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Equalization Adjustment for Data Recovery

IP.com Disclosure Number: IPCOM000099563D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Kerwin, GJ: AUTHOR

Abstract

The figure illustrates a recovery technique which employs an equalization adjustment mechanism in the recording data channel to assist in recovering from soft errors caused by data pulses being non-optimally equalized. Employing a change in equalization in conjunction with a re-read operation as a portion of the Data Recovery Procedure (DRP) enhances the overall effectiveness of the procedure.

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Equalization Adjustment for Data Recovery

       The figure illustrates a recovery technique which employs
an equalization adjustment mechanism in the recording data channel to
assist in recovering from soft errors caused by data pulses being
non-optimally equalized.  Employing a change in equalization in
conjunction with a re-read operation as a portion of the Data
Recovery Procedure (DRP) enhances the overall effectiveness of the
procedure.

      Optimum equalization for a given data record depends to some
extent on the data patterns on the adjacent tracks. Re-reading with
varying equalization offers an increase in the probability of
recovering the data due to a more optimum equalizer value for the
particular adjacent track interference.  Other error-producing
sources that will be compensated for with the use of this DRP step
are misequalization due to different head/disk combinations and
granularity in the equalization bands.

      The technique consists of using a series of incremented and
decremented equalization adjustments while reading the record in
error.  The amplitude of the equalization increment is chosen to
strike a balance between the most effective value from the standpoint
of recovering the data and from the standpoint of minimizing the
impact on the probability of miscorrecting.  Once the increment value
is determined, the optimum position of this operation in the total
data recovery sequence is found.  The process of determining the
re...