Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Western Digital Technologies, Inc.

Christopher David Wiederholt

Satyajit Patwardhan

Ryohheita Hattori

Roel Dieron

Adam Michael Espeseth

Quan-chiu Harry Lam

Kris Victor Schouterden

Hideaki Ito

Douglas Michael Zuercher

Brian Lee Morger

Louise Ann Marier

Shravankumar Girish Bhat

Joseph Silva

Guo Mian

Robert Anton Steinbach

Indukumar Kalahasthi

Trevor James Briggs

Example systems, data storage devices, and methods to provide data protection during concurrent operations for multiple actuator data storage devices are described. The data storage device includes a plurality of actuators configured to actuate a plurality of heads over different subsets of a plurality of disk surfaces. Responsive to receiving a write command for one of the actuators, the coupling state with at least one other of the actuators is determined and execution of write commands is inhibited if the coupling state indicates a possible coupling event. The inhibit of the write commands in the presence of coupling events may prevent off-track writes and protect data.

Data protection during concurrent operations for multiple actuator data storage devices

A disk drive has a head fly-height actuator wherein the head-disk spacing is controlled as a function of both the track, and the sector or sectors within the track, where data is to be read or written. The fly-height actuator may be a thermal actuator comprising a heater located on the slider near the read/write head. The fly-height controller (FHC) for the thermal actuator stores band control signal (BCS) values representative of heater power (Hp) to be applied to the thermal actuator when reading or writing to a data track in the associated band of tracks. The FHC also either calculates from a programmed equation or recalls sector control signal (SCS) values representative of an Hp increment to be applied to the thermal actuator depending on the sector or sectors where data is to be written. The FHC sums the appropriate SCS value with the appropriate BCS value to achieve the desired Hp, resulting in the optimal fly-height not only for the selected band but also for the selected sector or sectors.

Disk drive with head fly-height compensation for disk surface variations

A method is presented for writing data to a surface of a magnetic disk in a disk drive. The method includes determining a number of sector groups into which sectors of the data to be written will be grouped, loading registers with current values, kick-latching values, and precompensation values for each of said sector groups, and applying the current values, kick-latching values, and precompensation values for each of the sector groups to the write head while writing data to the sector groups of the recording media.

Method for precompensation/write-current latching to improve error rate

A disk drive has a resistive heater located near the read/write head as a thermal fly-height actuator and uses an improved method for operating the fly-height actuator. As part of the method, the heater may be deactivated during a seek to minimize the risk of head-disk contacts. When a write command is received, a level of heater power is applied to pre-heat the write head prior to writing the initial data sectors. This pre-heating heater power level may be higher than the power level used for writing. Then when writing commences, the lower power level is applied to the heater so the write head has the optimal head-disk spacing during the writing of all the data sectors, including the initial data sectors. Even though the heater may be deactivated during the seek the controller can initiate pre-heating during the last portion of the seek before the write head has reached the target track.

Disk drive with improved method for operating a thermal head fly-height actuator

A method and apparatus is provided which reduces the equipment and time requirements for hard disk drive performance testing during manufacturing. This invention executes self-contained performance testing code that resides within the drive's manufacturing firmware, rather than relying on external testers. The invention involves exercising the drive's enqueue, dequeue, and command execution firmware, as well as the physical process of reading and writing data by simulating the host interface in code. The invention enqueues commands that typify the desired workload, allows a command ordering algorithm to sort the commands for execution, and allows the drive side code to execute the commands just as if an external host interface were attached. The invention is advantageous because the performance testing can be done by only applying power to the drive. The present invention also lends itself to performance tuning that can be done in manufacturing, to reduce drive-to-drive performance variations.

Method and apparatus for automated analysis of hard disk drive performance

A data storage device and method for improving the performance of data storage devices examines a command queue and performs data transfers to memory within the device before prior commands have completed. A process running in the idle loop of the controller in the storage device checks the queue for write requests and if a cache space within a dual-port cache to hold the transfer data is available, the data transfer portion of the transfer is completed, while the device is still waiting for completion of prior commands in the queue, and data transfers are completing from the cache to the physical media for the prior command.

Data storage device and method for reducing write misses by completing transfer to a dual-port cache before initiating a disk write of the data from the cache

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Rochester, MN, United States of America

Christopher David Wiederholt