8/2/2019 Cuoi Ky 3

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Cu 2 : Mt my tnh vi 32 bit a ch s dng bng trang 2 mc . a ch o c chia thnh : 10 bit cao cho trng bng trang mc 1 , 10 bit caocho trng bng trang mc 2 v cn li l a ch Offset .Hi kch thc trang l bao nhiu v c bao nhiu trang .

Gii :T s bit ca offset ==> c kch tht ca 1 page . 12 bit cho offset => 1 trang = 2^12 B = 4 KBBng trang 2 mc mi mc 10 bit ==> s c 2^10 x 2^10 = 2^20 trang

Cu 3 : Mt my c 4 khung trang thi gian np (Loader) thi gian truy cp sau cng (Last set) , bit R v M ca mi trang nh hnh v :

Page Loader Last set R M0 126 279 0 01 320 269 1 02 120 272 1 13 160 280 1 1a) Chn trang thay th theo phng php NRU

b) FIFOc) C hi 2d) LRU

Gii : Ci ny p dng l thuyt , trnh by chc c vi dnga)NRU (Not Recent Used - ko s dng gn y):Phng php ny chn trang loi 0 , nu khng c loi 0 th chn loi 1loai 0: R = M = 0loai 1: R=0 , M= 1

==> page 0b)FIFO ( First In - First Out ) : ai n trc c chnPage 2 c loader = 120 ==> chn page 2c) C hi 2 : Ci tin ca FIFO nhng xt thm RR=0 thi chnR=1 thi t v 0 , xt phn t tip theo==> Page 0

Note : trong trng hp xu , tt c R = 1 th n quay li phng php FIFO . V C hi 2 l ci tin ca FIFO.d) LRU ( Least Recent Used - t s dng nht )p dng cng thc MAX | Last Ref - Last Load | , tm ra trang .Ly 2 thi gian Loader v Set tr nhau , tm ra --> Page 0.

cu 1:Gi s 1 CT c cc phn:text= 16380 byte, data=32768 byte, stack= 32500 byte.Hi CT c np vo b nh 64KB hay ko nu:a. Size ca 1 page=1024byte.

b. Size ca 1 page =512byte.Bit 1 khung trang ca b nh khng cha 2 phn khc nhau.

Cu 2: 1 my tnh vi 32bit a ch o. Hi:a. Size ca CT ti a =?. Bit rng 1 page= 4kb hi c bao nhiu trang CT ca /c o?

b. Nu b nh cp cho CT 640KB hi c ? bit /c vt l v CT ca /c vt l?

Th gii n >"< sai b con ch lin nghena) Size chng trnh ti a: 2^ 32 = 4GB1 page = 4KB => s trag CT ca a ch o: 2^32 / 2 ^ 12 = 2 ^ 20 ( trang)

b) Ta s c s khung trang : 640 / 4 = 160 khung trang==>>> Cn 8 bt bin dinv 1 page = 4Kb==>> cn 12 bt cho a ch offset

==>> vy cn 12+ 8 = 20 bit biu din cho a ch vt l.