Matsushita Electric Industrial Co., Ltd.

Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Maxtor Corporation

Kabuhsiki Kaisha Toshiba

Fernando Anibal Zayas

Richard M Ehrlich

Eric R Dunn

Patrick Allen Hery

Thorsten Schmidt

Michael A Chang

Annie Mylang Le

Mine Wonkyung Budiman

Stephen G Paul

Tomas Blazek

Shoichi Aoki

Fred R Hansen

Daniel Tchen

Raghu Gururangan

Unkyong Hand

In a magnetic recording drive that includes a shingled magnetic recording (SMR) region and a conventional magnetic recording (CMR) region, the quantity of validation data that is stored by the CMR region is reduced. In the magnetic recording drive, verification data stored in the CMR region is invalidated under certain circumstances, including when an SMR band is closed, when an SMR band is indicated by a host to be reused, when an SMR band is indicated to be finished, and when a last data track of an SMR has data stored therein.

Handling of verification data in disk drive cache

In a disk drive, when an off-track error occurs during a sequential disk access operation that spans multiple contiguous data tracks, efficient recovery is performed. In an embodiment, the disk access operation (e.g., reading from or writing to a disk) is attempted for all sectors of the sequential disk access operation. The disk access operation is then attempted again for sectors associated with any off-track errors that occurred during the disk access operation. In another embodiment, when an off-track error occurs during a sequential write operation in a shingled magnetic recording drive, the data originally targeted to be written to a first portion is written to a second portion of the data track that follows the first portion. Since no additional revolutions of the disk are needed for data associated with the sequential write operation to be written to the disk.

Disk drive with efficient handling of off-track events during sequential write

When a shingled magnetic recording (SMR) hard disk drive (HDD) performs additional SMR band copy and/or flush operations to ensure that data associated with logical bands that are adjacent or proximate in logical space are stored in physical locations in the SMR HDD that are proximate in physical space. As a result, efficient execution is ensured of read commands that span multiple logical bands of the SMR HDD.

SMR drive that maintains physical locations of bands via flush/copy operations

A data storage device that includes a magnetic storage device selects one or more power states of the magnetic storage device based on a time interval since a most recent time data has been read from or written to the magnetic storage device. The power state of the magnetic storage device can be changed from a higher power consumption state to a lower power consumption state when the time interval exceeds a predetermined value. The power consumption state may be changed from an active servo state to an intermediate power consumption state, a park state, and/or a standby state, depending on the time elapsed since the most recent time data has been read from or written to the magnetic storage device.

Power state change in disk drive based on disk access history

A hybrid drive and associated methods provide low-overhead storage of a hibernation file in the hybrid hard disk drive. During operation, the hybrid drive allocates a portion of solid-state memory in the drive that is large enough to accommodate a hibernation file associated with a host device of the hybrid drive. In addition to the erased memory blocks that are normally present during operation of the hybrid drive, the portion of solid-state memory allocated for accommodating the hibernation file may include over-provisioned memory blocks, blocks used to store a previous hibernation file that has been trimmed, and/or non-dirty blocks.

Low-overhead storage of a hibernation file in a hybrid disk drive

A hybrid drive and associated methods increase the rate at which data are transferred to a nonvolatile storage medium in the hybrid drive. By using a large nonvolatile solid state memory device as cache memory for a magnetic disk drive, a very large number of write commands can be cached and subsequently reordered and executed in an efficient manner. In addition, strategic selection and reordering of only a portion of the write commands stored in the nonvolatile solid state memory device increases efficiency of the reordering process.

Write reordering in a hybrid disk drive

A data storage device that includes a magnetic storage device and a non-magnetic nonvolatile storage device that measures a hit rate of read/write commands that result in accesses to the non-magnetic nonvolatile storage device, and adjusts a length of a time period, such as an idle time, based on the hit rate. The duration of the time period can be set each time the magnetic storage device is accessed. Upon expiration of the time period, if the magnetic storage device has not yet been accessed, the magnetic storage device is changed from a higher power consumption state to a lower power consumption state.

Timing of power state change in a disk drive based on disk access history

A disk drive includes a first flush cache memory location, a second flush cache memory location, and a controller for writing information associated with a flush cache write command alternatively between the first flush cache memory location and the second flush cache memory location.

Disk drive write method

Systems and methods in accordance with embodiments of the present invention can be applied to determine the position of a ramp relative to an actuator. In one embodiment, a system in accordance with the present invention includes a rotatable medium having a first track assigned to a track located a distance from the ramp, rather than a distance from an average acquire track, thereby maximizing the size of a data region. A track density can be reduced for a given hard disk drive capacity, or alternatively the hard disk drive capacity can be maximized for a given track density.

System and method for optimizing track spacing across a stroke

The present invention comprises an implementation of a variable data TPI hard drive system. In one embodiment, the system is implemented by configuring a group of servo tracks in a radial direction for a hard drive media. The group is comprised of an integral number of servo tracks that is constant throughout the drive device. The number of data tracks in a group is also an integer but will vary for each surface according to the head used for R/W operations for each media surface. Group boundaries coincide with media surface R/W zone boundaries. The groups are accessed in hard drives having multiple surfaces in a serpentine manner. Data tracks per group are reduced from what is achievable to produce desired target capacities.

Method for constrained implementation of variable data TPI

Constrained implementation of variable data TPI

The initial attempt to servowrite a wedge in the final pattern may fail due to disk defects and a retry of servowriting the failed wedge is usually attempted. The current invention shifts the position of the final wedge during at least one such servowriting retry attempt. Since a final wedge position different from a previous self servowriting attempt is adopted, potential defects on the surface of the media can possibly be avoided and the success rate of the servowriting retry attempt can be improved. In practice, this involves carrying a count of failed wedges during the servowrite process and if it exceeds a threshold level, then the wedge pattern is shifted in position and the servowrite process starts again. This can be repeated for many shift positions. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Systems and methods for self-servowriting with improved retry position of wedges

Methods and computer program products for determining accurate estimates of coil resistance are provided. Current differences between pairs of current values are determined. Additionally, voltage differences between pairs of actuator coil voltages (corresponding to the current values) and angular velocity differences between pairs of angular velocities are determined. Coil resistance is estimated based on the current differences, the voltage differences and the angular velocity differences. These coil resistance estimates can be useful for accurately estimating actuator coil, actuator arm and/or head velocity.

Accurate tracking of coil resistance based on current, voltage and angular velocity

A method and apparatus for reducing seek acoustics in a disk drive using feedback during large current transitions is provided. A desired transition profile, which uses feedback, is followed in order to smoothen transitions of a commanded current profile that is supplied to a VCM for moving a head relative to a disk surface during a seek operation. Linear interpolation is used to provide feedback for following the desired transition profile.

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Loveland, CO, United States of America

Fernando Anibal Zayas