Browse Prior Art Database

Data Re-Write Procedure for Magnetic Recording Device

IP.com Disclosure Number: IPCOM000122158D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Kurachi, K: AUTHOR [+3]

Abstract

Disclosed is a data re-write procedure in an error recovery process of hard disk drives. The error recovery process consists of many operations to read the data correctly when a symbol error occurred in the first read operation. When a symbol error occurred in data read operation, one method to recover the error is to read the data again or intentionally move the Read/Write head to off-track positions. The off-track means the shift of the Read/Write gap of the head from an ideal track center (i.e., on-track).

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This is the abbreviated version, containing approximately 76% of the total text.

Data Re-Write Procedure for Magnetic Recording Device

      Disclosed is a data re-write procedure in an error
recovery process of hard disk drives.  The error recovery process
consists of many operations to read the data correctly when a symbol
error occurred in the first read operation.  When a symbol error
occurred in data read operation, one method to recover the error is
to read the data again or intentionally move the Read/Write head to
off-track positions.  The off-track means the shift of the Read/Write
gap of the head from an ideal track center (i.e., on-track).

      If the symbol error is recovered at an off-track position, it
probably seems that the data was written at the off-track position
because of track misregistration (TMR) in the write operation.  In
this situation, therefore, the data should be re-written just on the
center of the data track in a small TMR condition after successful
data read at an off-track position.  Otherwise, when the same data is
accessed again, the drive system has to perform the same error
recovery process (i.e., off-track read) again.  Thus, the data
re-write operation can reduce the number of READ-RETRY because of
data off-track write.  The figure shows an error recovery process by
the data re-write procedure.

      The advantages of the data re-write procedure are as follows:
1)   If the data re-write is applied to a specific data track, the
same symbol error due to OFF-TRACK WRITE does not occur in the n...