Fast partial erasure for drive sanitization

    公开(公告)号:US12131758B2

    公开(公告)日:2024-10-29

    申请号:US18223896

    申请日:2023-07-19

    CPC classification number: G11B5/2654 G11B5/5547

    Abstract: A method involves determining a threshold error rate that will result on data stored on a magnetic disk surface of a disk drive being unrecoverable. The method also involves determining a seek velocity that will overwrite sufficient portions of the data such the data will exhibit at least the threshold error rate. The disk drive performs at least one traversal of the magnetic disk surface with a head of the disk drive that emits an erase field during the at least one traversal at the seek velocity. The at least one traversal sanitizes the data.

    System and method for managing off-track read retry

    公开(公告)号:US11295777B1

    公开(公告)日:2022-04-05

    申请号:US17086003

    申请日:2020-10-30

    Inventor: Xiong Liu Quan Li

    Abstract: The technology disclosed herein pertains to a system and method for managing off-track retry. An implementation of a method of determining offset direction for read off-track retry includes storing analog to digital converter (ADC) values of data read from a data sector by a data reader in a read channel buffer, calculating an indicator value of the distribution of the ADC values, determining an amount of offset for the data reader based on the indicator value, and moving the data reader by the amount of offset before performing a read retry operation.

    Write current switching using an effective size of a media thermal spot produced by a heat-assisted magnetic storage device

    公开(公告)号:US10885932B1

    公开(公告)日:2021-01-05

    申请号:US16798739

    申请日:2020-02-24

    Inventor: Xiong Liu Quan Li

    Abstract: A heat-assisted magnetic recording device includes a write pole positionable adjacent a magnetic recording medium and configured to write data to the medium. A near-field transducer is situated proximate the write pole and configured to produce a thermal spot on the medium. A channel circuit is configured to generate a sequence of symbols having a length of nT, where T is a channel clock rate and n is an integer over a predetermined range. A write driver is configured to apply bi-directional write currents to the write pole to record the sequence of symbols at a location of the thermal spot on the medium, wherein a duration of applying the write currents to the write pole by the write driver is dependent on a length of the sequence of symbols and the effective thermal spot size.

    Write current switching in a data storage device using an effective footprint of a write pole

    公开(公告)号:US10446184B1

    公开(公告)日:2019-10-15

    申请号:US16221839

    申请日:2018-12-17

    Abstract: A sequence of symbols is generated to describe a set of write data, the symbols having a length of nT, where T is a channel clock rate and n is an integer over a predetermined range. Bi-directional write currents are applied to a write pole to record the sequence of symbols to a magnetic storage medium. The write pole has an effective footprint with a downtrack length of mT, where m is an integer. The write currents are switched between a first rail current and a second rail current for alternating symbols, the write currents further transitioning to an intermediate current value for at least one channel clock period for symbols longer than 1T. Write currents are applied to the write pole when recording symbols having a length longer than mT using the effective footprint of the write pole as an interval.

    DATA MANAGEMENT METHOD FOR STORAGE MEDIA
    5.
    发明申请

    公开(公告)号:US20190278594A1

    公开(公告)日:2019-09-12

    申请号:US15914598

    申请日:2018-03-07

    Abstract: In one implementation, this disclosure provides a method for executing a partial band rewrite operation comprising identifying a first track of a shingled data band to receive data of a write received at a shingled media storage device and writing a first subset of the received data to a media cache, where the first subset corresponds to the first track of the shingled data band to receive data of the write command. The method also includes writing a remaining subset of the received data to target locations within the shingled data band without updating data on the first track within the shingled data band corresponding to the first subset of the received data.

    Detecting shingled overwrite errors
    8.
    发明授权
    Detecting shingled overwrite errors 有权
    检测覆盖的覆盖错误

    公开(公告)号:US09536563B1

    公开(公告)日:2017-01-03

    申请号:US15044302

    申请日:2016-02-16

    CPC classification number: G11B20/1879 G11B20/10009

    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.

    Abstract translation: 公开了用于检测带状覆盖错误的系统和方法。 当读取带有空白的记录轨道时出现读取错误时,处理器可以确定读取错误是否是由遮盖重写引起的错误。 处理器可以通过例如基于比特错误计数或比特误码率(BER)来确定读取错误是由通过确定读取错误之前的一个或多个扇区的读取信号质量的带状重写引起的,以及比较读取信号质量 达到阈值。 当读取信号质量值低于阈值时,处理器可以确定读取错误是由带状重写引起的。

    Combining selected data from two or more passes to recover a data sector
    9.
    发明授权
    Combining selected data from two or more passes to recover a data sector 有权
    组合来自两个或更多遍的所选数据以恢复数据扇区

    公开(公告)号:US09460750B1

    公开(公告)日:2016-10-04

    申请号:US14865113

    申请日:2015-09-25

    CPC classification number: G11B20/1217 G11B5/02 G11B5/59627 G11B2020/1232

    Abstract: A data sector is read using two or more passes of a read head over a recording medium. Each of the passes corresponds to a different cross-track offset, each of the data sectors being divided into two or more blocks. For each of the blocks, data is selected from one of the passes that read the block with a higher quality than other passes that read the block. The selected data from each of the blocks to is combined to form recovered data of the data sector.

    Abstract translation: 使用读取头在记录介质上的两次或多次通过来读取数据扇区。 每个通道对应于不同的交叉磁道偏移,每个数据扇区被分成两个或更多个块。 对于每个块,从读取块的其中一个通过中读取块的数据从比读取块的其他通过更高的质量中选择数据。 来自每个块的所选数据被组合以形成数据扇区的恢复数据。

    Thermal spot-dependent write method and apparatus for a heat-assisted magnetic storage device

    公开(公告)号:US11450341B1

    公开(公告)日:2022-09-20

    申请号:US17407652

    申请日:2021-08-20

    Inventor: Xiong Liu Quan Li

    Abstract: An apparatus comprises a write pole for writing data to a magnetic recording medium and a near-field transducer (NFT) optically coupled to a laser source and configured to produce a thermal spot on the medium. A laser driver applies laser operation power (Iop) to the laser source. A channel circuit generates symbols having a length of nT, where T is a channel clock rate and n is an integer. The laser driver applies Iop to the laser source and a write driver applies bi-directional write currents to the write pole to record the symbols at a location of the thermal spot on the medium, wherein a duration of applying Iop to the laser source by the laser driver is dependent on a length of the symbols and the effective thermal spot size.

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