Enhanced Second-Chace Algorithm considers the Refrence(read or written)Bit and the Modify(written) Bit as
an ordered pair(r,m).
(0,0)--neither recently used nor modified(best page to replace)
(0,1)--not recently used but modified(not quit as good, because the page will need to be written out before
replacement
(1,0)--recently used but clean (it probably will be used again soon)
(1,1)--recenty used and modified(it probably will be used again soon, and the page will be need to be
written ou