An “execution server” manages {HEAD ~ requests} from {TAIL ~ client machines} based on priorities assigned to the requests 
from
An “ execution server ” manages { HEAD ~ requests } from { TAIL ~ client machines } based on priorities assigned to the requests
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH