In another embodiment, an apparatus includes a controller and logic integrated with and/or executable by the controller, the logic being configured to cause the controller to perform the foregoing method.

Abstract: In a disk apparatus, media include first and second surfaces having first and second servo patterns which are read at different timings by first and second heads. A controller controls the first head based on a first demodulated position obtained by demodulating the first servo pattern and a target position. The controller calculates a first estimated demodulated position from the demodulated position and a first demodulated velocity based on the first servo patterns, calculates a second estimated demodulated position from the first demodulated position and a second demodulated velocity based on the second servo patterns, and stops writing operation of the first head in accordance with one of the first and second estimated demodulated positions exceeding a threshold.

Abstract: A back electromotive force monitoring circuit has a speed detection voltage generator which biases a back electromotive force generated by a voice coil motor with a predetermined reference voltage to generate a speed detection voltage, and a calculator which generates a motor control signal in accordance with the speed detection voltage. The calculator includes a subtracter which subtracts the reference voltage from the speed detection voltage prior to generation of the motor control signal.

Abstract: An information processing system includes a first information processing apparatus coupled to a first magnetic-disk-device groups including first magnetic disk devices whose motors rotate, a second information processing apparatus coupled to a second magnetic-disk-device group including one or more second magnetic disk devices whose motors rotate and a plurality of third magnetic disk devices whose motors are in a stop state. A management apparatus which included in the system is configured to manage the first and second information processing apparatuses, wherein, when data is to be written, the management apparatus outputs a write request to any of the plurality of first magnetic disk devices and any of the one or more second magnetic disk devices, and when data is to be read, the management apparatus outputs a read request to any of the plurality of first magnetic disk devices.

Abstract: A product according to one embodiment includes a magnetic recording tape having at least one first servo track having timing information, and a supplemental servo track having at least one of: velocity encoding and longitudinal position encoding. An apparatus according to one embodiment includes a magnetic head and at least one module having an array of transducers. The apparatus is configured to read and/or write to magnetic recording media having at least one first servo track having timing information, and a supplemental servo track having at least one of: velocity encoding and longitudinal position encoding.

Abstract: A data storage device is disclosed comprising a disk comprising timing data, a spindle motor configured to rotate the disk, wherein the spindle motor comprises a plurality of windings, and a head actuated over the disk. A phase of a commutation controller is initialized based on the timing data on the disk, and a commutation sequence of the commutation controller is driven based on the timing data on the disk, wherein the commutation controller is configured to commutate the windings based on the commutation sequence. The phase of the commutation controller is re-initialized based on the timing data on the disk, thereby compensating for a cumulative phase error when driving the commutation sequence based on the timing data on the disk.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and a load/unload ramp. When seeking the head a seek length from a starting track to an ending track, control circuit is configured to adjust a seek profile when the seek length is greater than a first threshold and the ending track is within a second threshold of the load/unload ramp.

Abstract: A magnetic tape control apparatus includes a control device that executes a process including: detecting an occurrence of speed fluctuations of a running magnetic tape for each recorded area from which a synchronization error is detected, when the synchronization error of a bit signal of a track is detected with a time lag between any of tracks of the running magnetic tape partitioned in units of recording areas; and setting the recording area as an unavailable area in accordance with a state where the speed fluctuations in the recording area occur.

Abstract: A hard disk drive circuit includes first and second inter-track interference detection modules. The first inter-track interference detection module is configured to generate a first measured inter-track interference value based on a first read signal from a first read sensor positioned over a magnetic medium. The second inter-track interference detection module is configured to generate a second measured inter-track interference value based on a second read signal from a second read sensor positioned over the magnetic medium. A position error signal generation module is configured to generate a position error signal based on the first measured inter-track interference value and the second measured inter-track interference value. An arm control module is configured to control rotation of an arm in response to the position error signal. The first read sensor and the second read sensor are located at a distal end of the arm.

Abstract: Embodiments of the present invention are directed to the design and implementation of backward-compatible magnetic tape drives (102) that are read/write compatible with a current magnetic-tape format (1820) as well as one or more previous magnetic-tape formats (1802 and 1804). Embodiments of the present invention include read/write tape-head configurations (1902, 1904, 1906, 1908-1923, 1930, 1932, 1934, 2102) and corresponding magnetic-tape-drive-component features (518) that allow a magnetic-tape drive to read and write magnetic tapes formatted according to different formats.

Abstract: A motor drive device has a spindle motor driver adapted to receive electric power from a power supply line to drive a spindle motor; an isolation switch adapted to connect and disconnect an application terminal of a power supply voltage to and from the power supply line, and a current monitor adapted to monitor a first current flowing into the isolation switch.

Abstract: An apparatus for storing data includes a storage medium, a head assembly disposed in relation to the storage medium and operable to read and write data on the storage medium, a loop pulse estimation circuit operable to estimate a channel impulse response based on the data read by the head assembly, and a fly height detection circuit operable to detect a spacing between the head assembly and the storage medium based at least in part on the channel impulse response.

Abstract: A storage device has a device body and a read/write head for reading and writing data in a data track of a storage medium. An actuator system is mounted on the device body for effecting movement of the read/write head relative to the data track to align the head with the data track. The actuator system has a plurality of degrees of freedom, and a controller controls the actuator system to effect the movement. A body vibration sensor provided on the device body generates a signal indicative of vibration of the body. An actuator vibration sensor generates a signal indicative of vibration of the actuator system. The controller is adapted to process the signals from the sensors to derive a coupling signal indicative of vibration coupling between the degrees of freedom, and to control the actuator system dependent on the coupling signal and the signal from the body vibration sensor.

Abstract: An apparatus comprises a controller configured to detect a seek failure of a read/write head. The controller is additionally configured to perform a seek recovery operation in accordance with a recovery sequence in response to the seek failure; the recovery sequence comprising a plurality of recovery procedures. Further, the controller is configured to determine if the seek recovery operation is successful and determine which of the recovery procedures provided the success. And, the controller is configured to dynamically calculate the success rate of each recovery procedure, modify the recovery sequence based on the success of the seek recovery operation and based on the success rate of recovery procedures providing the success.

Abstract: An information recording device includes a recording medium with a plurality of data tracks and a controller that stores management information regarding data recorded in a group of adjacent data tracks, the recorded data including first data recorded in a first data track that is partially overwritten by second data subsequently recorded in a second data track that is adjacent to the first data track. The controller recovers management data of the recorded data based on whether or not a sector in the first data track that is adjacent to a sector in the second data track can be read by offset read processing when the sector in the second data track cannot be read by normal read processing.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, wherein the head comprises a write element radially offset from a read element by a writer/reader offset that varies relative to a radial location of the head over the disk. A first radial band (RB) of the data tracks is written from an outer diameter (OD) of the disk toward an inner diameter (ID) of the disk, and a first jog profile is calibrated for the first radial band that compensates for the writer/reader offset. A second RB is written from an ID to an OD, and a second jog profile is calibrated for the second RB that compensates for the writer/reader offset. The first RB is accessed using the first jog profile, and the second RB is accessed using the second jog profile.

Abstract: A method, apparatus, and system are provided for implementing noise based detection of spin-torque oscillator (STO) power on for microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). A low frequency noise generated by a spin-torque oscillator, such as noise in a frequency range between 10 kHz and 100 MHz, is detected. The detected STO noise is compared to a predefined threshold to identify STO power on operation.

Abstract: Technologies are described herein for writing servo reference patterns in a storage device implementing heat-assisted magnetic recording. A recording signal for the servo reference patterns is generated through a read/write channel to a read/write head of the storage device. The read/write head is moved across a recording surface of a disk in the storage device as the disk is rotated and an intermittent signal is applied to a write gate interposed between the read/write channel and the read/write head so that a maximum continuous writing time of the recording signal does not exceed a continuous write time limit of the storage device.

Abstract: A motor drive device has a motor driver adapted to receive a first power supply voltage to drive a motor; an internal regulator adapted to generate from an input voltage an internal power supply voltage; and a power supply switcher adapted to receive both the first power supply voltage and a second power supply voltage lower than the first power supply voltage to output, as the input voltage, the second power supply voltage when the second power supply voltage is normal and to output, as the input voltage, the first power supply voltage when the second power supply voltage is abnormal.

Abstract: A system including a tape library and a tape drive. The tape library identifies which tapes in the tape library include one or more migrated tapes. The tape drive provides access to each migrated tape of the one or more migrated tapes by an original application.