The queue has a corresponding scheduler level M, where M is {HEAD ~ a positive integer} less than or equal to {TAIL ~ N} 
The queue has a corresponding scheduler level M , where M is { HEAD ~ a positive integer } less than or equal to { TAIL ~ N }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL