The present disclosure generally relates to using a data timestamp and/or a read counter to prevent data from being re-read and signal that the data has been accessed. The write assist element in the write head can be utilized to degrade the data or an allocated marker after the data has been read. The degradation functions as a read counter to indicate how many times the data has been read. Additionally and/or alternatively, a timestamp can be utilized. The timestamp is updated each time that the data has been accessed. In so doing, it is possible to determine whether data in a data storage device has been accessed.

According to one embodiment, a magnetic disk device includes a first disk including a first data sector, a second disk including a second data sector, a first head including a first read head, a second head including a second read head, a first controller that stops write operations of both the first head and the second head based on first data sector position error information obtained by reading and demodulating the first data sector by using the first read head, and a second controller that stops the write operations of both the first head and the second head based on second data sector position error information obtained by reading and demodulating the second data sector by using the second read head.

The present disclosure generally relates to a tape head and a tape drive including a tape head. The tape head comprises a first same gap verify (SGV) head assembly comprising a first media facing surface (MFS) and a plurality of first write transducer and first read transducer pairs, and a second SGV head assembly comprising a second MFS and a plurality of second write transducer and second read transducer pairs. During operation, when a tape or magnetic media moves in a first direction over the tape head, the tape contacts the second MFS and is spaced from the first MFS, and when the tape moves in a second direction opposite the first direction over the tape head, the tape contacts the first MFS and is spaced from the second MFS. As such, the tape contacts only one edge of either the first or second MFS during operation.

The present disclosure generally relates to a tape head and a tape drive including a tape head. The tape head comprises a first same gap verify (SGV) head assembly comprising a first media facing surface (MFS) and a plurality of first write transducer and first read transducer pairs, and a second SGV head assembly comprising a second MFS and a plurality of second write transducer and second read transducer pairs. During operation, when a tape or magnetic media moves in a first direction over the tape head, the tape contacts the second MFS and is spaced from the first MFS, and when the tape moves in a second direction opposite the first direction over the tape head, the tape contacts the first MFS and is spaced from the second MFS. As such, the tape contacts only one edge of either the first or second MFS during operation.

The disclosed embodiments generally relate to a data storage device for accessing a magnetic tape. The device includes write heads writing data tracks on the magnetic tape and control circuitry configured to: (1) use the heads to write a first set of data tracks on the magnetic tape; (2) measure a distortion of the first set of data tracks after the first set of data tracks have been written; and (3) use the heads to shingle write a second set of data tracks relative to the first set of data tracks based on the measured distortion. To compensate for the distortion, a priority servo is chosen based on whether the distortion is an expansion or contraction, and/or whether the shingle writing direction is inbound or outbound. The head bar is moved during shingle writing toward the servo track associated with the priority servo.

According to one embodiment, a magnetic disk device including a disk, a head that writes data with respect to the disk and reads data from the disk, and a controller that overwrites a second track on a first track in a radial direction of the disk, performs first alternative processing of recording a first user sector in a first region when writing of the first user sector available by a user in the first track is disabled, and performs second alternative processing different from the first alternative processing of recording a first parity sector in a second region when writing of the first parity sector acquired by an XOR operation in the first track is disabled.

Provided is a sputtering target to be used for forming a granular magnetic thin film in which FePt magnetic grains are isolated by an oxide and which constitutes a heat-assisted magnetic recording medium having enhanced uniaxial magnetic anisotropy, thermal stability, and SNR (signal-to-noise ratio).

The sputtering target for a heat-assisted magnetic recording medium contains an FePt alloy and a nonmagnetic material as main components, where the nonmagnetic material is an oxide having a melting point of 800° C. or higher and 1100° C. or lower.

Provided is a sputtering target to be used for forming a granular magnetic thin film in which FePt magnetic grains are isolated by an oxide and which constitutes a heat-assisted magnetic recording medium having enhanced uniaxial magnetic anisotropy, thermal stability, and SNR (signal-to-noise ratio).

The sputtering target for a heat-assisted magnetic recording medium contains an FePt alloy and a nonmagnetic material as main components, where the nonmagnetic material is an oxide having a melting point of 800° C. or higher and 1100° C. or lower.

Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surface; and one or more processing devices, the head comprising: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform spiral write operations of spiral patterns comprising a plurality of sync marks with the head on the corresponding disk surface, wherein the spiral write operations are performed at: a plurality of values of laser pre-bias current, write backoff, and/or start disk phase; detect pattern signal amplitudes of the spiral patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based on the pattern signal amplitudes of the spiral patterns.

Various circuits, systems, methods, and apparatus are disclosed to provide dynamic direct current (DC) level shifting for use with a summing component of a quad channel detector (QCD) of a media scanning system configured to detect carbon voids or other defects on the surface of a magnetic recording medium. In an example, a summing circuit receives separate input signals from four optical sensors of the scanning system and generates a summed output signal with an alternating current (AC) component representative of a defect and a direct current (DC) component representative of a total power of an optical transmitter of the scanning system. A DC level shifting circuit receives a fixed DC offset signal and the same four variable input signals. The DC level shifting circuit provides dynamic level shifting of the DC component of the summed output signal based on the fixed DC offset and the four input signals.