{HEAD ~ A linked list} 1908 contains {TAIL ~ the remaining available blocks}, called the block pool 
contains
{ HEAD ~ A linked list } 1908 contains { TAIL ~ the remaining available blocks } , called the block pool
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH