a registration unit that, when receiving a print request from any one of the plurality of host computers, registers host information indicative of {TAIL ~ the host computer} as {HEAD ~ a source} of the request so that an order of print requests can be identified 
a registration unit that , when receiving a print request from any one of the plurality of host computers , registers host information indicative of { TAIL ~ the host computer } as { HEAD ~ a source } of the request so that an order of print requests can be identified
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH