Western Digital Technologies, Inc.

Mao Nishiyama

Zarko Popov

Hitoshi Yoshida

Xing Huo

Bernd Lamberts

Wayne Howard Vinson

Masato Taniguchi

Victor Ramirez

Hiroyasu Tanabe

A Data Storage Device (DSD) includes a disk for storing user data in tracks including sectors. Adjacent Track Interference (ATI) values are determined for annular locations along a guard band location designated to not store user data and to separate a first region of tracks from a second region of tracks. Based on the ATI values determined for the annular locations, guard band sectors are assigned from one or more adjacent tracks of the second region corresponding to one or more locations where the one or more adjacent tracks are deemed more susceptible to data corruption based on the determined ATI values. The assigned guard band sectors form part of the guard band. According to one aspect, the ATI values are determined based on at least one Magnetic Recording Metric (MRM) and a track pitch.

Guard band assignment for shingled magnetic recording

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: maintain a refresh monitor for a refresh zone of one of the one or more disks, wherein the refresh zone comprises at least one data sector; update the refresh monitor in response to a write operation being performed in a track different than a track containing the refresh zone; update the refresh monitor at predefined time intervals based on a temperature of the one of the one or more disks or of the data storage device; and control a refresh operation of the refresh zone using the refresh monitor.

Data storage device with combined track interference and thermal decay refresh monitor

Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator assembly comprising one or more disk heads; and one or more processing devices, configured to detect a plurality of areas with a coercivity lower than a threshold on the one or more disks; map out one or more sectors in each of the plurality of lower coercivity areas on the one or more disks; write data to, or read data from, the one or more disks, based at least in part on mapping out the one or more sectors in each of the plurality of lower coercivity areas. In some embodiments, the writing or reading data comprises writing data to, or reading data from, one or more sectors of the one or more disks that are not mapped out.

Sector mapout of low coercivity media for enhancing aerial density

The present disclosure is directed to a data storage device that includes a refresh monitor based on a learning based feedback control. The refresh monitor is used to control refresh operations to account for effects of writes to media, e.g., adjacent track interference (ATI). Read operations are analyzed to derive damage information usable to update one or more probability distributions, upon which the learning is updated or reinforced and carried forward. In one embodiments, the data storage device includes control circuitry configured to maintain a refresh monitor based on a learning system, analyze a read operation with the refresh monitor; adjust the refresh monitor by updating the one or more probability distributions based on the analyzed read operation; and execute a refresh operation to refresh data based on the adjusted refresh monitor.

Growing community of inventors

Kanagawa, Japan

Mao Nishiyama