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Increasing Head/Disk Interface Life of a Disk Drive by Introducing Small Radial Head Movement During Start/Stop Operations

IP.com Disclosure Number: IPCOM000110319D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 99K

Publishing Venue

IBM

Related People

Koka, VR: AUTHOR [+2]

Abstract

Typically, the magnetic head in a rigid disk drive slides at a fixed radius on the disk and the interface life is limited to how much sliding wear the disk can withstand before it delaminates or deteriorates. The wear life can be significantly improved by small random radial motion of the head while it is in sliding contact with the disk.

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Increasing Head/Disk Interface Life of a Disk Drive by Introducing Small Radial Head Movement During Start/Stop Operations

       Typically, the magnetic head in a rigid disk drive slides
at a fixed radius on the disk and the interface life is limited to
how much sliding wear the disk can withstand before it delaminates or
deteriorates.  The wear life can be significantly improved by small
random radial motion of the head while it is in sliding contact with
the disk.

      A typical head in a rigid disk drive consists of two rails
which slide and fly on a disk, and is able to rotate about a pivot
which can move in a vertical direction.  Since the head and disk
surfaces have some roughness, at any instant when the head is sliding
on the disk, it is supported by the high peaks and ridges of the disk
under the rails of the head.  These points of contact establish a
contact plane as illustrated in the figure.  This plane is a function
of the dimensions and distribution of high peaks/ridges and the
waviness under both rails of the head.  The contact plane is
continuously changing as the disk surface passes under the rails
because the dimensions and distributions of peaks/ridges and waviness
are not the same in a circumferential band of the disk.

      If the head is made to slide at a fixed radius and not allowed
to move radially, then the contact plane remains the same each time
when the same angular sector of the disk passes under the rails.
This implies that the head repeatedly slides on the same set of high
peaks/ridges on the disk.  Therefore, the stresses from head load and
sliding friction are concentrated on the same contact points.  We can
expect the contact plane to change only when there is significant
wear of the high peaks/ridges, and when there is wear debris or
external particles introduced under the rails.

      If the hea...