Browse Prior Art Database

Scrub Zone for Disk Drive Using Load/Unload

IP.com Disclosure Number: IPCOM000117954D
Original Publication Date: 1996-Jul-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 114K

Publishing Venue

IBM

Related People

Ottesen, HH: AUTHOR [+2]

Abstract

Disclosed is one solution to avoid an excessive buildup of debris on head sliders used in a disk drive employing load/unload.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Scrub Zone for Disk Drive Using Load/Unload

      Disclosed is one solution to avoid an excessive buildup of
debris on head sliders used in a disk drive employing load/unload.

      During normal disk drive operation, the recording head slider
can become contaminated with debris.  The debris attaching itself to
the slider can originate from intermittent slider/disk surface
contact, outgassed materials, or other foreign materials present
inside of the drive.  In some cases, the debris may be thick enough
to contact the disk surface during normal flying.  Excessive debris
on the air bearing surfaces of the sliders decreases the aerodynamic
lift of the slider and reduces the flyheight below acceptable levels.
A disk drive normally parks the heads in a landing zone when the
drive is powered off.  Experimental verifications show that periodic
starting and stopping with head sliders in contact with the landing
zone keeps the air bearing surfaces of the sliders of much of the
debris picked up while flying.

      In the quest for higher magnetic recording densities, the
head-to-disk spacing must be reduced.  Commensurate with lower flying
heights, the disk surface must be very smooth.  Very smooth disk
surfaces preclude a head slider parked in the landing zone from
starting due to stiction.  Load/unload of the head sliders has been
proposed as a means to use very smooth disks, like glass disks, in a
disk drive.  Before a drive is powered off, the head sliders are
unloaded from the disks.  A ramp-type device has been proposed for
unloading and loading of the sliders onto the disks.

      The problem with a disk drive using slider load/unload is that
without periodic starting and stopping on the disk surface, the
debris, as mentioned above, can accumulate in thickness until it is
as thick as  the flyheight.  Operating in this mode will lead to
adhesive wear and may  eventually result in a catastrophical head
crash.

      The nonobvious use of a scrub zone in a load/unload drive is
introduced so that debris can be periodically removed from the air
bearing surfaces of the sliders in the drive.  The scrub zone is an
annular area that may have a coarser surface texture than the
remaining recording surface of the disk.  The scrub zone is located
in such a way on the disk that it will not detract from the data
capacity of the drive.  Two different methods, illustrated in the
Figure, can achieve this:
  1.  If an Outer Diameter (OD) load/unload ramp 12 is used, the
scrub
       zone 14 can be located at the very OD of each disk surface 10.
       To perform a periodic scrub, the ramp 12 is temporarily
rotated
       (moved) out of the way so that the sliders can get access to
the
       scrub zone 14 which is the annular region immediately beneath
the
       ramp 12.  The scrubbing...