Seagate Technology Incorporated

Other

Aik Chuan Lim

Xiong Liu

Yong Peng Chng

Steven TianChye Cheok

Kay Hee Tang

Kevin Arthur Gomez

Qiang Bi

ChoonKiat Lim

UttHeng Kan

Choon Kiat Lim

Edmun ChianSong Seng

Wei Loon Ng

YongPeng Chng

WeiLoon Ng

Utt Heng Kan

KayHee Tang

Patrick Tai Heng Wong

Edmun Chian Song Seng

Steven Tian Chye Cheok

Jimmy Tze Ming Pang

Jeffrey Soon Beng Sim

Ying Ee Yip

Chew Boon Toh

In one embodiment of the present invention, systems and methods are provided through which the capacity of a defect buffer in a microcontroller of a mass storage device is determined without regard for the quantity of defects on a recording medium. The capacity of the defect buffer is determined in varying examples, based on the amount of available buffer space and/or the application of the storage device. In one embodiment, the capacity of the defect buffer is less than the quantity of defects on the recording medium, wherein entries in a defect table on the recording medium are swapped in and out of the defect buffer as needed, such as using a most-recently-used scheme. In another embodiment of the present invention, systems and methods are provided through which the defect table is partitioned into a plurality of segments that are physically distributed throughout the recording medium.

System and method for adaptive storage and caching of a defect table

The present invention provides a method of describing defects that requires less memory space than conventional methods. Entries of a first defect table are sorted according to the type of track layout, or zones. They are then grouped into clusters. Each cluster is characterized by a set of new parameters, including a starting sector, a scratch parameter, a span parameter, and an angle parameter. The new parameters are stored in a second table, replacing the corresponding entries in the first table. In this manner, a single entry in the second table replaces one or more entries in the first table with one entry in the first table.

Pattern-based defect description method

An apparatus and method of predicting functional capability of a data storage device having a plurality of information tracks, comprising performing a DC erase on three adjacent information tracks, writing a predetermined bit pattern on a middle track of the three adjacent information tracks, providing a first signal from the bit pattern to a variable gain amplifier to generate a first value of the variable gain amplifier, performing DC erases on the information tracks adjacent the middle track, reading the bit pattern from the middle track to provide a second signal to the variable gain amplifier to generate a second value of the variable gain amplifier, and operating on the first and second values of the variable gain amplifier to provide a track mis-registration value for use with a predetermined threshold value to determine the functional capability of the data storage device.

Track mis-registration measurement for a disc drive

A method of, apparatus for, and means for controlling pitch of a servowritten track on a disc in a disc drive are disclosed. The disc drive has a head for traversing over a surface of the disc. The head has a read element and a write element separated by a head element offset &Dgr;. A servowriting controller operably connected to the disc drive creates a track k by writing servo information on the disc. The servowriting controller then calculates the head element offset &Dgr; at the track k, &lsqb;&Dgr; (k)&rsqb; and determines a skew angle &thgr; at the track k, &lsqb;&thgr;(k)&rsqb;. The servowriting controller adjusts a track pitch correction factor based on the &Dgr; (K) and the &thgr;(k) such that the track pitch correction factor is utilized to servowrite a next track.

Track pitch control using head offset measurement for self-servowriting tracks in a disc drive

A method of and apparatus for generating a reader-to-writer offset for a head positioned over a track on a disc in a disc drive having a plurality of tracks is disclosed. A reader and a writer are mounted on the head in a non-overlapping manner with a gap between the reader and the writer, which is known as the reader-to-writer offset. A disc drive controller is operably connected to the reader and the writer. The disc drive controller determines the reader-to-writer offset of the head for each track by computing the difference between a first head position x1 and a second head position x2. The first head position x1 is an optimal head position for writing information on the track and the second head position x2 is a midpoint of an off-track capability (OTC) of the head. The OTC is a portion of a track pitch over which the reader is expected to read information that is free of an incorrigible bit error such that the writer-to-reader track misregistration (TMR) is minimized as the head is radially displaced the reader-to-writer offset to read information written on the track or to write information on the track.

Optimal reader-to-writer offset measurement of a head in a disc drive for reduced track misregistration

A method of storing values that involves splitting each value into a n-bit value and an overflow value, and storing, in a main table, the n-bit values in order of increasing magnitude of the values. For each overflow value, the position of the smallest n-bit value is stored in an overflow table. To retrieve a value, the position of the corresponding n-bit value is compared to the positions stored in the overflow value to determine the overflow value of the n-bit value. The actual value is then obtained from the n-bit value and its overflow value.

Method of overflow-based defect management representation

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Singapore, Singapore

Aik Chuan Lim