An IOM tracks the order of instruction execution through the pipeline—that is, which instructions are older or newer than a given instruction—by maintaining representations of {HEAD ~ instructions} in {TAIL ~ true program order}, such as in a circular buffer, FIFO, or the like 
An IOM tracks the order of instruction execution through the pipeline — that is , which instructions are older or newer than a given instruction — by maintaining representations of { HEAD ~ instructions } in { TAIL ~ true program order } , such as in a circular buffer , FIFO , or the like
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH