Browse Prior Art Database

Adaptive Head Selection for Hard Disk Drive Application

IP.com Disclosure Number: IPCOM000116601D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Aoki, Y: AUTHOR [+3]

Abstract

Disclosed is a Hard Disk Drive which has extra magnetic heads for target capacity. With higher recording density, production yield depends on read-write-performance of magnetic heads. By using selected read-write-performance heads, in other words, disabling poor or marginal read-write-performance heads, production yield is improved.

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

Adaptive Head Selection for Hard Disk Drive Application

      Disclosed is a Hard Disk Drive which has extra magnetic heads
for target capacity.  With higher recording density, production yield
depends on read-write-performance of magnetic heads.  By using
selected read-write-performance heads, in other words, disabling poor
or marginal read-write-performance heads, production yield is
improved.

The following describes about four basic concepts of this article:
  1.  Having one extra magnetic head for target capacity of Hard Disk
       Drive makes it possible to select good read-write-performance
       heads.  For example, using five selected heads among six
default
       mounted heads to achieve 2G byte Hard Disk Drive.
  2.  To disable a worst magnetic head, measure
read-write-performance
       in manufacturing test
  3.  Using physical-logical head number conversion table in EEPROM,
       any head can be disabled even it is Power-On-Reset default
head.
       For example,
             Phisical Head 0                 Logical Head 0
             Phisical Head 1                 Logical Head 1
             Phisical Head 2  <- Skipped     Not Used
             Phisical Head 3                 Logical Head 2
             Phisical Head 4                 Logical Head 3
             Phisic...