News Column

Patent Issued for Extended Address Mark

June 17, 2014

By a News Reporter-Staff News Editor at Journal of Technology -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Ozturk, Mustafa Can (Eden Prairie, MN); Pokharel, Puskal Prassad (Edina, MN); Vikramaditya, Barmeshwar (Eden Prairie, MN), filed on December 19, 2011, was published online on June 3, 2014.

The assignee for this patent, patent number 8743494, is Seagate Technology LLC (Cupertino, CA).

Reporters obtained the following quote from the background information supplied by the inventors: "The present disclosure relates generally to servo sector data used on devices such as hard disk drives (HDDs). The term 'servo sector' (sometimes also referred to as 'embedded servo sectors') describes a pattern of data that is encoded on a device once (e.g., during manufacture) and not re-written thereafter. Servo sectors are relatively small patterns of data arranged at regular intervals along each hard drive tracks comprising variously a preamble field, a digital sync pattern (Servo Address Mark or SAM), digital information for sector and track identification data and analog position burst fields. These tracks are generally configured as concentric circles on magnetic disk(s) of the HDD. While performing tracking and/or data transfer operations, a read/write head detects the servo sectors. A servo demodulator processes the servo sectors, including position burst patterns and sends this information to the servo controller to determine where the read/write head is currently located (e.g., zone, track, data sector) on the disk.

"The writing of the servo sectors can be performed under controlled conditions, e.g., during manufacturing. Nonetheless, factors such as component wear, thermal cycling, disk slip, etc., are known to cause errors in the reading of servo sector data during the life of the drive. The controller may have some provisions for dealing with servo sector errors as part of normal operation. However, if there are large number of such errors, it would impact performance, e.g., increasing seek times and data recovery. This may be of greater concern as areal data densities continue to increase. When areal density increases, the servo sectors may be written in smaller areas, which may also result in an increase in servo sector read errors."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "Various embodiments described herein are generally directed to methods, systems, and apparatus utilizing a conditional extended servo address mark detection. In various embodiments, a method and logic circuit use an extended servo mark word when an error is detected from a servo mark. In another embodiment, a method involves detecting a servo mark associated with a disk drive track during a data access operation. In response to an error in detecting the servo mark, at least one adjacent bit is evaluated together with the servo mark to overcome the error.

"These and other features and aspects of various embodiments may be understood in view of the following detailed discussion and accompanying drawings."

For more information, see this patent: Ozturk, Mustafa Can; Pokharel, Puskal Prassad; Vikramaditya, Barmeshwar. Extended Address Mark. U.S. Patent Number 8743494, filed December 19, 2011, and published online on June 3, 2014. Patent URL:

Keywords for this news article include: Seagate Technology LLC.

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Source: Journal of Technology

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