Seagate Technology Incorporated

Timothy Francis Ellis

Alexei Hiram Sacks

Reed David Hanson

Puskal Prasad Pokharel

David S Kuo

John Christopher Morris

Joshua Ward Christensen

James E Angelo

Serge Jacques Fayeulle

Nathaniel Boyd Wilson

Mukund Channagiri Rao

Gary Ernest Hillukka

Mehmet Fatih Erden

Thomas C Zirps

Brian Robert Pollock

Richard Lyle Keizer

Jason Bellorado

Ara Patapoutian

Bruce Douglas Buch

Riyan Alex Mendonsa

Karl Arnold Belser

David L Schell

William Michael Radich

Barmeshwar Vikramaditya

John Charles Purkett

Zheng Wang

Dustin Mark Cvancara

Thomas Lee Schick

Patrick J Korkowski

Samir Mittal

Justin Won

Christopher Thomas Settje

Ravi Hebbar

Peng Yan

Steven Alan Koldewyn

Two or more data values are received from one or more sensors of a hard disk drive. The two or more data values are indicative of a fly height of a recording head of the hard disk drive. The two or more data values are input into a machine-learning processor during operation of the hard disk drive. A fly height of the recording head during the operation of the hard drive head is adjusted based on an output of the machine learning processor.

Estimating recording head fly height using machine learning

Systems and methods for servo zone transition optimization are described. In one embodiment, the storage system device includes a disk drive and a controller. In some embodiments, the controller may be configured to assess at least one operation of a read/write head of the disk drive; and format, based at least in part on the assessing of the read/write head, a disk surface of the disk drive with a first servo zone, a second servo zone, and an overlap region extending between a start point of the second servo zone and an end point of the first servo zone. In some cases, the overlap region starts towards a disk inner diameter (ID) and ends towards a disk outer diameter (OD).

Servo zone transition optimization for disk drives

Servo zone transition optimization for magnetic disk recording devices

An apparatus may include a preamplifier configured to be connected to a plurality of magnetic read/write heads, wherein each of the magnetic read/write heads includes a read sensor to read data from a disc and a write element to write data to the disc. The preamplifier may include a first set of registers configured to indicate a first head of the plurality of magnetic read/write heads that is selected for reading data, a second set of registers configured to indicate a second head of the plurality of magnetic read/write heads that is selected for reading data, an input line configured to receive a control signal to activate reading data from the first head substantially simultaneously with reading data from the second head, a first output to provide data from the first head, and a second output to provide data from the second head.

Independent head, dual reader control logic

First and second read channel logic circuits are configured to process first and second signals communicated from respective first and second readers that simultaneously read from a magnetic disk. A first servo detection circuit generates a primary servo gate based on timing data from the first reader. The primary servo gate is used for processing the first signal via the first read channel logic. A second servo detection circuit that generates a secondary servo gate based on the primary servo gate and an adjustment value. The secondary servo gate is used for processing the second signal via the second read channel logic.

Primary and secondary servo timing gates used with simultaneously operating readers

Methods and apparatuses for modulating a position error signal detection gate signal responsive to a track crossing velocity are discussed. The position error signal can be used to detect position information. A track crossing velocity can be estimated and then used via the modulating. Phase errors due to the track crossing velocity can be minimized.

Position error signal (PES) detection

The disclosure is related to systems and methods of compensating for interference via a multi-reader system. A transducer or read/write head may include a write element and multiple read elements. A compensation circuit can be configured to process read signals from the multiple read elements to reduce noise within the read signals, such as caused by the writer being simultaneously active or for other reasons. The read signals may be combined to produce a compensated read signal that has less noise than the original read signals.

Compensating for interference via a multi-reader system

A circuit may be configured to reduce the amount of space used on a storage device when a transducer having a reader and writer passes from a writable data field to a read-only field by enabling both the reader and writer simultaneously. The circuit can be configured to reduce to a threshold level the noise on a read signal that can occur when the reader is over a read-only field and the writer is over a writable data field, and can ignore the read data when both the writer and reader are enabled simultaneously over a writable data field.

Read read-only fields while writing

Systems and methods are disclosed for writable servo zone overlap regions on a disc memory. An apparatus may comprise a controller configured to determine a servo gate (sgate) timing for an overlap zone including servo patterns of a first servo super zone and a second servo super zone of a disc memory, the sgate timing based on servo pattern timing for the first servo super zone and the second servo super zone. The controller may initiate writing to the overlap zone based on the sgate timing. The controller may also reduce the impact of servo pattern frequency change between zones by calculating a trajectory error prior to the crossing, and providing 1/X of the trajectory error into a servo feedback loop for a following X servo sampling points.

Writable servo overlap zones

A method is disclosed that includes measuring a first amplitude and a second amplitude in a servo pattern signal derived from a transducer head interacting with a medium; and providing an indication of a change in a spacing distance between the head and the medium, wherein the change in the spacing is evaluated using a spacing relation derived from a ratio of the first harmonic amplitude and the second harmonic amplitude.

Using servo data harmonics to monitor head-medium spacing

Compensation for repeated runout (RRO) error, such as in a data storage device servo circuit, is preferably carried out by obtaining a population distribution of RRO error values from at least selected ones of a subset of tracks. An RRO error compensation value is determined for each one of the subset of tracks when a variance characteristic of said population distribution meets a selected criterion. Preferably, a first track of a storage medium has a servo field at a first angular position on the medium, a repeated runout (RRO) error compensation field at a second angular position on the medium, and a user data field at a third angular position on the medium. An immediately adjacent second track preferably has a servo field at the first angular position and a user data field at the second angular position in lieu of an RRO error compensation field.

Zone based repeated runout error compensation

An apparatus and method for compensation for variation in timing skew in a disc drive having at least one rotating disc is provided. A first head is positioned over a first disc surface and a second head is positioned over a second disc surface. The first disc surface includes a track having a first plurality of sectors and the second disc surface includes a track having a second plurality of sectors. Each sector of the second plurality of the sectors corresponds to a different sector of the first plurality of sectors, thereby forming a plurality of pairs of corresponding sectors. A timing skew value for each pair of corresponding sectors is computed to obtain a sequence of timing skew values. Data related to the sequence of timing skew values is utilized to compensate for variation in timing skew.

Compensation for variation in timing skew in a disc drive data storage system

Method and apparatus for certifying servo sectors on recording surfaces of a disc stack of a data storage device to promote servo sector alignment among the various recording surfaces. A reference servo sector pattern is written to a first recording surface, the reference pattern comprising a plurality of angularly spaced apart servo sectors. Multiple interleaved sets of servo sector patterns are written to each of the remaining recording surfaces, each interleaved pattern respectively comprising a plurality of angularly spaced apart servo sectors. A selected interleaved pattern is identified from each of the remaining surfaces that provides a desired alignment with the reference servo sector pattern, and the non-selected servo sector patterns are overwritten. The servo patterns can be written to the discs prior to installation using a multiple disc writing (MDW) station, or after installation of the discs into the data storage device using a servo track writing (STW) station.

Writing multiple servo sector patterns to improve servo sector alignment on multiple surfaces

A method of manufacturing a magnetic recording medium, comprises steps of providing a non-magnetic substrate for a magnetic medium, the substrate including at least one major surface having a contact start/stop (CSS) or landing zone and a data zone; and forming a pattern of recesses in the substrate surface in said CSS or landing zone by embossing utilizing a stamper having a surface including a negative image pattern of said pattern of recesses. Embodiments of the invention include magnetic media comprising a non-magnetic substrate including at least one major surface having a contact start/stop (CSS) or landing zone and a data zone, said substrate surface in said CSS or landing zone comprising an embossed pattern of recesses. In addition, the data zone of the substrate surface may include an embossed servo pattern formed simultaneously with the embossed pattern of recesses formed in the landing zone.

Recording media with mechanically patterned landing zone

An apparatus comprises a data storage medium having a plurality of servo sectors and a plurality of data sectors, wherein each of the servo sectors includes a phase locked loop field and a track identification field, a controller for controlling the position of a recording head with respect to the data storage medium, and a servo demodulator for recovering timing information from both the phase locked loop field and the track identification field, and for producing a timing estimate. The method performed by the apparatus is also included.

Growing community of inventors

Tonka Bay, MN, United States of America

Timothy Francis Ellis