This synchronization mechanism insures that the desired output which is presented to the foreground program is in {TAIL ~ fact} based on {HEAD ~ real time data} 
This synchronization mechanism insures that the desired output which is presented to the foreground program is in { TAIL ~ fact } based on { HEAD ~ real time data }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD