{TAIL ~ Each processor} has {HEAD ~ its own cache directory} and image directory that duplicate each other non atomically 
{ TAIL ~ Each processor } has { HEAD ~ its own cache directory } and image directory that duplicate each other non atomically
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH