{HEAD ~ Each node} of the queue holds {TAIL ~ a reference} to a task that may be concurrently performed by multiple thread execution units, but each on a different subset of data 
holds
{ HEAD ~ Each node } of the queue holds { TAIL ~ a reference } to a task that may be concurrently performed by multiple thread execution units , but each on a different subset of data
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH