Information storage device, write current adjustment method for the information storage device, and write control circuit

A write current adjustment method for an information storage device controlling a steady state value, an overshoot value, or an overshoot width of a write current for writing into a recording medium, the method comprising:

• measuring a Viterbi Metric Margin;
• and
• setting the write current, based on a value of the measured Viterbi Metric Margin, such that a data writing spot is prevented from spreading during writing into the medium and occurrence of side erasure is prevented;
• wherein the measuring measures a value of a lead Viterbi Metric Margin at the beginning of writing into the recording medium, and the setting sets the write current so as to prevent deterioration in signal quality at the beginning of writing, based on the measured value of the lead Viterbi Metric Margin.

A write control circuit controlling a steady state value, an overshoot value, or an overshoot width of a write current for writing into a recording medium, the circuit comprising:

• a Viterbi Metric Margin measurement section to measure a Viterbi Metric Margin;
• and
• a write current setting section to set the write current, based on a value of the Viterbi Metric Margin measured by the Viterbi Metric Margin measurement section, such that a data writing spot is prevented from spreading during writing into the medium and occurrence of side erasure is prevented;
• wherein the Viterbi Metric Margin measurement section further measures a value of a lead Viterbi Metric Margin at the beginning of writing into the recording medium, and the write current setting section sets the write current so as to prevent deterioration in signal quality at the beginning of writing, based on the measured value of the lead Viterbi Metric Margin.