Irvine, CA, United States
Irvine, CA, United States

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A data storage device comprises a non-volatile memory comprising a plurality of blocks, each configured to store a plurality of physical pages at predetermined physical locations. A controller programs and reads data stored in a plurality of logical pages. A volatile memory comprises a logical-to-physical address translation map configured to enabling determination of the physical location, within one or more physical pages, of the data stored in each logical page. A plurality of journals may be stored, each comprising a plurality of entries associating one or more physical pages to each logical page. At startup, the controller may read at least some of the plurality of journals in an order and rebuild the map; indicate a readiness to service data access commands after the map is rebuilt; rebuild a table from the map and, based thereon, select block(s) for garbage collection after having indicated the readiness to process the commands.


Patent
Western Digital Technologies | Date: 2016-08-29

Systems and methods are disclosed for managing program code in a computing device, such as an embedded system. In a computing device, a non-volatile flash memory stores program code comprising initialization code designed to be executed a single time during device booting, main program code separate from the initialization code, and main code loader code designed to direct a controller of the computing device to load the main program code from the flash memory to the RAM when executed by the controller. The controller loads the initialization code and the main code loader code to first and second adjacent portions of the RAM, respectively, and loads the main program code, separately from the initialization code, to a third portion of the RAM at least partially overlapping the first portion but not overlapping the second portion, thereby at least partially overwriting the initialization code.


Patent
Western Digital Technologies | Date: 2016-08-29

Embodiments of compression and formatting of data for data storage systems are disclosed. In some embodiments, a data storage system can compress fixed sized data before storing it on a media and format obtained variable sized compressed data for storing on the media that typically has fixed size storage granularity. One or more modules compress the incoming host data and create an output stream of fixed sized storage units that contain compressed data. The storage units are stored on the media. Capacity, reliability, and performance are thereby increased.


Patent
Western Digital Technologies and IntriPlex Technologies Inc. | Date: 2016-08-16

A novel method, for fabricating a tolerance ring suitable for use in applications such as an actuator assembly for a disk drive, is disclosed. The tolerance ring may be fabricated by steps including stamping a sheet metal section from a strip of sheet metal that has first and second edges that are parallel to a strip axis. A leading axial edge may be rounded from an inner major face and from an outer major face. A plurality of protrusions may be formed from the first major face. The sheet metal section may be bent into a substantially cylindrical shape having a central axis that is normal to the strip axis.


Patent
Western Digital Technologies | Date: 2016-09-06

A system according to one embodiment includes a pinned layer; a spacer layer above the pinned layer; a free layer above the spacer layer; a heating device, for heating the free layer to induce a paramagnetic thermal instability in the free layer whereby a magnetization of the free layer randomly switches between different detectable magnetic states upon heating thereof; and a magnetoresistance detection circuit for detecting an instantaneous magnetic state of the free layer.


Patent
Western Digital Technologies | Date: 2016-06-06

Embodiments of the invention include systems and methods for recovering the system status and maintaining drive coherency after an unexpected power loss. In particular, these systems and methods reduce overhead for maintaining drive coherency by providing for pre-allocation of groups of write addresses and recording the pre-allocated groups of addresses to the non-volatile memory. Write processes can write to the pre-allocated group of addresses while the next group of addresses are pre-allocated and recorded to non-volatile memory.


A power system includes a first charge pump configured to supply power, and control circuitry coupled to the first charge pump. The control circuitry is operable to receive a signal indicating whether a second change pump is turning on. If the first charge pump is about to be turned on and the signal indicates that the second charge pump is turning on, the control circuitry is operable to prevent an output, of first charge pump from substantially aligning with an output of the second charge pump.


Systems and methods for correcting read/write overlay errors in the manufacture of magnetic transducers for storage drives are provided. One such system includes a twisting tool configured to receive and secure a row bar having an elongated rectangular block shape and including a plurality of magnetic transducers spaced apart along a length of the row bar, and where the twisting tool is configured to twist the row bar at a plurality of areas along the length of the row bar.


A data storage device is disclosed comprising a spindle motor configured to rotate a disk, wherein the spindle motor comprises a plurality of windings. The windings are commutated based on a commutation sequence while applying a driving voltage to each winding, wherein the driving voltage comprises an operating amplitude during normal operation. When a supply voltage falls below a threshold, the spindle motor is configured into a power generator by at least reducing the amplitude of the driving voltage to substantially zero and then incrementally increasing the amplitude of the driving voltage by at least two steps toward the operating amplitude.


Patent
Western Digital Technologies | Date: 2016-08-12

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by a plurality of servo sectors. An estimated track ID is generated and a plurality of proximate track IDs is generated having values proximate the estimated track ID. A set of Gray codes is generated each corresponding to the estimated track ID and the proximate track IDs, wherein each Gray code in the set of Gray codes comprises N bits, and M bits out of a high order of the N bits comprise the same value. A recorded Gray code is detected in a first servo sector to generate a detected Gray code, and an error in the detected Gray code is corrected by inverting at least one bit in the detected Gray code comprising a value that is different from the value of the corresponding bit in the M bits.

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