Western Digital Technologies, Inc.

Srinivas Neppalli

William Bernard Boyle

David Christopher Pruett

Raymond Yu

Brian Jones

Edwin Scott Olds

Robert Morelli Fallone

Marcus A Carlson

David M Hamilton

Abedon Madril

Managing data stored in a Data Storage Device (DSD) including a volatile memory and a non-volatile memory including a circular buffer. Metadata stored in the volatile memory is logically divided into blocks of metadata. At least one changed block of metadata is identified that has changed during operation of the DSD and the at least one changed block of metadata is stored in the circular buffer of the non-volatile memory.

Check-pointing of metadata

Managing data stored on media of a Data Storage Device (DSD) using zone relocation. At least a portion of the media is logically divided into a plurality of zones and zones are identified with access counts greater than or equal to a threshold. The access count for each of the identified zones indicates a number of times data in the zone has been read or written. Data is relocated from at least one zone of the identified zones to at least one destination zone on the media to reduce a data access time between the identified zones.

Data management for a data storage device with zone relocation

The present invention is directed to systems and methods for opportunistically defragmenting a data storage device during garbage collection. During garbage collection, valid data is identified and cached in a buffer assigned to the garbage collection process. When the buffer has been filled or reached a threshold, the valid data in the buffer is then coalesced and rewritten back to the data storage medium. In addition, a translation table is reduced by updating its entries to indicate the new locations of the coalesced valid data.

Opportunistic defragmentation during garbage collection

A disk drive comprising a rotatable disk, a head actuated over the disk, and a controller is disclosed. The controller is configured to write a first force unit access write data to the cache as part of the cache data, write the first force unit access write data and a first metadata corresponding to the first force unit access write data to the first location by using the head, transmit a first write complete status to a host, and maintain the first force unit access write data in the cache as part of the cache data. The controller is also configured to store write data as part of the cache data. Furthermore, the controller is configured to write the cache data to a third location, and a metadata corresponding to the cache data to the disk.

Method and apparatus for performing force unit access writes on a disk

Managing data objects in a Data Storage Device (DSD) including a disk and a volatile memory for storing data. A data object is written from the volatile memory in a data object zone of the disk of the DSD. At least one most recent version of a previously written data object is rewritten in the data object zone so that an earlier version of the data object written from the volatile memory does not interrupt a contiguous plurality of most recent versions of data objects stored in the data object zone.

Management of data objects in a data object zone

A data storage device is disclosed including a non-volatile media having a plurality of physical locations for storing user data, each physical location associated with a logical block address (LBA), a translation table having a plurality of entries, each entry having a mapping of one or more LBAs to a corresponding number of physical locations on the non-volatile media. The data storage device further includes control circuitry that divides the translation table into a plurality of segments, each segment including a group of entries corresponding to a range of LBAs, determines a first score for each segment using a first metric, and selects a segment for defragmentation by utilizing the first score for each segment.

Method for selective defragmentation in a data storage device

A data storage device is disclosed including a non-volatile media having a first and a second plurality of physical locations, the first plurality of physical locations storing user data and the non-volatile media storing first metadata associating each of the first plurality of physical locations with a logical block address (LBA), and a mapping table including a mapping of each LBA to a current physical location. The data storage device further includes control circuitry that reads the first metadata to obtain a first plurality of LBAs, reads the mapping table to determine a current physical location for the first plurality of LBAs, and compares the current physical location of each of the first plurality of LBAs to a corresponding one of the first plurality of physical locations to identify valid user data in the first plurality of physical locations for migration into the second plurality of physical locations.

Data storage device using metadata and mapping table to identify valid user data on non-volatile media

A disk drive subsystem is disclosed that implements a process for metadata recovery. Certain embodiments relate to recovery of metadata containing information indicating the physical locations in the disk drive in which host data is stored. In an embodiment, the metadata to be recovered is disposed in sequence with, or in physical association with host data that it describes. Recovery is accomplished by identifying metadata that is valid, but is absent from one or more translation tables containing translation information. Metadata portion can include one or more identifiers that are sequentially related to identifiers included in one or more other metadata portions. Performance improvements can thereby be attained.

Metadata recovery in a disk drive

The embodiments relate to optimizing a defect log of a storage device, such as a disk drive. The defect log may comprise entries for individual locations, such as sectors on a disk, and entries indicating zones. A zone comprises a plurality of locations in the medium of the storage device and may contain adjacent or non-adjacent defects. One or more medium of the storage device may be scanned for defects and locations of these defects are recorded in the defect log. The defect log may then be analyzed to determine if certain number of defects are in proximity to each other, adjacent or non-adjacent, within a zone. If the defects within a zone exceed a threshold, then the defect log may be condensed by coalescing the individual entries of the defects into zone entries. In addition, the defect log may be further condensed by coalescing zone entries of adjacent zones into combined entries.

Condensing a defect scan log for a disk of a disk drive

A disk drive to condense a defect scan log for a disk is disclosed. The disk drive comprises: a disk including a plurality of tracks having a plurality of wedges; a head to perform read operations from the disk including reading defects on the disk; and a processor. The processor controls operations in the disk drive including: determining a plurality of defect zones, wherein each defect zone includes a plurality of physical locations on the disk; detecting defects on the disk; recording the defects into the defect scan log as log entries, wherein the log entries comprise a location parameter related to the defect location on the disk; determining that the number of defects detected in a first defect zone exceed a first threshold; and combining the log entries of the first defect zone into a coalesced log entry.

Growing community of inventors

Irvine, CA, United States of America

Srinivas Neppalli