According to one embodiment, a disk device includes a magnetic disk, a ramp, a head stack assembly (HSA), and a housing. The ramp is rotatable between a first position covering a portion of the magnetic disk and a second position separated from the magnetic disk. The HSA is rotatable to a load position, an unload position, and a retracted position at which the HSA is separated from the magnetic disk. The ramp includes a first support portion that supports the lift tab when moving between the load position and the unload position at the first position, and a second support portion that supports the lift tab when moving between the unload position and the retracted position at the second position. The housing includes a first abutment portion that abuts the ramp at the first position to restrict rotation of the ramp.

According to one embodiment, during a first write period, if determining that error correction of first user data does not exceed a limit, a determination unit causes a write processing unit to continue write processing and causes a management unit to execute second management. If determining that the error correction exceeds the limit, the determination unit causes the write processing unit to continue the write processing and causes the management unit to execute third management. During the first write period or after the first write period, the determination unit causes the management unit to execute processing of saving data belonging to a third group to a nonvolatile recording medium.

According to one embodiment, a magnetic disk device of an embodiment includes a rotary shaft, a shroud, and a damper. The rotary shaft rotates the plurality of disks. The shroud surrounds at least a part of the disk along the outer edge of the disk with a space from the outer edge of the disk. The damper is provided on a downstream side of the shroud with respect to a flow between the disks induced by rotation of the disks, and the damper has a portion intersecting with the flow and a portion along the flow.

According to one embodiment, a magnetic disk device including a controller. The controller writes adjustment patterns, reads the written adjustment patterns, and detects the number of signal components of the sync mark included in the read signal, selects a frequency of an adjustment pattern from which the detected number larger than or equal to a threshold value is obtained, among the read adjustment patterns, as a write frequency of each of magnetic heads, writes spiral patterns including the sync mark in each predetermined cycle with the same frequency as each of the selected write frequencies, and writes a servo pattern, while tracking each of the written spiral patterns.

Beginning of wrap (BOW) data set reading and writing for tape drives is provided. In response to reaching an end of wrap (EOW) while writing to tape, a tape directory (TD) is updated to include first data set information for a first data set written at the EOW of a first wrap. A second data set is written using normal write procedure from a BOW of a second wrap, the second wrap following the first wrap. The first data set information is overwritten with second data set information for the second data set written at BOW. When reading a BOW data set from tape, data set information is read from a TD. Based on determining whether the data set information corresponds to a BOW data set, a target Data Set ID and a target Tape Write Pass are set for reading the BOW data set.

An apparatus includes a linear actuator assembly with a rail, a carriage, and a piezoelectric actuator. The carriage is coupled to the rail such that the carriage is movable with respect to the rail, and the piezoelectric actuator is configured and arranged to cause the carriage to move linearly between ends of the rail.

According to an embodiment, in a magnetic disk device, a current detection circuit detects an amount of a first current that is generated by a drive circuit and drives a motor. In a seek operation, a controller acquires a commanded value based on a deviation amount of the amount of the first current detected by the current detection circuit from the commanded value. Then, the controller inputs the acquired commanded value to the drive circuit.

A voice coil motor (VCM) in a hard disk drive having a VCM resistance is driven based on a value of the back electromotive force (BEMF) of the VCM reconstructed from a voltage drop indicative of the intensity of a current flowing towards the VCM detected by an amperometry resistance. The BEMF of the VCM is reconstructed as a function of the voltage drop via a first gain value, determined as the ratio of the VCM resistance to the amperometry resistance. A calibrated gain value, indicative of the ratio of the actual VCM resistance to the amperometry resistance is produced by applying a correction factor to the first gain value. The VCM is driven continuously based on a value of the BEMF of the VCM reconstructed by applying to the voltage drop the calibrated gain value.

According to one embodiment, an evaluation method is provided. The evaluation method includes obtaining first accuracy information. The first accuracy information relates to positioning accuracy of the head when a head is caused to seek to a first radial position in a disk medium. The evaluation method includes determining whether the first radial position is good or poor depending on the first accuracy information.

Disclosed are sealed enclosure HAMR hard drives, and methods for use therewith, that reduce the rate of depletion of gaseous Oxygen within the sealed HAMR drive enclosure, thereby leaving an amount of Oxygen available for mitigation of the effects of carbonaceous residue formation, thus extending the useful life of the HAMR drive. In sealed enclosure HAMR hard drives that include a component having a NdFeB alloy magnet, the sealed enclosure is filled with a gas mixture that includes primarily Helium along with a sufficient amount of Oxygen to mitigate carbonaceous residue formation during the lifetime of the drive and a sufficient amount of Nitrogen to reduce the rate of Oxygen depletion due to oxidation of the NdFeB magnet.