Abstract: Managing a file on a tape. In response to a request to write a first file to a tape, whether a second file including data identical to the first file already exists on the tape is detected. If the second file exists, a first index of the second file is updated. After completing the write of the first file, metadata, including data starting position and size of the first file, is added to the first index. In response to a request to read the first or second files, the metadata of the first and second indexes are read. Based on the metadata, which of the first or second files can be accessed faster from a current head position is determined. The first file or the second file that can be accessed faster is then read from the tape.

Abstract: Various embodiments provide the position error signal (PES) that is generated by the data read channel that uses internal signals such as analog-to-digital signals, recovered data bits and signals or other internal signals to determine read head off-track metrics. Several different metrics can be utilized including a normalized norm metric, a normalized cross correlation metric, and a cross correlation with detected data metric. These metrics can be utilized to determine off-track shift of one or more read heads such that the read head position can be corrected.

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: A Data Storage Device (DSD) includes at least one disk surface and a plurality of actuators for accessing data stored on the at least one disk surface. A workload is determined for each actuator of the plurality of actuators, and a logical to physical mapping is modified based on at least one workload. The logical to physical mapping associates logical addresses of data with physical locations for storing the data on the at least one disk surface.

Abstract: A reference spiral is written on a recording surface of a hard disk drive. By launching writing of fine guide spirals from a launch point that is disposed on a pre-existing coarse guide spiral, writing of the fine guide spiral can be launched in response to a write head crossing the pre-existing coarse guide spiral, rather than in response to a precisely timed event. To enable launch points being disposed on pre-existing coarse guide spirals, launch points are not all located at the same radial position on the recording surface.

Abstract: A slider of a magnetic recording head comprises a plurality of electrical bond pads coupled to bias sources and a ground pad. Each of a plurality of electrical components of the slider is coupled one or more of the electrical bond pads, wherein at least one of the electrical bond pads is a shared electrical bond pad coupled to at least a first electrical component and a second electrical component. A switching transistor is coupled to the first and second components and the ground pad. The switching transistor is arranged to control powering of the second component in response to biasing of the first component.

Abstract: According to one embodiment, a magnetic disk drive in the present embodiment includes a disk including tracks, each including servo sectors, a head, and a controller configured to acquire first correction data for repeatable runout occurring in a first direction, and second correction data different from the first correction data, to write the first correction data within a first permitted range in the first direction, to write the second correction data within a write permitted range including the first permitted range and a second permitted range in a second direction opposite to the first direction, to read at least one of the first correction data and the second correction data, and to correctly place the head.

Abstract: A tape apparatus includes a tape drive and a processor. The tape drive is configured to perform data reading and data writing on a magnetic tape in which a plurality of tracks are formed. The processor is configured to control the tape drive to perform data reading and data writing on the plurality of tracks in a first segment among a plurality of segments obtained by dividing the magnetic tape in a running direction. The processor is configured to reserve a first track of the plurality of tracks as a copy target upon determining that an abnormality occurs in the first segment on the first track. The processor is configured to instruct the tape drive to copy data recorded in the first segment on the first track to a second segment on the first track at a predetermined timing. The second segment is adjacent to the first segment.

Abstract: A data storage device is disclosed comprising a first disk comprising first servo sectors A0-AN distributed around a circumference of the first disk, and a second disk comprising second servo sectors B0-BN distributed around a circumference of the second disk, wherein the second servo sectors B0-BN are offset circumferentially from the first servo sectors A0-AN. While the first and second disks are rotating second servo information is transmitted from a second servo channel to a first servo channel. One of the first servo sectors Ai is read to generate first servo information, and a first command value is generated based on the first servo information and the second servo information, wherein a first actuator is controlled based on the first command value.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. At least four different laser powers are applied to the laser and a fly height of the head over the disk is measured at each laser power. A lasing threshold power for the laser is detected based on the measured fly heights.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA). A FHA control signal is applied to the FHA, wherein the FHA control signal comprises a DC component and an AC component. A fly height metric is measured representing a fly height of the head over the disk for different levels of the DC component. A modulation amplitude of the fly height metric is detected, and a minimum in the modulation amplitude of the fly height metric is detected.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, and a sensor configured to generate a sensor signal representing at least one of a shock and a thermal popping affecting the data storage device. The sensor signal is first filtered based on a first frequency range corresponding to the shock to generate a shock signal, and second filtered based on a second frequency range corresponding to the thermal popping to generate a pop signal, wherein the second frequency range is different from the first frequency range. The shock signal and the pop signal are individually processed, for example, to log a disturbance event, to abort a write operation, or to generate a feed-forward servo compensation signal.

Abstract: In one embodiment, a computer-implemented method includes creating a spike in a servo channel from a predetermined start position to an end position, and storing servo data including at least a portion thereof generated during the spike. The spike has a predetermined amplitude. In another embodiment, a computer program product includes a computer readable storage medium having program instructions embodied therewith. The program instructions are executable by a controller to perform the foregoing method.

Abstract: The invention generally relates to a system for achieving reduced head-media spacing (HMS) in a hard disk drive (HDD) by providing active control over the positioning of a read/write head relative to a rotating magnetic data recording and reading surface of a disk. The system is configured to monitor and adjust positioning of the read/write head in real, or near-real time during disk rotation to maintain the HMS between a magnetic transducer of the read/write head and the disk surface within a defined range, generally between 1.0 nm and 10.0 nm, and, in some embodiments, approximately 4.3 nm. The system replaces the conventional an air bearing surface (ABS) design with a fully active suspension to maintain the head flying height within the desired range. The system further allows for each of the magnetic transducer and disk surface to be to be devoid of any overcoat or lubricant layers.

Abstract: A telemetry system with a plurality of controllers and telemetry systems, where the controllers are configured to obtain information from one or more sensors and transmit that information on one or more of the plurality of telemetry systems. The configuration of a controller may be changed so as to change which information is transmitted on a given telemetry system.

Abstract: A tape appliance that includes two outer write heads and an inner read head arranged along a magnetic tape path in WRW order, each write head tape bearing surface angled downward towards the inner read head. The heads are configured such that for a first direction of tape travel, the tape engages the tape bearing surface of a first write head followed by engaging the tape bearing surface of the read head and flies over the tape bearing surface of the other write head. For the reverse direction of tape travel, the tape engages the tape bearing surface of the other write head followed by engaging the tape bearing surface of the write head and flies over the tape bearing surface of the first write head.

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: The embodiments of the invention improve the traditional disk drives by eliminating the mechanical actuator assembly that moves the read-write head attached to the actuator assembly, and replacing it with multiple read-write heads mounted over one or more rotating platters. The number of the read-write heads is preferably sufficiently large so that the read-write heads cover all tracks on the one or more rotating platters. In one embodiment, a disk includes a rotatable platter, a central spindle to rotate the rotatable platter arounds an axis, an electric motor to drive the central spindle, and multiple read-write heads mounted over the rotatable platter. In one embodiment, the platter includes multiple tracks arranged in form of concentric circles, where each of the read-write heads performs read-write operations on one of the tracks, and each track is assigned at least one of the multiple read-write heads.

Abstract: Managing a file on a tape. In response to a request to write a first file to a tape, whether a second file including data identical to the first file already exists on the tape is detected. If the second file exists, a first index of the second file is updated. After completing the write of the first file, metadata, including data starting position and size of the first file, is added to the first index. In response to a request to read the first or second files, the metadata of the first and second indexes are read. Based on the metadata, which of the first or second files can be accessed faster from a current head position is determined. The first file or the second file that can be accessed faster is then read from the tape.

Abstract: An apparatus comprises circuitry configured to apply an AC signal having a frequency to one of a slider of a recording head and a magnetic recording medium. The applied AC signal causes an oscillation in an electrostatic force and clearance between the slider and the medium at the frequency of the AC signal. A thermal sensor is configured to generate a sensor signal at the AC signal frequency in response to sensing changes in temperature resulting from the oscillating clearance. A detector is coupled to the circuitry and the thermal sensor. The detector is configured to detect one or both of head-medium spacing changes and head-medium contact using a phase of a first harmonic or an amplitude of a second harmonic of the thermal sensor signal.