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Reliable Seek Completion Monitoring the Back Side Head Signal

IP.com Disclosure Number: IPCOM000114312D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Kibashi, A: AUTHOR [+3]

Abstract

Disclosed is a method to improve the reliability of head positioning at completion of SEEK operation of Hard Disk Drive which uses sector servo control with staggered servo pattern.

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This is the abbreviated version, containing approximately 63% of the total text.

Reliable Seek Completion Monitoring the Back Side Head Signal

      Disclosed is a method to improve the reliability of head
positioning at completion of SEEK operation of Hard Disk Drive which
uses sector servo control with staggered servo pattern.

      It is achieved by verifying the track following stability
checking servo information of back side head before completion of
seek operation.

      Most of the current hard disk drives which use sector servo
control method use servo information of target head only to perform
seek operation.  This means that seek operation is performed without
any position error information in between a sector and the next
sector.  Therefore, if the head is oscillating with a half or integer
multiple of servo sampling frequency, the seek operation will be
completed and the read or write operation will be started without
knowing the head oscillation.

      Fig. 1 shows this phenomena.  Though the head is oscillating,
it is observed as if the head were settled enough since the position
error is almost zero at sampling point.

      Though there exists a servo control method that always uses
servo information of both target and back side head during seek
operation to double servo sampling frequency, this method results in
cost increase because it requires higher speed processor.

      As shown in Fig. 2, the new method uses servo information on
not only target head, but also the back side head to verify stability
o...