In a disk drive, when an off-track error occurs during a sequential disk access operation that spans multiple contiguous data tracks, efficient recovery is performed. In an embodiment, the disk access operation (e.g., reading from or writing to a disk) is attempted for all sectors of the sequential disk access operation. The disk access operation is then attempted again for sectors associated with any off-track errors that occurred during the disk access operation. In another embodiment, when an off-track error occurs during a sequential write operation in a shingled magnetic recording drive, the data originally targeted to be written to a first portion is written to a second portion of the data track that follows the first portion. Since no additional revolutions of the disk are needed for data associated with the sequential write operation to be written to the disk.

A method reduces the effect of accelerating/decelerating an aggressor actuator in a multi-actuator drive on a victim actuator in the drive. Measurements of fractional-wedge timing-offsets for an aggressor head are used to adjust the aggressor actuator commands that are inputted to a victim disturbance feedforward signal generator when a timing offset exists between the currently-used aggressor head and the aggressor head that was used to measure transfer functions for determining victim feedforward signals. When such a timing offset is equivalent to a specific fraction of the time period separating servo wedges, values of the aggressor actuator commands that are inputted to the victim disturbance feedforward signal generator may be modified based on the specific fraction. Feedforward signals may be modified when a timing offset exists between and the current timing of the currently-used victim head and an original timing of the currently-used victim head.

According to one embodiment, a magnetic disk device which includes two or more independently drivable actuator blocks and performs seek control with a low jerk in which a jerk that is a derivative of acceleration is limited, wherein in a state where a first actuator block is not accessing a data sector of a disk, a second actuator block that is not the first actuator block accesses the data sector of the disk by seek control with a high Jerk.

A magnetic disk device includes a magnetic disk including a track having a plurality of sectors, a motor configured to rotate the magnetic disk, a magnetic head, and a controller. The controller is configured to perform a first read operation of reading target sectors among the sectors of the track, with the magnetic head during a first revolution of the magnetic disk, detect an off-track state of the magnetic head during the first revolution of the magnetic disk, perform a first error correction with respect to data read from the target sectors during the first read operation, and perform a second read operation of selectively reading a part of the target sectors for which the off-track state has been detected or the first error correction is unsuccessful, with the magnetic head during a second revolution of the magnetic disk.

An apparatus, according to one approach, includes an inner array of data transducers on a module, the data transducers of the inner array being aligned along a common axis that extends between distal ends of the module. Two outer arrays of data transducers are positioned on the module to sandwich the inner array therebetween. Inner servo readers are positioned between the inner array and the outer arrays. Outer servo readers are positioned toward outer ends of the outer arrays. A method, according to one approach, includes passing a magnetic recording tape having a plurality of data bands over a module as described above. Data on two of the data bands is simultaneously transduced (read and/or written) using the data transducers of the inner and outer arrays. Thus, the bandwidth of the data operation can be increased, e.g., effectively doubled.

According to one embodiment, a magnetic disk device including a disk, a head, and a controller configured to, when writing a first servo sector, a second servo sector, and a third servo sector in the order described according to a second route varying in a radial direction of the disk with respect to a first route, adjust first timing used to write the second servo sector next to the first servo sector, and adjust second timing used to write the third servo sector next to the second servo sector.

A servo writer includes a writing head that writes a servo signal on a long magnetic tape that is traveling and at least two first guide rollers that guide the travel of the magnetic tape, in which the at least two first guide rollers on which a spiral groove is provided have a circumferential surface that has contact with the traveling magnetic tape, tensile forces act on the magnetic tape from the at least two first guide rollers in a width direction of the traveling magnetic tape, and the tensile forces that act on the magnetic tape from the at least two first guide rollers cancel each other.

A piezoelectric thin film-stacked body is provided. A piezoelectric thin film-stacked body has a first electrode layer, a first oxide layer stacked on the first electrode layer, a second oxide layer stacked on the first oxide layer, and a piezoelectric thin film stacked on the second oxide layer, the electrical resistivity of the first oxide layer is higher than the electrical resistivity of the second oxide layer, the first oxide layer includes K, Na, and Nb, and the piezoelectric thin film includes (K,Na)NbO.sub.3.

Embodiments of the present disclosure generally relate to tape drives used for magnetic recording on tapes, and more specifically to tape heads including servo and data head structures. A tape head includes a plurality of servo head structures and one or more piezoelectric devices. The one or more piezoelectric devices are utilized to control the spacing and dimensions between the plurality of servo head and data head structures. The one or more piezoelectric devices further allow the tape head to receive active feedback from the tape drive, allowing the one or more piezoelectric devices to correct any errors during operation.

In a disk drive, when an off-track error occurs during a sequential disk access operation that spans multiple contiguous data tracks, efficient recovery is performed. In an embodiment, the disk access operation (e.g., reading from or writing to a disk) is attempted for all sectors of the sequential disk access operation. The disk access operation is then attempted again for sectors associated with any off-track errors that occurred during the disk access operation. In another embodiment, when an off-track error occurs during a sequential write operation in a shingled magnetic recording drive, the data originally targeted to be written to a first portion is written to a second portion of the data track that follows the first portion. Since no additional revolutions of the disk are needed for data associated with the sequential write operation to be written to the disk.