{HEAD ~ Scanning engine} 310 sends {TAIL ~ request} 315 to direct file system access engine 360 
sends
{ HEAD ~ Scanning engine } 310 sends { TAIL ~ request } 315 to direct file system access engine 360
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH