The evaluated value Smn=Mm× is calculated from {HEAD ~ a plurality} of different write power compensated values Pcn , the write power Pwm, and {TAIL ~ the modulation} Mm 
The evaluated value Smn = Mm× is calculated from { HEAD ~ a plurality } of different write power compensated values Pcn , the write power Pwm , and { TAIL ~ the modulation } Mm
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH