Browse Prior Art Database

Stiction Recovery Using Head Load/Unload Detector

IP.com Disclosure Number: IPCOM000123446D
Original Publication Date: 1998-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Ono, H: AUTHOR [+2]

Abstract

Disclosed is an error recovery procedure by sensing head load/unload situation electrically when the spindle motor does not start at the start up operation of hard disk drive. Recent HDD employs head slider load/unload function not to park the heads on the disk surfaces at rest as in the figure 1. The load/unload function has a ramp mechanism to slip the heads on. Applying a pair of electrical poles on the actuator and the outer crash stop or the slider ramp, the actuator controller can detect if the head is parking on the disk or not. If the poles do not get contact, and the spindle does not rotate, the actuator controller judges the head sticks on the disk. Then the controller starts recovery from the stiction. But if no, the controller does not initiate the stiction recovery routine.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Stiction Recovery Using Head Load/Unload Detector

   Disclosed is an error recovery procedure by sensing head
load/unload situation electrically when the spindle motor does not
start at the start up operation of hard disk drive.  Recent HDD
employs head slider load/unload function not to park the heads on the
disk surfaces at rest as in the figure 1.  The load/unload function
has a ramp mechanism to slip the heads on.  Applying a pair of
electrical poles on the actuator and the outer crash stop or the
slider ramp, the actuator controller can detect if the head is
parking on the disk or not.  If the poles do not get contact, and the
spindle does not rotate, the actuator controller judges the head
sticks on the disk.  Then the controller starts  recovery from the
stiction.  But if no, the controller does not initiate the stiction
recovery routine.  This function allows the controller working on
adequate recovery process without waste of power on time.

   First, the actuator controller pushes the actuator to
outer by inducing the current to the voice coil motor.  If the poles
are electrically shorted, then the controller judges the actuator is
under the unload condition.  In the other case, the poles are open
since t e heads are loaded on the disks.  The figure 2 shows an
example of load/unload detector circuit.  The crash stop is directly
connected to the ground.  The actuator has contact point opposite to
the crash stop.  The point is conductive and makes th...