Performance based write current optimization process

A method of optimizing write current in data storage system, comprising:

• selecting a write current level;
• writing data on a first data track in the storage system at the write current level;
• writing adjacent track interference on a second data track which is adjacent to the first data track;
• reading the data from the first data track;
• measuring off-track error rate in the data read from the first data track;
• repeating the steps of reading and measuring to obtain a plurality of error rates at the selected write current level;
• changing the selected write current level;
• repeating the steps of writing data, writing adjacent track interference, reading, measuring, and repeating the steps of reading and measuring;
• and
• determining an optimum write current level as a function of the measured rates.

A method of optimizing write current in a data storage system, comprising:

• selecting a write current level;
• writing background interference on a first data track in the storage system;
• writing data on the first data track at the selected write current level;
• writing adjacent track interference on a second data track that is adjacent to the first data track;
• reading the data from the first data track;
• determining an error rate in the data read from the first data track;
• repeating the steps of reading and determining an error rate to obtain a plurality of error rates at the selected write current level;
• selecting a lowest error rate from the plurality of error rates at the selected write current level;
• logging the lowest logged error rate;
• changing the selected write current level;
• repeating the steps of writing background interference, writing data, writing adjacent track interference, reading, determining an error rate, repeating to obtain a plurality of error rates, selecting and logging;
• and
• determining an optimum write current level as a function of the logged error rates.

A method of optimizing write current in a data storage system, comprising:

• selecting a write current level;
• writing background interference on a first data track in the storage system;
• writing data on the first track at the selected write current level;
• writing adjacent track interference on a second data track that is adjacent to the first data track;
• reading the data from the first data track;
• determining an error rate in the data read from the first data track;
• logging the error rate;
• changing the selected write current level;
• repeating the steps of writing background interference, writing data, writing adjacent track interference, reading, determining an error rate, logging and changing to obtain more than two logged error rates;
• determining a minimum logged error rate;
• fitting a curve to at least three of the logged error rates, wherein one of the three logged error rates includes the minimum logged error rate;
• and
• selecting an optimum write current level as a write current level that corresponds to a lowest point on the curve.

A method of optimizing write current in a data storage system, comprising:

• selecting a write current level;
• writing background interference on a first data track in the storage system;
• writing data on the first data track at the selected write current level;
• writing adjacent track interference on a second data track that is adjacent to the first data track;
• reading the data from the first data track;
• determining an error rate in the data read from the first data track;
• logging the error rate;
• changing the selected write current level;
• repeating the steps of writing background interference, writing data, writing adjacent track interference, reading, determining an error rate, logging and changing;
• determining a lowest logged error rate, the lowest logged error rate having a corresponding write current level;
• determining a next lowest logged error rate, the next lowest logged error rate having a corresponding write current level;
• selecting an optimum write current level as the write current level corresponding to the lowest logged error rate if a difference between the lowest and next lowest logged error rates is greater than a selected factor;
• and
• selecting the optimum write current level as a level between the write current levels corresponding to the lowest and next lowest logged error rates if the difference is less than the selected factor.