According to one embodiment, a magnetic disk device includes a disk having a first region in which a plurality of tracks is written and a second region that is positioned with a gap in a first direction of the radial direction of the first region, and in which a plurality of tracks is overwritten in the first direction, a head, and a controller that offsets part of a plurality of tracks which is overwritten in the second region in a second direction opposite the first direction to perform rewriting.

According to one embodiment, a magnetic disk device includes: a disk; a head including a main magnetic pole, a write shield that faces the main magnetic pole in a first direction and is separated from the main magnetic pole by a gap, a first assist element that is disposed in the gap and a second assist element that is disposed in the gap and is positioned relative to the first assist element in a second direction intersecting the first direction; and a controller configured to: cause a first assist energy from the first assist element to be applied to the disk and affect a coercive force of the disk; and cause a second assist energy from the second assist element to be applied to the disk and affect a coercive force of the disk, wherein the first assist energy is different from the second assist energy.

Methods and systems for managing data storage strategies for continuous video segment recordings on a video recording device are disclosed. The data storage strategies include the detection of various trigger events and ending events detected from the video recordings or measurements detected from sensor devices that are included in the video recording device.

An information processing apparatus, for recording data in a magnetic storage medium by a shingled magnetic recording, and a method of controlling this, when a rewrite of data stored in the magnetic storage medium is instructed, copy data of a zone in which rewrite target data is stored other than the rewrite target data into a vacant zone of the magnetic storage medium; store, to the vacant zone into which the data is copied, the rewrite target data, delete by overwriting an entirety of the zone in which the rewrite target data is stored with predetermined data, and register the overwritten zone as an unused area.

Systems and methods for improving read failure tolerance during read-modify-write operations of data storage systems accommodating a host that uses a logical sector of a size smaller than the physical sector size of the data storage system. In one embodiment, the data storage system can perform sector indirection in response to a read error during a read-modify-write command.

A magnetic disk apparatus of one of the embodiments stores read position dependency information on read signal quality of a data region at a first track and measures the read signal quality at a predetermined radial position in a second data region of a second track different from the first track. A positioning error of the second data region is determined based on the read position dependency information and the read signal quality at the predetermined radial position. Data is recorded in a recording target data region in a shingled recording so as to prevent data written in the second data region from being overwritten by data in a recording target data region adjacent to the second data region by using the determined positioning error.

According to one embodiment, a magnetic disk device includes: a disk; a head including a main magnetic pole, a write shield that faces the main magnetic pole in a first direction and is separated from the main magnetic pole by a gap, a first assist element that is disposed in the gap and a second assist element that is disposed in the gap and is positioned relative to the first assist element in a second direction intersecting the first direction; and a controller configured to: cause a first assist energy from the first assist element to be applied to the disk and affect a coercive force of the disk; and cause a second assist energy from the second assist element to be applied to the disk and affect a coercive force of the disk, wherein the first assist energy is different from the second assist energy.

A recording device includes: a recording unit that records plural objects including data and metadata related to the data on a portable recording medium, and executes a process of recording first set data, which is a set of the metadata included in the object, at every predetermined timing after recording at least one of the objects, wherein each piece of the first set data is a set of the metadata included in the object recorded after recording of immediately preceding recorded first set data.

A method for indexing a tape for unmounting from a tape drive is discussed. The method can determine that an update has been made to the tape since it was last mounted. The method can identify a tape head position with respect to the tape, the tape including a data partition and an index partition. The method can identify first position and a second position on the tape. The method can determine first distance, a length of tape between first position and tape head position. The method can determine second distance, a length of tape between first position and second position. The method can determine that first distance is less than second distance. The method can reposition the tape to a primary section and write the metadata index. The method can reposition tape to the second position write a data index beginning at the second position of the data partition.

A method includes writing first data on a first track of a data storage surface, and storing information for the first data in a memory other than the data storage surface. The method also includes performing a write operation on a second track of the data storage surface after the data is written on the first track. The second track is adjacent to the first track. The method further includes identifying potentially-overwritten sectors of the first track as a result of the performance of the write operation on the second track, and performing a first read operation on the identified potentially-overwritten sectors of the first track after completion of the write operation on the second track. Second data associated with the identified potentially-overwritten sectors is then stored in a solid-state memory, and mirrored to media.