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