The relationship between at {TAIL ~ the determined PcO value} and SmO is subjected to linear approximation, and the compensated write power {HEAD ~ PthO} that provides a modulation of zero, that is, an evaluated value SmO of zero, is determined 
The relationship between at { TAIL ~ the determined PcO value } and SmO is subjected to linear approximation , and the compensated write power { HEAD ~ PthO } that provides a modulation of zero , that is , an evaluated value SmO of zero , is determined
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH