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Firmware Aided Servo Gain Measurement Method

IP.com Disclosure Number: IPCOM000119066D
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Asano, H: AUTHOR [+3]

Abstract

Disclosed is a method to optimize the servo gain in the actual environment. There is a Hard Disk Drive (HDD) which has a servo gain measurement function in it. Servo gain is measured at the manufacturing line to optimize the flat output throughout the disk surface from the inner side to the outer side of the disk. The servo gain is optimized by changing the servo parameters. The servo gain may vary depending on the actual operation environment and the component characteristics to be changed by time.

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Firmware Aided Servo Gain Measurement Method

      Disclosed is a method to optimize the servo gain in the actual
environment.  There is a Hard Disk Drive (HDD) which has a servo gain
measurement function in it.  Servo gain is measured at the
manufacturing line to optimize the flat output throughout the disk
surface from the inner side to the outer side of the disk.  The servo
gain is optimized  by changing the servo parameters.  The servo gain
may vary depending on  the actual operation environment and the
component characteristics to be  changed by time.

      Servo gain measurement will start when the read error or the
seek error increases more than the pre-determined value which are
periodically measured by Self-Monitoring Analysis and Reporting
Technology (SMART).  If one of those errors exceeds the criteria, HDD
starts to calibrate the servo parameters by measuring the servo
gain.  The initial parameters are kept on the disk for the error
recovery usage in case the updated parameters will cause a worse
condition than  before.

      Also, this calibration will start if the pre-defined error
recovery procedure does not solve the error and the reassign
operation starts in read and write operation.