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The method to skip a defective track by scannig Primary Defect Map

IP.com Disclosure Number: IPCOM000015890D
Original Publication Date: 2002-Apr-04
Included in the Prior Art Database: 2003-Jun-21
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Abstract

Terminology Defective Track : A data track which has no available sector or has a servo stability problem PDM : Primary Defect Map Disclosed is a method to skip a defective track of Hard Disk Drive(HDD) by scanning PDM, and this never make physial boundary of data zone move by defectvie tracks. Normally, a defective track is registered in the alternative cylinder table or track table to avoid seeking to it. Both merit and demerit about this method is given below. [Merit]

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The method to skip a defective track by scannig Primary Defect Map

Terminology Defective Track :A data track which has no available sector or has a servo stability problem PDM : Primary Defect Map

Disclosed is a method to skip a defective track of Hard Disk Drive(HDD) by scanning PDM, and this never make physial boundary of data zone move by defectvie tracks.

Normally, a defective track is registered in the alternative cylinder table or track table to avoid seeking to it. Both merit and demerit about this method is given below.

[Merit]

- Never set a defective track as seeking target because it is skipped by scanning alternative cylinder table/track table

[Demerit]

- The physical location of boundary (Data Zone, Data Band) is affected by defective tracks - One defective track of a head affects the tracks of other heads if the method of alternative cylinder table is used - The table size of the alternative track table comes to be huge because it is necessary to define the table by head

There is a method to overcome the demerit above by registering all sectors of a defective track to PDM.And this method has different merit and demerit.

[Merit]

- The physical location of boundary (Data Zone, Data Band) is never affected by defective tracks - It is efficient because only the sectors of defective track are registered to PDM - It is unnecessary to have such a alternative cylinder/track table

[Demerit]

- Set defective track as seeking target once before detect it is bad...