Western Digital Technologies, Inc.

Jonathan V Nguyen

Jie Yu

Gregory B Thelin

John Yin Kwong Li

Teddy T C Chen

Guoxiao Guo

Duc T Phan

Michael Stephen Rothberg

Hanan Kupferman

Alain Chahwan

Dalwinder Singh

Teik Ee Yeo

Hien T Chu

Aswartha Narayana

Eugene Chun-Tsing Wu

Jinsheng Bill Jang

Saied Tamaddon-Dallal

Travis E Ell

Toviah N Hirschberg

Gary Gaoxiang Zhu

Tuong M Vu

Hoa V Le

Virat Thantrakul

Example implementations described herein are related to methods for dynamically throttling host commands (up or down) to disk drives that include cache memory and rotating media, based on environmental conditions and/or drain rate from the cache memory to the rotating media, to provide consistent throughput for extended periods of time, and to avoid dramatic swings in performance from the pre-saturation state to the post-saturation state. The example implementations may be further extended to dynamically throttling host commands to devices that have HDD and SSD portions.

Dynamically throttling host commands to disk drives

An electronic device is disclosed comprising an acceleration sensor operable to generate an acceleration signal, and a free fall detector operable to detect a free fall event in response to the acceleration signal. A frequency response of the acceleration signal is measured, and the free fall detector is disabled when a magnitude of the frequency response within one of a plurality of frequency bands exceeds a threshold, wherein each frequency band corresponds to one of a plurality of normal operating modes.

Electronic device avoiding false detection of free fall event based on detected operating modes

A disk drive for implementing a head switch operation is disclosed. The disk drive comprises: an actuator; a first head and a second head attached to the actuator; a disk having a plurality of tracks; and a processor. The processor controls operations in the disk drive including: executing a head switch command from the first head to the second head; determining that a sync-up operation is not successful for the second head at a first track; applying a torque to the actuator to move the second head to a second track; and determining that the sync-up operation is successful.

Head switch operation for a disk drive

A disk drive is disclosed comprising a plurality of servo sectors that define a plurality of tracks, and a head comprising a read element radially offset from a write element. The read element is positioned over a first track, and the first track is read to generate first read wedge repeatable runout (WRRO) values. A first seek operation of the head positions the read element over a second track, and the second track is read to generate first write WRRO values. The first write WRRO values are used to write the first read WRRO values to the first track. A second seek operation of the head positions the read element over a third track, and the third track is read to generate second write WRRO values. The second write WRRO values are used to write the first write WRRO values to the second track.

Disk drive writing wedge RRO values in a butterfly pattern

A disk drive operable with first and second servo patterns in a perpendicular media recording (PMR) environment is disclosed. The disk drive comprises a head operable with a perpendicular flux, a disk, and a servo controller. The disk includes a plurality of tracks, wherein each track has a plurality of servo sectors utilized in seek operations. The servo sectors of the disk include a first servo pattern between one of an inner diameter (ID) or an outer diameter (OD) of the disk and a middle diameter (MD) of the disk, respectively, and a second servo pattern between the other of the OD or the ID of the disk and the MD of the disk, respectively. The servo controller operates in a first mode when seeking within one of the first or second servo patterns and a second mode when seeking between the first servo pattern and the second servo pattern.

Disk drive operable with first and second servo patterns in a perpendicular media recording environment

Disclosed is a disk drive having a disk, a masked read-only memory (ROM) device, a reprogrammable nonvolatile memory device, and a microprocessor for executing program code. The disk has a magnetic data storage surface with embedded servo wedges for defining data storage tracks including reserve tracks. The masked ROM device stores program code for implementing a spindle motor controller, program code for implementing a portion of a servo controller for track following along a data storage track, and program code for implementing a portion of a disk controller for controlling writing disk data to and reading disk data from the reserve tracks. The reprogrammable nonvolatile memory device stores data parameters relating to the disk drive's configuration. The reserve tracks store program code for implementing a cache control system for controlling caching of disk data in a cache memory.

Disk drive and method having cost-effective storage of the disk drive's internal program code

A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors. The disk drive further comprises a plurality of heads, such as a top head and a bottom head. Control circuitry within the disk drive determines a head-switch preheat period used to format the disk. The head-switch preheat period is calibrated by selecting one of the heads to write a test pattern to the disk, and then preheating the selected head for a preheat period prior to reading the test pattern from the disk to generate a read signal. The head-switch preheat period is determined for the selected head in response to the read signal.

Disk drive determining a head-switch preheat period used to format a disk

A disk drive is disclosed which pre-computes first seek parameters to seek to a continuation track storing read-ahead data, and second seek parameters to seek to a target track of a next command. An abort window is also computed for aborting a read-ahead operation early in order to seek to the target track of the next command. If the head enters the abort window, the disk drive is programmed with the second seek parameters to seek to the target track of the next command. If the read-ahead operation requires a seek to the continuation track prior to the head entering the abort window, the disk drive is programmed with the first seek parameters to seek to the continuation track.

Disk drive pre-computing seek parameters for a continuation track and a next command to facilitate continuing a read-ahead or aborting the read-ahead

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Laguna Niguel, CA, United States of America

Jonathan V Nguyen