Browse Prior Art Database

HDD GMR Head Reset History in Re-assign Map Area

IP.com Disclosure Number: IPCOM000123069D
Original Publication Date: 1998-May-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Related People

Suzuki, H: AUTHOR [+3]

Abstract

Disclosed is a method to memorize /update GMR (giant magnetoresistive) head reset history (reset voltage/current, times) automatically, during ERP (error recovery procedure) running. In case ERP steps continue to fail read /write operation, head performance degradation (poorer error rate by less amplitude, other) is possible reason. If head is doubt, GMR reset is tried to restore original performance. And then, ERP retry (full or subset) starts.

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HDD GMR Head Reset History in Re-assign Map Area

   Disclosed is a method to memorize /update GMR (giant
magnetoresistive) head reset history (reset voltage/current, times)
automatically, during ERP (error recovery procedure) running.  In
case ERP steps continue to fail read /write operation, head
performance degradation (poorer error rate by less amplitude, other)
is possible reason.  If head is doubt, GMR reset is tried to restore
original performance.  And then, ERP retry (full or subset) starts.

   To memorize tried reset condition by head, certain memory
area on the disk /RAM (random access memory) is necessary.  If such
area is combined with re-assign map area, and if ERP retry after GMR
reset is specified as re-assign (defect re-allocation) steps, reset
history can be updated automatically.  If history is changed by reset
on RAM, update on disk is performed when re-assign is occurred.

   If history area is prepared in different disk /RAM area
from re-assign's, both history and re-assign map should be updated,
at the same time.

   Besides history example (voltage/current, times), head
performance before/after reset (error rate, MSE, amplitude) can be
added.