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Micro defect entry method in defect mapping at hard disk drive test

IP.com Disclosure Number: IPCOM000014735D
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2003-Jun-20

Publishing Venue

IBM

Abstract

Disclosed is a defect sector mapping method for hard disk drive to skip the particular defect sites described in below at manufacturing test. Contemporary hard disk drive has the function to alternate defect sectors. The defects are identified by referring to the bit error length and the depth. However, the data at the sites with a very small defect (called micro defect) can be easily recovered by error correction code (ECC) algorism so that they have not been alternated so far. But micro defects lead to uncorrectable read errors on modern disks with very smooth surface. The micro defects have the following characteristics.