a beam supplying unit for supplying {HEAD ~ an incident laser beam} including {TAIL ~ data} read from a plurality of tracks on a holographic medium 
a beam supplying unit for supplying { HEAD ~ an incident laser beam } including { TAIL ~ data } read from a plurality of tracks on a holographic medium
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH