In one embodiment, the scan logic 20 deduces this distance yet to be covered from {HEAD ~ the comparison} of the output of the analog to digital converter 44 with {TAIL ~ the map} of plot A, and outputs a media position error signal 
In one embodiment , the scan logic 20 deduces this distance yet to be covered from { HEAD ~ the comparison } of the output of the analog to digital converter 44 with { TAIL ~ the map } of plot A , and outputs a media position error signal
OTH OTH OTH OTH OTH OTH OTH 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 REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH