Browse Prior Art Database

Error Correction Code for Servo ID

IP.com Disclosure Number: IPCOM000116095D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Kisaka, M: AUTHOR

Abstract

Servo information to identify position of a head in a hard disk drive has track ID portion usually coded in gray code. Incorrect reading of this ID would cause illegal read operation if No-ID type format is used that uses the ID for read operation. This invention describes the method that puts Error Correction Code (ECC) for track ID in the user data area.

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

Error Correction Code for Servo ID

      Servo information to identify position of a head in a hard disk
drive has track ID portion usually coded in gray code.  Incorrect
reading of this ID would cause illegal read operation if No-ID type
format is used that uses the ID for read operation.  This invention
describes the method that puts Error Correction Code (ECC) for track
ID in the user data area.

      The track format currently used is in Fig. 1.  The user data is
read after checking the track ID information.  Therefore, reliability
of the information is important.  One method to increase reliability
is adding error checking code after the ID.  However, the frequency
of the ID is about 5 MHz, so adding the additional information
consumes much area.

      To reduce the required data area, Fig. 2 format can be used.
In Fig. 2 ECC is added in user data area whose frequency is more than
20 MHz.  Therefore, less data area is consumed.