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