Browse Prior Art Database

Reassign Technique Utilizing Mapped Defect Information

IP.com Disclosure Number: IPCOM000123211D
Original Publication Date: 1998-Jul-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Ishioka, T: AUTHOR [+4]

Abstract

Disclosed is a method to reassign disk drive's grown defects effectively with minimum defect map complement.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Reassign Technique Utilizing Mapped Defect Information

   Disclosed is a method to reassign disk drive's grown
defects effectively with minimum defect map complement.

   Conventional reassign (grown defect relocation) method
utilizes following conditions (a),b)) to judge the location should be
reassigned or not.
       a) Depth of Error Recovery Procedure (ERP)
          How many retries were done to recover the data.
       b) Kind of effective error recovery method
          What kind of recovery technique was used.  For example,
       Recovered by Offset read, recovered by spare Data sync
       mark read, recovered by dummy sector pulse etc. No need to
       reassign for offset read recovered errors etc.

   But on the other hand, the disk drive defect especially
smear type thermal asperities, which is the predominant MR head disk
drive failure mechanism, grows more rapidly along with genuine defect
locations than other healthy sites on the disk surface.  Past
experience showed 1 Cylinder growth per about 2 Days R/W run across
the drive volume.  To avoid the data integrity defect map problem due
to this rapid defect growth, drive manufacturers have to apply
complement for dispersed defect and compromising with a certain level
of manufacturing yield loss.

   Disclosed method uses following condition c) in addition to
above a) and b).
       c) If the adjacent sector is mapped in the driver
           manufacturing process or lately reassigned during the
           customer operations.

   If condition c) satisfied, the reassign of the sector is
prioritized.  This me...