writing {TAIL ~ the predetermined data} to a log block corresponding to {HEAD ~ a data block} containing the page 
writing { TAIL ~ the predetermined data } to a log block corresponding to { HEAD ~ a data block } containing the page
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH