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Erasure Error Correction Code Correction for Hard Disk Drive Application

IP.com Disclosure Number: IPCOM000117443D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Kigami, Y: AUTHOR [+4]

Abstract

This article describes about a Hard Disk Drive which has Error Correction Code (ECC) and correction method which determines the error location with read write channel signals.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Erasure Error Correction Code Correction for Hard Disk Drive Application

      This article describes about a Hard Disk Drive which has
Error Correction Code (ECC) and correction method which determines
the error location with read write channel signals.

      If there is a large missing bits location and/or large extra
bits location which can not be corrected ON THE FLY, Micro code goes
into the Error Recovery Procedure (ERP) mode and does some special
read process called Erasure correction.

      The Figure shows the one of the implementation of this
algorithm.  If there is a large missing bits, Channel pulse detector
outputting Peak Detection Read Signal (PDRD) has no signal region as
shown (2) in Fig. 1.  Hard Disk Controller (HDC) is counting the low
period and if it exceeds 2 bytes length which can not exist in the
normal Run length, HDC enables the Erasure detection bits and save
the location onto the memory as shown (3) in Fig. 1.  Micro code can
apply Error Correction at the erasure area as (4), which may have a
data error called Erasure correction.

      The benefit of this method is minimizing the ECC overhead about
1/2 compared to conventional correction methods.