According to one embodiment, a magnetic disk device including a disk including a user data region having a first region to which data is written by shingled recording and a cache region to which data is written by normal recording and is temporarily written before writing the data in the user data region, a head, and a controller including a first saving threshold value of the number of times of writing that data is written in the radial direction of the first region for saving a track located at an end portion of the first region in the radial direction into the cache region, and a refresh threshold value of the number of times of the writing for rewriting a plurality of tracks shingled recorded in the first region.

According to one embodiment, a magnetic disk device includes a first disk, the second disk, and a first head which writes and reads to the first disk, a second head which writes and reads to the second disk, and a controller which calculates an estimated position at which the second head is estimated to be disposed on the second disk based on first relative position information related to a relative position in a radial direction between the first head and the second head when the first head is switched to the second head.

A method includes determining an error after attempting to read, via a first read transducer and a second read transducer, a data sector in a first data track. The method further includes calculating a weight ratio associated with the data sector and determining a read offset direction of the data sector based, at least in part, on the calculated weight ratio.

According to one embodiment, a magnetic disk device includes a disk including a zone servo boundary area including a first area of a first servo frequency, a second area of a second servo frequency, and a third area of the first servo frequency, in a servo area, a head, and a controller demodulating first servo data of the first area to derive a position of the head and demodulating first corrected data of the third area to correct the position of the head. The first area, the second area, and the third area are aligned in order in a traveling direction. The first area and the second area are adjacent to each other in a circumferential direction of the disk. The second area and the third area are adjacent to each other in the circumferential direction.

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.

The present disclosure is generally related to a tape drive comprising a tape head and a controller. The tape head comprises a first assembly and a second assembly disposed adjacent to the first assembly, each assembly comprising a write module comprising a plurality of write heads and a read module comprising a plurality of read heads. When a tape moves in a first direction, the controller is configured to control the tape head to write data to the tape using the write module of the first module and read data from the tape using the read module of the first assembly. When the tape moves in a second direction opposite the first direction, the controller is configured to control the tape head to write data to the tape using the write module of the second module and read data from the tape using the read module of the second assembly.

A servo writer includes a running unit that sends a tape-like magnetic recording medium out from a cartridge, winds up the sent out magnetic recording medium, and runs the magnetic recording medium; an erasing unit that erases a first servo pattern formed in the magnetic recording medium that runs; a head that writes a servo signal in the running magnetic recording medium from which the first servo pattern is erased and forms a second servo pattern; and a control unit that controls the head so that the servo signal is written in at least one period of an accelerated running period and a decelerated running period of the magnetic recording medium, and forms the second servo pattern that does not satisfy a standard in the magnetic recording medium.

According to one embodiment, when adjusting a position of a magnetic head by a microactuator, in a case where a difference of an absolute value of a first voltage value obtained by correcting a voltage value applied to the microactuator based on hysteresis and an absolute value of a second voltage value obtained by not correcting the voltage value applied to the microactuator based on the hysteresis is positive, a control unit applies a third voltage value obtained based on the second voltage value to the microactuator, and adjusts shortage of the adjustment executed by the microactuator by controlling at least one of a voice coil motor and/or a microactuator other than a microactuator applying a third voltage value.

According to an embodiment, a magnetic disk device includes a magnetic disk, a magnetic head that accesses the magnetic disk, a motor that moves the magnetic head, a ramp, a motor driver, and a processor. When a voltage value of a power supply voltage falls below a first threshold, the motor driver starts a retract operation of retracting the magnetic head to the ramp by controlling a voltage applied to the motor. When the voltage value of the power supply voltage falls below a second threshold larger than the first threshold, the processor transmits an instruction related to applying a brake to the movement of the magnetic head to the motor driver.

According to an embodiment, a magnetic disk device includes a magnetic disk, a magnetic head that accesses the magnetic disk, a motor that moves the magnetic head, a ramp, a motor driver, and a processor. When a voltage value of a power supply voltage falls below a first threshold, the motor driver starts a retract operation of retracting the magnetic head to the ramp by controlling a voltage applied to the motor. When the voltage value of the power supply voltage falls below a second threshold larger than the first threshold, the processor transmits an instruction related to applying a brake to the movement of the magnetic head to the motor driver.