Preferably, the system includes {HEAD ~ a transaction interface} associated with {TAIL ~ the control system} for carrying out a current transaction 
Preferably , the system includes { HEAD ~ a transaction interface } associated with { TAIL ~ the control system } for carrying out a current transaction
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH