Browse Prior Art Database

Servo Positioning for Variable Disk RPM

IP.com Disclosure Number: IPCOM000117009D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Kagami, N: AUTHOR [+4]

Abstract

Disclosed is a method for servo positioning of Magnetic head of Disk drive apparatus on variable Disk rotation speed for Error recovery procedure of read error caused by thermal asperity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 85% of the total text.

Servo Positioning for Variable Disk RPM

      Disclosed is a method for servo positioning of Magnetic head of
Disk drive apparatus on variable Disk rotation speed for Error
recovery procedure of read error caused by thermal asperity.

      A phenomenon called thermal asperity arises when a Magnetic
head which contains an MR stripe hits a projection on the disk
surface.  Thermal asperity makes illegal read signals change the
Magnetic head which result in data error.

      The Figure shows a Block diagram of the method associated with
base clock for Disk Drive apparatus.  There are three base clocks.
They are for:
  1.  spindle rotation speed control
  2.  servo pattern read logic
  3.  data transfer frequency control.

      Base clock controller (13) can generate variable frequency
clock.  Servo pattern base clock logic (9) make base clock (14) for
Servo pattern read logic (8) form base clock supplied by base clock
controller (13).  Spindle control base clock logic (12) make base
clock (15) for spindle controller from base clock supplied by base
clock controller (13).  Frequency of spindle control base clock is
always in proportion to that of servo pattern read logic.

      Spindle rotation speed can be changed by changing the base
clock that the base clock controller generates.

      Servo pattern can be read at variable spindle speeds and servo
position is done by using servo pattern information.

      With this function, Disk d...