On the other hand, when {HEAD ~ the determination} is made by {TAIL ~ the ECC check} at Step 509 that “an error exists” 
is made by
On the other hand , when { HEAD ~ the determination } is made by { TAIL ~ the ECC check } at Step 509 that “ an error exists ”
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH