and indicate the position directed by the contents of the IMA counter to represent {HEAD ~ the position} of {TAIL ~ the present cursor} 
of
and indicate the position directed by the contents of the IMA counter to represent { HEAD ~ the position } of { TAIL ~ the present cursor }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL