Hitachi Global Storage Technologies Netherlands B.v.

Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Western Digital Technologies, Inc.

Hgst Netherlands, B.v.

Hideki Zaitsu

Futoshi Tomiyama

Takehiko Hamaguchi

Hiroyasu Tanabe

Hisashi Takano

Masafumi Mochizuki

Hideaki Maeda

Reijiro Tsuchiya

Naoto Ito

Toru Matsushita

Hisao Okamoto

So Ogiwara

Weldon Mark Hanson

Yohji Maruyama

Niranjay Ravindran

Masukazu Igarashi

Hiroshi Ide

Kazue Kudo

Kyo Akagi

Alain Chahwan

Kei Yasuna

Takayuki Ichihara

Yoji Maruyama

Fumiko Akagi

Michiya Kazusawa

Ichiro Ohdake

Nelson Cheng

Sarbanoo Das

Akira Morinaga

Hideo Tanabe

Toshihisa Komai

Shuji Nishida

Yoshio Soyama

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: determine an initial track pitch based on a performance metric determined for the head; determine a track pitch adjustment based on a measure of servo pattern distortion associated with a region of the disk; and set a final track pitch for the region of the disk based on the track pitch adjustment and the initial track pitch.

Data storage device with track pitch determination for mitigating effects of servo pattern distortion

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, including consecutive data tracks N&#x2212;1 and N. A first write to data track N is performed using a first position error signal (PES) representing a position of the head relative to the data tracks. A track squeeze metric is generated for data track N&#x2212;1 based on at least the first PES of the first write. The track squeeze metric for data track N&#x2212;1 is accumulated during the first write, and the first write is aborted when the accumulated track squeeze metric for data track N&#x2212;1 exceeds a first threshold.

Data storage device aborting write operation based on accumulated track squeeze metric for adjacent data track

A method of storing data includes providing a write signal for a write head of a hard disk drive, generating a transition pulse signal derived from the write signal using a transition pulse generator, and generating a logic signal to drive a thermal source associated with the write head of the hard disk drive. The logic signal includes the logical summation of a cyclical base pulse signal and the transition pulse signal.

Self-controlled laser pulsing for thermally assisted recording

SMR disk drives are described that adjust track pitch or magnetic write width to compensate for external temperature effects. In one embodiment track pitch is increased when the media temperature increases. The temperature of magnetic media during write operations can be determined from the drives' temperature sensor. In other embodiments track pitch is adjusted based on the magnetic write width (MWW) which is determined from read-back testing of previously written data tracks. In an alternative embodiment, the width of the MWW is adjusted instead of the track pitch. The various factors that affect the MWW that can be used to increase or decrease the MWW, including write current characteristics and when available thermal-assistance parameters.

Dynamic track pitch control for shingled magnetic recording (SMR)

A head-slider configured to fly in proximity to a recording surface of a magnetic-recording disk. The head-slider includes a write element including a main pole configured to generate a magnetic-recording field from a pole tip of the main pole in a first localized portion of the magnetic-recording disk. The head-slider also includes a magnetic-recording assistance element configured to provide energy to a second localized portion of the magnetic-recording disk in order to increase reversibility of a magnetization in a first localized portion of the magnetic-recording disk. A width of the pole tip of the main pole on a leading-edge side is wider than a width of the pole tip of the main pole on a trailing-edge side.

Energy-assisted magnetic-recording head having a magnetic-recording assistance element disposed to lower magnetic-recording field for reversing magnetization in a magnetic-recording disk

To synchronize a write/read frequency with media with high precision even when a write head is positioned in a different zone in a magnetic recording/reproducing device equipped with patterned media formed with writing hit patterns and having a zoned format function, a write head is positioned on a recording track in the vicinity of a boundary between zones, and the write head is positioned in a different zone from the zone in which the read head is positioned, the preamble pattern in the zone in which the read head is positioned is reproduced, a difference between frequencies of the preamble patterns of the zones is compensated to determine a write frequency used for writing data into a desired track, and then start timing for writing is determined based on a synchronization pattern obtained at the position of the read head. Other systems and methods are presented as well.

Magnetic recording/reproducing using a patterned medium

Embodiments of the invention provide a magnetic read/write device capable of reading/writing data even when a reversal of the output polarity of the readback signal occurs. In one embodiment, a magnetic read/write device is provided which constantly checks the output polarity based on the polarity of the waveform of a signal obtained as a result of equalizing the waveform of a readback signal of gray code (indicating a cylinder number) in each servo sector by use of a matched filter (MF), or based on the waveform of a readback signal read from areas of a magnetic disk which store a special pattern for detecting the output polarity. When a polarity reversal has occurred, the magnetic read/write device assumes that a read error has occurred and performs processing so as not to perform any track seek or track following operation using decoded positional information. The magnetic read/write device then reverses the polarity of the output signal by use of a polarity reversing unit provided within or on the input side of a read/write channel, and resumes servo and read/write operations.

Magnetic read/write device preventing malfunction due to reversal in polarity

A magnetic recording device according to one embodiment includes a magnetic recording medium having a magnetic recording layer; a recording element positioned on a head slider; an assistance element for supplying assistance energy to an area on the recording layer to which a recording magnetic field generated by the recording element is applied, the assistance element being positioned on the head slider; and a controller for controlling a size of an assistance area from the assistance element in accordance with a position of the head slider in a radial direction of the magnetic recording medium. Additional systems and methods are also presented.

Magnetic recording device and magnetic recording method thereof

In one embodiment, a magnetic disk drive includes a magnetic disk, a head slider for flying above the spinning magnetic disk, a pattern analyzer for analyzing a data pattern of data to be recorded on the magnetic disk to determine a recording current reversal timing and a recording assistance area in accordance with the analysis so that the rear end of the determined recording assistance area is shifted forward if the determined recording current reversal timing is earlier than a criterion, or the rear end of the determined recording assistance area is shifted backward if the determined recording current reversal timing is later than the criterion, a recording assistance element on the slider for forming the determined recording assistance area on the magnetic disk, and a recording element for recording the data on the magnetic disk using the recording current in accordance with the determined recording current reversal timing.

Magnetic disk drive having assisted recording and methods of recording data thereto

Embodiments of the present invention achieve a high linear recording density and a high track recording density to thereby improve the areal recording density in a perpendicular magnetic recording apparatus having a magnetic head that includes a trailing shield and side shields around a main magnetic pole piece. According to one embodiment, in a magnetic recording apparatus, each of magnetic distances of various sorts is set so as to satisfy relationships of Lmag&#x3c;T-Gap and HUS&#x3c;S-Gap, where the magnetic shortest distance between the main magnetic pole piece and a trailing shield is defined as T-Gap; the magnetic shortest distance between the main magnetic pole piece and each of side shields disposed on both sides of the main magnetic pole piece is defined as S-Gap; a distance between a surface of the main magnetic pole piece and a lower surface of a magnetic recording layer constituting a recording medium is defined as Lmag; and a distance between the surface of the main magnetic pole piece and an upper surface of a soft magnetic underlayer of the recording medium is defined as HUS. Further, each of the magnetic distances of various sorts is set so as to satisfy a relationship of Lmag&#x3c;T-Gap&#x3c;HUS&#x3c;S-Gap.

Magnetic recording apparatus with correlated main magnetic pole-to-shields spacing and main magnetic pole-to-medium layers spacing

Embodiments of the invention provide a perpendicular magnetic head with a narrow track and excellent high frequency characteristics. In one embodiment, a recording magnetic head includes coil conductors and magnetic pole pieces putting the same therebetween, in which a main magnetic pole piece is formed into a planar structure and a magnetic film connected with the main magnetic pole piece in a magnetic coupling relation is curved in the direction of the film thickness. Further, a shield material disposed near the main magnetic pole piece is made of a material of higher resistance than that of the material for the read shield.

Perpendicular magnetic recording head for high frequency drive

An output of a magnetic head changes depending on the environmental temperature of a magnetic disk. In particular, under cold temperature conditions, an output of the head largely decreases mainly due to an increase in coercivity of a magnetic recording medium, which degrades an error rate. In one embodiment of the invention, sense-current optimization processing of a magnetic disk drive comprises the steps of: measuring the environmental temperature; and after a sense-current value which is set from the viewpoint of the reliability of the magnetic head is defined as an upper limit, finding out a sense current Is that can achieve the best error rate (BER) at the temperature. While changing a value of the sense current Is inside the magnetic disk drive, an error rate is measured. Then, a sense current Is_opt at which the best error rate properties are achieved is selected as a new set value.

Magnetic disk drive with control of sense current of magnetic head

Embodiments in accordance with present invention provide a magnetic head and a magnetic disc drive capable of preventing a side erase while providing excellent recording characteristics. According to one embodiment, in order to prevent the side erase in an increased skew angle state, a first magnetic pole surface is formed in such a shape that the projection area of the first magnetic pole surface follows a track edge positioned on the boundary side in the track in the state where the first magnetic pole surface is positioned on the track at the innermost periphery thereof included in a first region. Likewise, to prevent the side erase in the increased skew angle state, a second magnetic pole surface is formed in such a shape that the projection area of the second magnetic pole surface follows a track edge positioned on the boundary side with respect to a track in the state where the second magnetic pole surface is positioned on the track at the outermost periphery thereof included in a second region.

Magnetic head and magnetic disc drive

A magnetic read/write apparatus comprises: a recording medium; and a head for writing/reading data to/from each sector on the recording medium; wherein the magnetic read/write apparatus further comprises: a write inhibit slice setting circuit for, when data is written to the recording medium, setting a write inhibit slice for each sector based on the recording state of each sector on the recording medium.

Magnetic read/write apparatus having a write inhibit slice setting circuit

Deterioration in recording performance immediately after the start of recording in a magnetic recording apparatus due to the contraction of the magnetic head element in low atmospheric temperatures is prevented, thus ensuring a stable recording performance irrespective of the ambient temperature. Upon reception of a recording command for first data from a host device, second data already recorded in the same track as that of a data area where information is to be recorded is read and then stored in a memory. Dummy data is then recorded in the data area on the track, and then the first and second data stored in the memory is recorded. Magnetic disc apparatuses for car navigation systems, where stable operation under low temperatures is required, can be provided at low cost.

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Kanagawa, Japan

Hideki Zaitsu