Ensuring alignment of {TAIL ~ the data} in {HEAD ~ time} for all the subsystems is problematic 
Ensuring alignment of { TAIL ~ the data } in { HEAD ~ time } for all the subsystems is problematic
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH