A storage device includes a controller that selects an offset when preparing to write data to a target data track. The offset defines a position for a write head relative to a center of the target track and is selected based on a radial position of a write head at the target data track.

According to one embodiment, a magnetic disk device including a disk, a head which writes data to the disk and reads data from the disk, and a controller which sets a first DOL for a first sector group and a second DOL for a second sector group to different values, the first sector group including one or more first sectors and a first parity sector, the first sectors which allow an error correction process to be performed for each track based on the first parity sector, and are continuously arranged in a circumferential direction of the disk from the first parity sector, the second sector group including one or more second sectors which allow no error correction process to be performed for each track, and are continuously arranged in the circumferential direction.

A storage device includes a storage medium having a first set of non-adjacent data tracks having a number of super parity sectors and a second set of non-adjacent data tracks interlaced with the first set of non-adjacent data tracks. The number of super parity sectors on a data track of the first set of non-adjacent data tracks is selected based on a distance between the data track and an inner diameter of the storage medium.

A storage device includes a storage controller configured to write a band of data tracks using a first recording method until criterion is met. The first method may be a conventional recording method. After the criterion is met, the storage controller is configured to write data to the band using a second recording method. The second recording method may be an enhanced capacity recording method such as interlaced magnetic recording (IMR) or shingled magnetic recording (SMR).

Methods, apparatuses and systems for detecting defective sectors on a recording medium, the method including calculating a servo gain for each servo sector of a track of a recording medium of a storage device; determining whether the servo gain of each servo sector exceeds a threshold value; and upon determining that the servo gain of a servo sector exceeds the threshold value, determining data sectors included in the servo sector to be defective sectors.

According to one embodiment, a magnetic disk device including a disk, a head which writes data to the disk and reads data from the disk, and a controller which sets a first DOL for a first sector group and a second DOL for a second sector group to different values, the first sector group including one or more first sectors and a first parity sector, the first sectors which allow an error correction process to be performed for each track based on the first parity sector, and are continuously arranged in a circumferential direction of the disk from the first parity sector, the second sector group including one or more second sectors which allow no error correction process to be performed for each track, and are continuously arranged in the circumferential direction.

According to one embodiment, in a disk device, a disk medium has a recording surface configured to face the head, the disk medium being medium where multiple tracks defined on the recording surface, each of the multiple tracks including multiple sectors. A controller is configured to perform error correction for each of the sectors on a per track basis. The controller is configured to predict, while writing data to a first track of the multiple tracks by a head, that the number of error sectors of a second track adjacent to the first track reaches a correction limit number of sectors, according to a track margin identified by first management information and an off-track amount of the first track. The controller is configured to update the first management information according to a bit error rate reference value and a bit error rate of information read from a track.

According to one embodiment, a magnetic disk device including a disk, a head which writes data to the disk and reads data from the disk, and a controller which sets a first DOL for a first sector group and a second DOL for a second sector group to different values, the first sector group including one or more first sectors and a first parity sector, the first sectors which allow an error correction process to be performed for each track based on the first parity sector, and are continuously arranged in a circumferential direction of the disk from the first parity sector, the second sector group including one or more second sectors which allow no error correction process to be performed for each track, and are continuously arranged in the circumferential direction.