In some cases, {HEAD ~ multiple computer systems} may be connected, {TAIL ~ each} residing at a node of a network 
In some cases , { HEAD ~ multiple computer systems } may be connected , { TAIL ~ each } residing at a node of a network
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH