Browse Prior Art Database

Adaptable Structure for Clipping Damaged Heads out of Drive

IP.com Disclosure Number: IPCOM000118270D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Andoh, H: AUTHOR [+4]

Abstract

Disclosed is a method to make a Hard Disk Drive (HDD) operate as a clipped capacity model, even if damaged heads are included. It happens by saving the head table that has the information (on all heads). The HDD loads this table on Power On Reset (POR).

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

Adaptable Structure for Clipping Damaged Heads out of Drive

      Disclosed is a method to make a Hard Disk Drive (HDD) operate
as a clipped capacity model, even if damaged heads are included.  It
happens by saving the head table that has the information (on all
heads).  The HDD loads this table on Power On Reset (POR).

      Until now, Manufacturing (MFG) replaced the damaged heads with
good heads, because the assumption was that all heads work well.  By
saving the heads table that has the damage information on all of its
heads, and loading the heads on POR, the HDD can operate just like a
clipped capacity model.

      Previously, MFG saved the head table on all good heads, and HDD
loaded the head table on POR by a head that can be servo locked
first.  After loading the head table, HDD always referred to the
table and chose the physical head to Read/Write.  As shown in the
Figure, if HDD wants to Read/Write with logical head 3, HDD will know
to output/input signal to/from the physical head 4 by referring to
the head table.