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Browse Prior Art Database

Dynamic Control of Write Cache and Defect Reallocation

IP.com Disclosure Number: IPCOM000118264D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Hashimoto, M: AUTHOR [+3]

Abstract

Disclosed is an algorithm which minimizes the ratio of sector reallocation caused by improper installation or improper physical mounting of a Hard Disk Drive.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 78% of the total text.

Dynamic Control of Write Cache and Defect Reallocation

      Disclosed is an algorithm which minimizes the ratio of sector
reallocation caused by improper installation or improper physical
mounting of a Hard Disk Drive.

      The algorithm reduces the possibility that the drive runs out
of its spare sectors because it eliminates the reallocation due to
improper installation of the drive.

      This algorithm is composed of the following three
routines.  These routines are embedded in the sector reallocation
microcode.
         (1) Servo analysis routine

      Servo analysis routine measures variance of Position Error
Signal to see the stability.  It also checks discontinuous Position
Error Signal to detect defective Servo signal.  This measurement is
used for judging if the reallocation is truly necessary.
      analyze Position Error Signal of 1 disk revolution
      IF ( servo stability exceeds a criteria ) {
      IF ( discontinuous Position Error Signal is detected )
      FLAG = FALSE ; Since this is caused by
      ; improper installation
      ELSE
      FLAG = TRUE
      } ELSE {
      FLAG = FALSE
      }
      (2) Reallocation routine
      reallocate a sector
      invoke Servo analysis routine (1) ; This routine sets FLAG
      IF ( FLAG == TRUE ) {
      record Reallocation_Cancel mark in reallocation table
      ; Cancellation will be
      ; done...