If {TAIL ~ the local CPU} addresses {HEAD ~ a memory module} which is different from the last accessed memory module, then the subsystem monitoring circuit initiates a request to maintain control of the system bus 
If { TAIL ~ the local CPU } addresses { HEAD ~ a memory module } which is different from the last accessed memory module , then the subsystem monitoring circuit initiates a request to maintain control of the system bus
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD 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