Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Western Digital Technologies, Inc.

Takehiko Hamaguchi

Hisashi Takano

Yasutaka Nishida

Futoshi Tomiyama

Hideki Sawaguchi

Hiroshi Ide

Hideki Zaitsu

Atsushi Nakamura

Yohji Maruyama

Kyo Akagi

Hideaki Maeda

Reijiro Tsuchiya

Toru Matsushita

Akira Sakagami

Keiichi Okada

Hirofumi Sukeda

Atsushi Saito

Masafumi Mochizuki

Yoshihiro Shiroishi

Hideki Saga

Mikio Suzuki

Takashi Kawabe

Hiroaki Nemoto

Masahiko Takahashi

Masuo Umemoto

Takayuki Ichihara

Kouichirou Wakabayashi

Kimio Nakamura

Fumiko Akagi

Naoto Ito

Kazuhisa Shishida

Masaomi Ikeda

Miki Hara

Mikio Tokuyama

Kenji Itoh

Kenya Ito

Katsuro Watanabe

Atsushi Kikugawa

Hiroki Mori

Yoshihisa Kamo

Hidekazu Kohira

Masayuki Kurita

Reiko Arai

Kiyoshi Matsumoto

Ikuya Tagawa

Yosuke Hamada

Yukiya Shimizu

Hitoshi Tamura

Kazuhiko Washizu

Kazuaki Usui

Hiroshi Umezaki

Tetsuo Yuki

Takashi Konishi

Norifumi Miyamoto

Mitsuru Hamaguchi

Kunihiko Mine

Liping Shen

The present disclosure generally relates to a tape drive comprising a tape wound around first and second tape reels and a tape head module configured to write data to and read data from the tape. The tape drive is configured to equalize the amount of time the tape spends stored in a first state and a second state when being stored long term, or when in a preservation phase, to minimize the effects of creep and tape dimensional stability. In the first state, a majority of the tape is wound around the first tape reel. In the second state, the majority of the tape is wound around the second tape reel. The tape drive is configured to move the tape between the first and second states: (1) upon being triggered by the timer, or (2) based on the tape head module being utilized to determine a position error signal.

Methods for improving track density in dual-reel removable tape devices and fixed tape devices

The present disclosure generally relates to increasing storage capacity for magnetic media dual-reel tape devices, and more specifically modifying the writing process to the magnetic media. Rather than having an unused acceleration zone, portions or even the entire acceleration zone on the tape can be used to store data. To achieve the acceleration to a predetermined speed, the tape is wound in the opposite direction from where the writing and/or reading will occur. The winding is of a sufficient distance to create sufficient distance along the tape for the acceleration to the predetermined speed to be completed by the time the writing and/or reading location is reached. Furthermore, when the acceleration zone is completely used for data, writing can occur from the beginning of the tape to the end of the tape rather than writing to/from the acceleration zone and then returning to a corresponding end of the tape.

Methods for increasing storage capacity and improving performance in dual-reel removable tape devices and fixed tape devices

The present disclosure generally relates to data storage devices, comprising: a magnetic tape; a tape head configured to write data to and read data from the magnetic tape; a first reel having a first interior surface; a second reel, wherein the first reel and the second reel are configured to wind and unwind the magnetic tape; one or more motors configured to actuate the first reel and the second reel; a first magnetic recording surface disposed on the first interior surface of the first reel; an actuating arm disposed between the first reel and the second reel; an actuator coupled to a distal end of the actuating arm; and a magnetic recording head disposed on the actuating arm. The magnetic recording head being situated a distance away from the actuator, wherein the actuating arm is configured to move about the actuator such that the magnetic recording head is able to contact the first magnetic recording surface to write data to and read data from the first magnetic recording surface.

Seek time to the beginning position of data on tape media

A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks, wherein each data track comprises a plurality of data segments. First data is written to data segments of a first data track, and second data is written to data segments of a second data track. After writing the second data, the first data is read at multiple off-track offsets of the first data track to measure an average off-track read capability (OTRC) of the first data track. A cross-track profile is generated for a first data segment of the first data track, and at least part of the cross-track profile is correlated with the measured average OTRC.

Data storage device defining track trajectory to reduce AC track squeeze

A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks, wherein each data track comprises a plurality of data segments. First data is written to a first data segment of a first data track, and second data is written to a second data segment of a second data track. After writing the second data, a quality metric is measured for at least two off-track offsets of the first data segment. A track pitch is estimated between the first data segment and the second data segment based on the quality metrics, and a track trajectory is generated for the second data segment based on the estimated track pitch. Third data is written to the second data segment based on the track trajectory.

A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks. A plurality of zones are defined for the disk, wherein each zone comprises a plurality of the data tracks. Position error signal (PES) repeatable runout (RRO) values are generated based on the servo data in a first zone, and data sector squeeze RRO values are generated based on data segments in the first zone. A first data track format for the first zone is generated based on the PES RRO values, and a second data track format is generated for the first zone based on the data sector squeeze RRO values.

Data storage device generating PES RRO and data sector squeeze RRO for a plurality of zones

According to one embodiment, a control method for a magnetic disk device includes writing data by varying a phase of the array period of the plurality of magnetic elements or a phase of the time period of the recording signal in one section of the track from a corresponding phase in another section of the track, reading a reproduction signal from the track, and determining a phase shift between the array period of the plurality of magnetic elements and the time period of the recording signal, based on a reproduction signal read from the one section and a reproduction signal read from the other section. In another embodiment, a magnetic disk includes a track in which magnetic elements are magnetically separated and arranged in an array period, and a phase of the array period in one section is different from a phase in another section of the track.

Control method for magnetic disk device, magnetic disk device, and magnetic disk

In a method of servo writing of a magnetic recording system and the magnetic recording system, the signal is recorded in a dummy area with a higher recording density than the burst signal. Also, the maximum bit length of the burst area is shortened as compared with the maximum bit length of the data area. A servo control method for perpendicular recording similar to that for longitudinal recording can be used to reduce the development cost. The anti-signal decay performance is also improved. Further, since the variations of the burst signal along the track width is suppressed, the positioning accuracy is improved. These effects combine to produce a reliable magnetic recording system of large capacity.

Method of servo writing for magnetic recording system, magnetic recording system

Embodiments in accordance with the present invention provide a degaussing device and a degaussing method capable of efficiently degaussing a magnetic disk, especially, a magnetic disk of the perpendicular magnetic recording system, without resorting to a magnetic field of a high intensity. Embodiments in accordance with the present invention provide a degaussing method of degaussing a magnetic disk not yet installed in a magnetic disk drive by applying an external magnetic field to the magnetic disk by a degaussing device. In accordance with one embodiment, the method includes disposing the magnetic disk in the degaussing device such that the direction of an external magnetic field is inclined at an angle to the axis of easy magnetization of the magnetic disk.

Magnetic disk degaussing device and degaussing method

A magnetic disk apparatus including: a disk holding data as magnetic information on a magnetic recording film; a head to perform writing and reading of the magnetic information; a rotary actuator to move the head in a radial direction of the disk; plural heat elements in the head to locally heat the disk; a write element in the head to apply a magnetic field to the disk; and means for selecting at least one heat element from the plural heat elements, wherein the means for selecting the heat element selects at least one heat element from the plural heat elements so as to bring a center line of an area heated by the heat element and a center line of the position of the magnetic field generated by the write element into approximate correspondence, in correspondence with a relative angle between the head and a direction of movement of the disk.

Magnetic disk apparatus having an adjustable mechanism to compensate write or heat element for off-tracking position with yaw angle

In a magnetic disk apparatus, mounting of plural heating elements to a magnetic head slider is permitted. Thermally assisted magnetic recording from inner to outer surface is permitted at a small amount of power consumption. In one embodiment, the magnetic disk apparatus has a magnetic disk on which magnetic information is recorded, a magnetic head slider having an air bearing surface for floating from the magnetic disk in proximity thereto, and a rotary actuator moving over the disk arcuately while supporting the magnetic head slider by a suspension. A recording element acting to record magnetic information on the magnetic disk, a playback element acting to play back the magnetic information recorded on the magnetic disk, and plural heating elements acting to locally heat the magnetic disk are carried on the magnetic head slider. A circuit for switching energization to the plural heating elements and according to information about the direction of a DC power supply VH, frequency contained in an AC power supply, or the like is formed.

Thermal assist head slider

Embodiments of the invention provide an inexpensive magnetic head tester employing component parts of a production HDD and capable of exercising functions very close to those of a production HDD. In one embodiment, a magnetic head tester employs the VCM actuator and the control circuit of a production HDD and has a lightweight, simple HGA fixing mechanism mounted on an actuator arm. The HGA fixing mechanism fixes an HGA to the actuator arm by a method using a very light holding spring mounted on the arm, a method of mechanically clamping an HGA by using air pressure, or a method of fixing an HGA to the arm by elastically deforming a rubber clamping member by air pressure. Servo control is achieved by the actuator of a production VCM. An end part of the VCM actuator is stopped by a stopping mechanism and is held by a holding spring to prevent the runaway of the VCM actuator. Servo control is performed by balancing the driving force of the VCM and the resilience of the spring.

Magnetic head tester and method of manufacturing magnetic disk drive

Embodiments of the invention prevent a decrease in magnetization or demagnetization from occurring to recording magnetization regardless of a direction in which a stray field is applied. In one embodiment, an apparatus for data storage system comprises a head having a magnetic field shield in the vicinity of a main pole, and a cover of the device, using a constituent material with a magnetic field shielding effect, across the cover, or at part thereof. When a stray field in a direction perpendicular to a recording medium is applied, the effect of the magnetic field is alleviated by the magnetic field shield installed in the vicinity of the main pole. In such a case, it need only be sufficient to form the magnetic field shield in a shape optimum for removing the stray field in the perpendicular direction only. When a stray field in a direction horizontal in relation to the recording medium is applied, the magnetic field acting on the recording medium is removed by the cover of the device comprising a magnetic component.

Perpendicular hard disk drive resistive against external magnetic field

The invention provides a servo pattern that is stable for long time, easily writable, and excellent in S/N. DC-signal area included in a burst area of a servo pattern comprises combination of positive and negative DC-signals, low-density dummy bit, or pattern having phases that are deviated each other so that the sum of magnetization of the burst area of the servo pattern is equalized to 0.

Alternative DC-burst servo pattern for perpendicular recording

In the present invention, by making the width of the write element larger than the track pitch and securing a write magnetic field strong enough to reverse the magnetization of the magnetic layer, and further by writing while shifting a write head comprising the write element, a magnetic disk drive, of which the track width is narrower than the write element width, and the storage capacity is large, is realized.

Magnetic disk drive

Growing community of inventors

Fuchu, Japan

Takehiko Hamaguchi