When a print request is received from one of a plurality of hosts, {HEAD ~ host information} indicative of {TAIL ~ the host} is registered so that an order of print requests can be identified 
indicative of
When a print request is received from one of a plurality of hosts , { HEAD ~ host information } indicative of { TAIL ~ the host } is registered so that an order of print requests can be identified
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH