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Read Bias Current Increment for Data Recovery

IP.com Disclosure Number: IPCOM000099557D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Kerwin, GJ: AUTHOR [+2]

Abstract

Employing an increase in the magneto-resistive head element read bias current in conjunction with a reread operation as a portion of a data recovery procedure (DRP) complements other DRP steps to enable the procedure to be more effective and efficient. This step increases the signal-to-noise during a DRP-read operation by increasing the signal proportionally to the increase in bias current. This results in a higher probability of a successful read.

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Read Bias Current Increment for Data Recovery

       Employing an increase in the magneto-resistive head
element read bias current in conjunction with a reread operation as a
portion of a data recovery procedure (DRP) complements other DRP
steps to enable the procedure to be more effective and efficient.
This step increases the signal-to-noise during a DRP-read operation
by increasing the signal proportionally to the increase in bias
current.  This results in a higher probability of a successful read.

      Table 1 and the flow chart in the figure depict the steps of
the total DRP including the "Reread With Increased Read Bias Current"
step.

      Upon detection of an error through a miscompare of the freshly
calculated error checking and correctrion (ECC) value to that written
with the data, the DRP is initiated. Steps 1 through 4 are performed
prior to the "bias current modification" step.  If the ECC values
continue to miscompare, the programmable-read-bias current value is
raised to recover the data.  The next step shows the
read-bias-current further increased.  If recovery has not happened,
the procedure is continued until all steps have been taken.  Only
after the entire procedure has been executed is the error termed and
reported as a hard error.