{TAIL ~ The barrier region} allows {HEAD ~ the I/O driver} to be designed to primarily meet I/O requirements 
{ TAIL ~ The barrier region } allows { HEAD ~ the I / O driver } to be designed to primarily meet I / O requirements
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH