Abstract: Apparatus and method for managing metadata in a data storage device. In some embodiments, a metadata object has entries that describe data sets stored in a non-volatile write cache. During an archival (persistence) operation, the metadata object is divided into portions, and the portions are copied in turn to a non-volatile memory at a rate that maintains a measured latency within a predetermined threshold. A journal is formed of time-ordered entries that describe changes to the metadata object after the copying of the associated portions to the non-volatile memory. The journal is subsequently stored to the non-volatile memory, and may be subsequently combined with the previously stored portions to recreate the metadata object in a local memory. The measured performance latency may be related to a specified customer command completion time (CCT) for host commands.

Abstract: An exemplary write method disclosed herein includes receiving a request to write data to a consecutive sequence of logical block addresses (LBAs); identifying a first non-contiguous sequence of data tracks mapped to a first portion of the consecutive sequence of LBAs; and identifying a second non-contiguous sequence of data tracks mapped to a second portion of the consecutive sequence of LBAs, where the second portion sequentially follows the first portion. The method further includes writing the data of the second portion of the consecutive sequence of LBAs to the first non-contiguous sequence of data tracks during a first pass of a transducer head through the radial zone and writing the data of the first portion of the consecutive sequence of LBAs to the second non-contiguous sequence of data tracks during a second, subsequent pass of the transducer head through the radial zone.

Abstract: Implementations disclosed herein provide a method comprising detecting a power supply status, determining a media cache cleaning scheme based on the detected power supply status, and performing the determined cleaning scheme until a predetermined threshold is reached.

Abstract: The disclosed technology provides a method that improves CCT in SMR device systems. In one implementation, the method comprises writing data to a shingled magnetic recording (SMR) band in a storage device, determining whether an off-track write has occurred, identifying unsafe written data in response to determining that an off-track write has occurred, determining whether caching space is available upon identifying unsafe written data, continue writing data to the SMR band without a write retry upon determining that caching space is available, and writing unsafe written data to the available caching space. In another implementation, the method comprises receiving a request to repair an encroached track in an SMR band, recovering encroached data to a dynamic random-access memory, determining whether caching space is available, writing the recovered data to the available caching space upon determining that caching space is available, and merging other cached data in the SMR band.

Abstract: Apparatus and method for managing metadata in a data storage device. In some embodiments, a metadata object has entries that describe data sets stored in a non-volatile write cache. During an archival (persistence) operation, the metadata object is divided into portions, and the portions are copied in turn to a non-volatile memory at a rate that maintains a measured latency within a predetermined threshold. A journal is formed of time-ordered entries that describe changes to the metadata object after the copying of the associated portions to the non-volatile memory. The journal is subsequently stored to the non-volatile memory, and may be subsequently combined with the previously stored portions to recreate the metadata object in a local memory. The measured performance latency may be related to a specified customer command completion time (CCT) for host commands.

Abstract: Systems and methods for maximizing shingled magnetic recording (SMR) drive capacity are described. In one embodiment, the SMR drive may include a main store to store user-accessible data, a media cache and media scratchpad to store internal data temporarily for internal operations, and a storage controller to process read and write requests. In some cases, the main store comprises a shingled media partition and an unshingled media partition. The storage controller may designate one or more data tracks from the shingled media partition as temporary data track guard bands. In some embodiments, a track range is selected based at least in part on at least one of an amount of data in the media cache, a size of the new data in the media cache, and an association between the new data in the media cache and data currently stored within the selected track range.

Abstract: A data storage device includes a media cache and a main data store optimized for sequential reads and organized into bands. When the data storage device receives a read request from a host computing system, the requested data may be fragmented across the media cache and the main data store, causing constrained read throughput. Band rewrite operations to improve read throughput are selected based on a hit tracking list including a hit counter associated with each band on the main data store. The hit counter tracks the number of times a host computing system has requested data in logical block addresses corresponding to the various bands. The data storage device may select bands for band rewrite operations based on the number of hits in the associated hit tracking counters.

Abstract: Embodiments described herein are operable with a storage device. In one embodiment, a method provides for buffering first portions of incoming sequential data from a plurality of channels in a buffer, and identifying locations of the storage device to store the first portions of the incoming sequential data. The method also provides for directly writing the first portions of the incoming sequential data from the buffer to the identified locations of the storage device.

Abstract: The disclosed technology provides a system and method that improves command completion time in a shingled magnetic recording device system. In one implementation, the system and method include receiving a write command to write data to a first track in a band in a recording medium, seeking to a first track, reducing an on-cylinder limit (OCLIM) from a default OCLIM to a reduced OCLIM by a predetermined amount on the first track, performing write operations on the first track with the reduced OCLIM, and determining if a transfer of data to the first track band in the write operations has been substantially completed. Upon determining that a transfer of data to the first track in the write operations has been substantially completed, the OCLIM is restored from a reduced OCLIM to a default OCLIM and write operations are performed on tracks adjacent to the first track.

Abstract: Apparatus and method for managing a media cache of a data storage device. In some embodiments, a media cache master table is maintained in a memory as a data structure having a plurality of entries that describe data sets stored in a non-volatile media cache memory. A first timecode stamp value is written to respective first and second locations in the table at the commencement of a data transfer operation to transfer data associated with the plurality of entries in the table. The first location is updated with a new, second timecode stamp value responsive to detection of an error condition that interrupts the data transfer operation. An error recovery operation is subsequently performed responsive to a detected mismatch between the timecode stamp values in the first and second locations.

Abstract: Apparatus and method for managing data in a hybrid data storage device. In some embodiments, a hybrid data storage device operates in a normal mode in which data transfer commands received from a host device are serviced by a top level controller circuit which directs a first subset of the received data transfer commands to a non-volatile rotatable recording memory and a second subset of the received data transfer commands are directed to a non-volatile solid-state memory. The controller circuit transitions to a performance mode responsive to a detected first parameter so that subsequently received data transfer commands are directed exclusively to the solid-state memory. The controller circuit terminates the performance mode and resumes the normal mode responsive to a detected second parameter.

Abstract: Apparatus and method for managing a media cache of a data storage device. In some embodiments, a media cache master table is maintained in a memory as a data structure having a plurality of entries that describe data sets stored in a non-volatile media cache memory. A first timecode stamp value is written to respective first and second locations in the table at the commencement of a data transfer operation to transfer data associated with the plurality of entries in the table. The first location is updated with a new, second timecode stamp value responsive to detection of an error condition that interrupts the data transfer operation. An error recovery operation is subsequently performed responsive to a detected mismatch between the timecode stamp values in the first and second locations.

Abstract: A method includes storing a data group in a first zone of a plurality of radial zones of a data storage disc. Each different one of the plurality of zones has a different throughput level. The method further includes obtaining information related to an access frequency of the data group stored in the first zone of the plurality of zones. Based on the information related to the access frequency of the data group and the different throughput levels of the different zones, a determination is made as to whether to migrate the data group from the first zone of the plurality of zones to a second zone of the plurality of zones.

Abstract: Systems and methods for maximizing shingled magnetic recording (SMR) drive capacity are described. In one embodiment, the SMR drive may include a main store to store user-accessible data, a media cache and media scratchpad to store internal data temporarily for internal operations, and a storage controller to process read and write requests. In some cases, the main store comprises a shingled media partition and an unshingled media partition. The storage controller may designate one or more data tracks from the shingled media partition as temporary data track guard bands. In some embodiments, a track range is selected based at least in part on at least one of an amount of data in the media cache, a size of the new data in the media cache, and an association between the new data in the media cache and data currently stored within the selected track range.

Abstract: An apparatus can include: (i) a network controller in a mesh network, the network controller being configured to send a beacon in a predetermined beacon slot in a broadcast manner, where the beacon includes a slot allocation state of the mesh network; and (ii) a plurality of node devices, where each node device is configured to synchronize according to the beacon, and to send a data packet within a corresponding fixed time slot according to the slot allocation state, where each of the fixed time slots corresponds to only one of the plurality of node devices.

Abstract: Systems and methods of generating random values based on random components of the noise are presented. A signal having at least a noise component(s) can be received and one or more random values can be calculated from the noise component(s). In some examples, noise can be received from a random source and common mode portions of the data can be filtered. A data channel can then process the noise to produce random data, which can be further processed by security circuits to generate random values, seed values, random numbers, and other values.

Abstract: Systems and methods for maximizing shingled magnetic recording (SMR) drive capacity are described. In one embodiment, the SMR drive may include a main store to store user-accessible data, a media cache and media scratchpad to store internal data temporarily for internal operations, and a storage controller to process read and write requests. In some cases, the main store comprises a shingled media partition and an unshingled media partition. The storage controller may designate one or more data tracks from the shingled media partition as temporary data track guard bands. In some embodiments, a track range is selected based at least in part on at least one of an amount of data in the media cache, a size of the new data in the media cache, and an association between the new data in the media cache and data currently stored within the selected track range.

Abstract: Systems and methods for maximizing shingled magnetic recording (SMR) drive capacity are described. In one embodiment, the SMR drive may include a main store to store user-accessible data, a media cache and media scratchpad to store internal data temporarily for internal operations, and a storage controller to process read and write requests. In some cases, the main store comprises a shingled media partition and an unshingled media partition. The storage controller may designate one or more data tracks from the shingled media partition as temporary data track guard bands. In some embodiments, a track range is selected based at least in part on at least one of an amount of data in the media cache, a size of the new data in the media cache, and an association between the new data in the media cache and data currently stored within the selected track range.

Abstract: Apparatus and method for managing a media cache through the monitoring of operational vibration of a data storage device. In some embodiments, a non-volatile media cache of the data storage device is partitioned into at least first and second zones having different data recording characteristics. Input data are received for storage in a non-volatile main memory of the data storage device. An amount of operational vibration associated with the data storage device is measured. The input data are stored in a selected one of the first or second zones of the media cache prior to transfer to the main memory responsive to a comparison of the measured amount of operational vibration to a predetermined operational vibration threshold.

Abstract: Systems and methods are disclosed for detecting shingled overwrite errors. When a read error is encountered when reading from shingled recording tracks, a processor may determine whether the read error is an error caused by shingled overwriting. The processor may determine whether the read error is caused by shingled overwriting by determining read signal quality of one or more sectors preceding the read error, such as based on a bit error count or bit error ratio (BER), and comparing the read signal quality to a threshold value. The processor may determine that the read error is caused by shingled overwriting when the read signal quality value is lower than the threshold.