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Effective Management Method of Spare Area Allocation for Sector and Cylinder Defects

IP.com Disclosure Number: IPCOM000115463D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Matsui, T: AUTHOR [+3]

Abstract

Disclosed is an effective management method for allocating spare areas for defect areas on magnetic disks.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 80% of the total text.

Effective Management Method of Spare Area Allocation for Sector and
Cylinder Defects

      Disclosed is an effective management method for allocating
spare areas for defect areas on magnetic disks.

      In a Hard Disk Drive (HDD) system, read errors can happen if a
defect exists on a track of the disk.

      When such errors happen, an HDD system assigns a spare area is
allocated for writing the data instead of the defect track.

      Defects can occur on servo areas and also data areas.
Conventional HDD systems execute the different spare area assigning
operations for defects in servo areas and for defects in data areas.

      When defects exist in the data area, a spare sector is assigned
for alternating the defect data sector.  When defects exist in a
servo area, a spare cylinder is assigned.  This is because the servo
area's defect influences the seek operation of the system, then the
cylinder having the defect servo area is replaced to the spre
cylinder.  Therefore, if a defect exists on a servo area, the data
tracks including many data sectors relating to the defective servo
area can not be used.  Further, a conventional HDD system must
prepare a spare cylinder region and spare sector region separately,
consequently, the space for the spare region becomes very large.

      This article provides a new method for allocating alternate
regions for defective areas on a disk in a HDD system.

      When a defect exists in a servo region...