Fault tolerant memory system which utilizes {HEAD ~ data} from a shadow memory device upon the detection of {TAIL ~ erroneous data} in a main memory device 
Fault tolerant memory system which utilizes { HEAD ~ data } from a shadow memory device upon the detection of { TAIL ~ erroneous data } in a main memory device
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH