Each storage node is dependently linked to one of {TAIL ~ a plurality} of {HEAD ~ index nodes} 
Each storage node is dependently linked to one of { TAIL ~ a plurality } of { HEAD ~ index nodes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD