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