Preferably, after the earliest region is determined, the control portion updates at appropriate times the history information stored in the determined earliest region in accordance with progress of {TAIL ~ the constant procedure} before end or interruption of the constant procedure in {HEAD ~ the input/output processing} 
Preferably , after the earliest region is determined , the control portion updates at appropriate times the history information stored in the determined earliest region in accordance with progress of { TAIL ~ the constant procedure } before end or interruption of the constant procedure in { HEAD ~ the input / output processing }
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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD