?a???s?as?%20t??%20PowerPoint

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PAGING??S?GOG? S?? ???????? ??? ?????? S?????O?
??G???T?O?  

• ? ?????a t?? online a??????µ?? ?a? t??
  a?ta????st???? a????s?? a?t??

• ??sa???? ?a? ???sµ?? t?? p??ß??µat?? t?? paging

• ??d? a????s?? ?a? ßas???? ???sµ??

• ?a???s?as? a??????µ?? ep???s?? t?? paging ?a?
  a????s? t?? ap?d?t???t?ta? t???.

?)?tete?µ???st???? ???????µ?? ?) Randomized
a??????µ??
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? ?????a t?? online a??????µ?? ?a? t??
a?ta????st???? a????s?? a?t??

• ??t?pa?aß??? online- offline p??ß??µ?t??

St?? pe??pt?s? t?? online p??ß??µ?t?? ta ded?µ??a
t?? p??ß??µat?? pa?????ta? st?? a??????µ?
stad?a??, ??a- ??a se ???e st??µ??t?p?
e?t??es?? t?? a??????µ??.
???sµ?? 1 Online a??????µ?? e??a? µ?a d?ad??as?a
? ?p??a se ???e st??µ??t?p? t?? p??ß??µat??, af??
de??e? ??a ded?µ??? d? ?? e?s?d?, pa???e? ??a
ap?t??esµa r? (???d??) µe ß?s? t?s? t? ded?µ???
d? t?? st??µ??t?p?? ? ?s? ?a? ta ded?µ??a d?-? ,
?1, t?? st??µ??t?p?? p?? ????? p??????e?.

• ?a??de??µa ????µß?t?????

• ???? t?? f?s?? t?? online p??ß??µ?t??
  ???s?µ?p????µa?
• d?af??et??? p??s????s?. ??sa???? st??
  a?ta????st???
• a????s?

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??sa???? ?a? ???sµ?? t?? p??ß??µat?? t?? paging

• ????µe µ?a a??? µ??µ? n se??d?? ?a? µ?a ???????
  µ??µ? (cache memory) k se??d?? (ngtk).

• ?p?t???? p??sp??as? ??st?? 0

• ?p?t???µ??? p??sp??as???st?? 1

• St????e?a??st?p???s? s???????? ??st???, d??ad?
• e?a??st?p???s? t?? a???µ?? t?? ap?t?????.

• ? ep???s? ???p?? t?? p??ß??µat?? t?? paging
  ???e?ta? st??
• e??es? e??? a??????µ?? ß?s? t?? ?p???? ?a
  d??????µe t??
• se??de? ap? t? ??????? µ??µ? p???e?µ???? ?a
  f????µe µ?a
• se??da ap? t?? a??? µ??µ? ?ta? ????µe ap?t???
  p??sp??as?.

• ? a??????µ?? a?t?? ?a ap?s??pe? st? ?a d????e? t?
  se??da
• e?e??? p?? e?d??eta? ?a ?d???se? se ????te?e?
  ap?t???e?
• p??sp??as??

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• ? ap?t?µ?s? e??? online a??????µ?? ???eta? se
  s?????s? µe t??
• a?t?st???? offline.

• ???a? d?a?s??t??? p??fa??? ?t? ? ß??t?st??
  offline a??????µ??
• e??a? ? Longest- Forward- Distance (LFD) d???e
  t? se??da
• e?e??? ? ??t?s? t?? ?p??a? e??a? a???te?a st??
  a???????a
• a?t?se??

• St? online p??ß??µa ? ???e??? ???s?? ??a t??
  µe????t????
• a?t?se?? st? µ??µ? µa? ?d????? st?? a?????
  e??es??
• a??????µ?? p?? ?a ??e? ?s? t? d??at?? ?a??te??
• s?µpe??f??? a?e?a?t?t?? p??a ?a e??a? ?
  µe????t???
• a???????a a?t?se??.

T?O???? 1  ? a??????µ?? LFD (Longest- Forward-
Distance) e??a? ? ß??t?st?? offline a??????µ??
??a t? paging.
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??d? a????s?? ?a? ßas???? ???sµ??

• ?? p?s? ap?d?t???? ? ??? e??a? ??a? a??????µ??
  e?a?t?ta? ?a? ap? t? e?d?? t?? a????s?? t??
  p??ß??µat?? , d??ad? ap? t?? ?pt??? ????a ap? t??
  ?p??a ??????µe t?? ap?te?esµat???t?ta t??
  a??????µ??.

• ?????s? ?e???te??? pe??pt?s?? (worst case
  analysis)?aµ?a p????f???a ??a t??
  ap?te?esµat???t?ta t?? ???e a??????µ??. ???? ??
  a??????µ?? e??s?? a?ap?te?esµat????.

• ?????s? µ?s??-pe??pt?s?? (average-case
  analysis)?d? ??e?a??µaste ??a stat?st???, µ?a
  ?ata??µ? p??a??t?ta? ??a t? ??t?s? t?? d?af????
  se??d?? t?? a???? µ??µ?? .?µ?? ? ??t?s? a????e?
  d??aµ??? µe t? ????? ?a? p?????e? ap? efa?µ??? se
  efa?µ???, µ?a t?t??a p??s????s? de ?a ?ta? ?a?
  t?s? a???p?st?.

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• ?p? ta pa?ap??? a????? e?sa????? t?? ?????a?
  t?? a?ta????st???? a????s??.

• S?????s? t?? ap?d?t???t?ta? t?? online a??????µ??
  µe t?? ap?d?t???t?ta t?? ß??t?st?? offline
  a??????µ?? ??a ???e e?s?d? ?a? ?e????µe t? ????
  t?? d?? ap?d?t???t?t?? st? ?e???te?? pe??pt?s?
  e?s?d??.

• cost A(s)??st?? e??? online a??????µ?? ? ??a
  t?? a???????a e?s?d?? s.

• G?a t? paging t? s e??a? ? a???????a ??t?s?? t??
  se??d?? ?a? cost A(s) ? a???µ?? t?? ap?t?????
  p??sp??as?? t?? ? ??a t?? e?s?d? s.

• ?st? cost OPT(s) t? ??st?? p?? s??ep??eta? ?
  ß??t?st?? offline a??????µ?? ??a e?s?d? s.

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???sµ?? 2 ??µe ?t? ??a? a??????µ?? ? e??a? c-
a?ta????st???? a? ?p???e? sta?e?? b t?t??a ?ste
??a ???e a???????a a?t?se?? s ?s??e? cost A (s)
c cost OPT(s) b (1) ? ?????
a?ta????st???t?ta? t?? a??????µ?? ? s?µß????eta?
µe cA ?a? e??a? t? infimum ???? t?? c ??a ta
?p??a ? ? e??a? c-a?ta????st????.

• ??µe t???? ?t? ??a? a??????µ?? e??a? ?s????
  a?ta????st???? ?ta? ep?t?????e? t?? ?a??te?? ????
  a?ta????st???t?ta? ??a ??a p??ß??µa.

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?a???s?as? a??????µ?? ep???s?? t?? paging ?a?
a????s? t?? ap?d?t???t?ta? t???.
?)?tete?µ???st???? ???????µ??

• ?d? ta ß?µata p?? ?a e?te?est??? e??a?
  ?a????sµ??a ?a? e?a?t??ta? µ??? ap? ta ded?µ??a
  e?s?d?? p?? pa?????ta? st?? a??????µ? ?at? t?
  d????e?a e?t??es?? t??.?e? e???eta? ?aµ?a
  t??a??t?ta.

• G?a t? µe??t? t?? ap?d?t???t?ta? e?s????µe t??
  ?????a t?? a?t?p????.

• ? a?t?pa??? p??spa?e? ?a µa? d?s?????e? t? ???
  ?s? pe??ss?te?? ???eta?.

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• ??e? d?p?? ????

1. ?a???e? µ?a a???????a a?t?se?? ??a t?? online
   a??????µ? ?.

2)????e? ? ?d??? t?? offline (??a a?t??)
a??????µ? ??a t?? ?d?a a???????a.

• S??p?? t??? a???????a a?t?se?? p?? ?a ep????e?
  ?a p???a??se? t? µ???st? d??at? ??st?? ??a t??
  online a??????µ? ? e?? pa??????a ? offline d????
  t?? a??????µ?? ?a ep?f??t?s?e? µe ?s? µ????te??
  ??st?? ???eta?.

T?O???? 2  G?a ?p????d?p?te ?tete?µ???st???
online a??????µ? ??a t? paging de? µp????µe ?a
ep?t????µe ???? a?ta????st???t?ta? µ????te?? t??
k, ?p?? k t? µ??e??? t?? ???????? µ??µ??
?p?de???
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???tas? ???st?? ?tete?µ???st???? online paging
a??????µ??
T?O???? 3  ? a??????µ?? LFU (List Frequently
Used d???e t? se??da p?? ???s?µ?p??e?ta?
????te?? s????) de? e??a? a?ta????st????. ??e?
µ? f?a?µ??? ???? a?ta????st???t?ta?.
?p?de???
T?O???? 4  ? a??????µ?? LIFO (Last In First Out
d???e t? se??da p?? ?fe?e? te?e?ta?a) ??e?
ep?s?? µ? f?a?µ??? ???? a?ta????st???t?ta?.
?p?de???
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Paging marking Algorithms
p.m.a.   Each phase unmark all the pages for
each request if in fast mark location if
not evict an unmarked location (strictly
determined by the
deterministic algorithm)



put request in fast , mark
location if no unmarked locations, end phase.
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• Me t?? p.m.a de? e?asfa?????µe µe??µ??? ??st??
  ??a µa? Ost?s? e?asfa?????µe ?t? ? offline
  a??????µ?? t?? a?t?p???? ?a ap?t?????e? ???e f???
  p?? ? d???? µa? a??????µ?? ?a ep?f??t??eta? µe
  ??a s???e???µ??? ??st??.

T?O???? 5  ?p???sd?p?te paging marking a??????µ??
e??a? k- a?ta????st????
?p?de???
T?O???? 6  ?? a??????µ?? LRU ?a? FIFO e??a?
ka?ta????st????

• ??af??? ?e???t???? ?a? eµpe?????? ap?te?esµ?t??

• S?µßat??? a?ta????st??? a????s? ?a? ???e? µ??f??
• a?ta????st???? a????s??

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?) Randomized a??????µ??
???????µ?? p?? ?????? t??a?e? ep?????? ?at? t?
d????e?a e?t??es?? t???.

• ? t??a??t?ta p?? ?p???e? st??? Randomized
  a??????µ??? µp??e? ?a µe??se? t?? ????
  a?ta????st???t?ta?

• ??sa???? ???? e?????? ?a? ep??tas? pa???? p??
  ???s?µ?p??????a? ??a t?? a????s? t??
  ?tete?µ???st???? a??????µ??.

1)??st?? a?aµe??µe?? ??st??.
2)???s???? ?a? ????? µ??t???? a?t?p????

• ?d??? d?p??? ?????. ??af???p?????ta? ?? p??? t?
  se p??? ßa?µ? ????????? t?? t??a?e? ep?????? t??
  online a??????µ??

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   ????µ?? a?t?pa??? (oblivious adversary)

• ep????e? ???????? t?? a???????a a?t?se?? s e? t??
  p??t???? ????? ?a ??????e? ta ap?te??sµata t??
  t??a??? ep?????? t?? online a??????µ??.

• ?? ??st?? µe t? ?p??? ??e??eta? ? a???µ??
  a?t?pa??? e??a? t? ??st?? t?? ß??t?st?? offline
  a??????µ?? ??a t?? a???????a s.

   ???sa?µ?st???? online a?t?pa??? (adaptive
online adversary)

• ??e? ep????s? t?? st??µ??t?p?? e?t??es?? t??
  online a??????µ??

• ?a???e? t?? ep?µe?? a?t?s? µe ß?s? t?? (t??a?e? )
  ep?????? t?? online a??????µ?? s ??e? t??
  p??????µe?e? a?t?se??.

• ?e????eta? online ???e µ?a ap? t?? a?t?se?? t??
  a???????a? s p?? pa???e? ????? ?a ??????e? t??
  t??a?e? ep?????? t?? online a??????µ?? ??a t??
  pa???sa ?a? t?? µe????t???? a?t?se??.

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???sa?µ?st???? offline a?t?pa??? (adaptive
offline adversary)

• E?e? ep????s? t?? st??µ??t?p?? e?t??es?? t??
  online a??????µ??

• ??a???e? ???e a?t?s? t?? a???????a? a?t?se?? s µe
  ß?s? t?? ep?????? p?? ??e? ???e? ? online
  a??????µ?? ??a ??e? t?? p??????µe?e? a?t?se??.

• G?????e? ?µ?? ??? t?? a???????a a?t?se?? s p??
  ??e? d?µ??????se? ?a? ?ts? µp??e? ?a t?
  ?e????eta? µe t? ß??t?st? ??st??.

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???sµ?? 3 ??µe ?t? ??a? Randomized online
a??????µ?? ? e??a? c-a?ta????st???? ?? p???
??p??? t?p? a?t?p???? ADV a? ?p???e? a ?ts? ?ste
??a ???e a?t?pa?? t?? t?p?? ADV ?a ?s??e? Ecost
A(s)- c cost ADV(s) a
s a???????a a?t?se?? p?? pa???e? ? a?t?pa???
?at? t?? a????ep?d?as? t?? µe t?? ? cost ADV(s)
t? ??st?? p?? ? s s??ep??eta? ??a t?? a?t?pa??.

• ? ????? a?ta????st???t?ta? e??? randomized
  a??????µ?? ? ?? p??? a?t?pa?? t?? t?p?? ADV
  ????eta? ??
• cAADVinfc\ A e??a? c- a?ta????st???? ??a ?????
  t??? a?t?p????? t?p?? ADV

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?a?at???se?? p??? st?? ???sµ?
? µ?s? t?µ? ?aµß??eta? ?? p??? t?? t??a?e?
ep?????? p?? ???e? ? randomized a??????µ?? ? ?at?
t?? e?t??es? t??.
? ????? a?ta????st???t?ta? de? ?a?a???eta? p?????
ap? t?? online a??????µ? ? a??? µetaß???eta?
a?????a ?a? µe t? µ??t??? t?? a?t?p???? p??
????µe ???s?µ?p???se? ??a ?a p?a?µat?p???s??µe
t?? a?ta????st??? µa? a????s?.
G?a t?? a???µ??a a?t?pa?? pa???e? t? µ??f?
Ecost A(s) c cost OBL(s) a.
G?a t??? p??sa?µ?st????? a?t?p????? pa???e? t?
µ??f? Ecost A(s)
Eccost ADAPT(s) a
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T?O???? 7  ?st? COBL ? ß??t?st?? ?????
a?ta????st???t?ta? p?? µp??e? ?a ep?te???e? ??
p??? ??a? a???µ??a a?t?pa?? ??a ??p??? p??ß??µa.
?st? d??ad? ?t? COBL infAcAOBL . ?µ??a ??????µe
CADON infAcAADON ?a? CADOFF infAcAADOFF. ?st?
t???? ?t? CDET e??a? ß??t?st?? ?????
a?ta????st???t?ta? p?? µp??e? ?a ep?te???e? ap?
??a? ?tete?µ???st??? a??????µ?. ??te
?s??e? COBL CADON CADOFF CDET .
??a?s??t??? d??a??????s?

• ?? ??t? f???µa p?? ß???aµe ??a t???
  ?tete?µ???st????? a??????µ??? µp??e? ?a epe?ta?e?
  ?ste ?a ?s??e? ?a? ??a t??? randomized
  a??????µ??? ?? p??? ??a? p??sa?µ?st??? online
  a??????µ?.

• S??ep?? ? ???s? randomized a??????µ?? ??a?t?
  p??sa?µ?st???? a?t?p???? de µa? d??e? ?a???a
  p?e????t?µa.

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S?µpe??f??? ?a? ap?d?t???t?ta ??p???? randomized
paging a??????µ?? ?? p??? t?? a???µ??a a?t?pa??.
1)???????µ?? RAND Se ???e ap?t???a d???e ap?
t? µ??µ? µ?a se??da st?? t???.

• ???????µ?? d???? µ??µ?

• ? a??????µ?? RAND e??a? k-a?ta????st???? ?? p???
  ?p????d?p?te a???µ??a a?t?pa??.

T?O???? 8 ?p???sd?p?te a??????µ?? ????? µ??µ?
??a t? k-server p??ß??µa se ?p????d?p?te µet????
???? ??e? ???? a?ta????st???t?ta? t??????st?? k
?? p??? t?? a???µ??a a?t?pa??
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2)???????µ?? RMA (Randomized Marking Algorithm)
???????µ?? µe µ??µ?
T?O???? 9 ? Randomized Marking ???????µ?? RMA
??e? ???? a?ta????st???t?ta? 2?(k) ??a?t?
?p????d?p?te a???µ??a a?t?p???? ?p?? ?(k)
?p?de???
????sµa 1 ?ta? ? s???????? a???µ?? t?? se??d?? ?
t?? a???? µ??µ?? e??a? k1 t?te ? RMA e??a?
?(k)-a?ta????st????.
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T?O???? 10 ?st? R ??a? ?p???sd?p?te Randomized
paging a??????µ??. ?? ? a???µ?? t?? se??d?? e??a?
µe?a??te??? ? ?s?? t?? k1,?p?? k e??a? t?
µ??e??? t?? ???????? µ??µ??, t?te ? ?????
a?ta????st???t?ta? t?? R ??a?t? ?p??d?p?te
a???µ??a a?t?p???? e??a? µe?a??te??? ? ?s?? t??
?(k).
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S??se?? a??µesa st?? ap?d?t???t?te? t??
a??????µ?? ??a t??? t?e?? t?p??? a?t?p????

• ? ?s??? e??? randomized a??????µ?? µet??ta? ap?

t?? ???? a?ta????st???t?ta? p?? a?t?? ep?t?????e?
t?? ?s?? t?? a?t?p???? p?? ??e? ?a a?t?µet?p?se?.
T?O???? 11  ?st? G ??a? online a??????µ?? µe
???? a?ta????st???t?ta? a ??a?t? e???
p??sa?µ?st???? online a?t?p???? ?a? ?st? ?t?
?p???e? online a??????µ?? ? µe ????
a?ta????st???t?ta? ß ??a?t? e??? a???µ??a
a?t?p????. ??te ? G e??a? aß-a?ta????st????
??a?t? t?? p??sa?µ?st???? offline a?t?p????.
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T?O???? 12  ?st? G ??a? a-a?ta????st????
a??????µ?? ??a?t? e??? p??sa?µ?st???? offline
a?t?p????. ??te ?p???e? ?tete?µ???st????
a??????µ?? p?? ??e? ???? a?ta????st???t?ta? a.
????sµa 2 ?st? G ??a? Randomized a??????µ?? p??
e??a? c- a?ta????st???? ??a?t? e???
p??sa?µ?st???? online a?t?p????. ?? ?p???e?
a??????µ?? d-a?ta????st???? ?? p??? a???µ??a
a?t?pa?? t?te ?p???e? ?a? ?tete?µ???st????
cda?ta????st???? a??????µ?? .
????sµa 3 ?st? G ??a? randomized a??????µ?? p??
e??a? c- a?ta????st???? ??a?t? e???
p??sa?µ?st???? online a?t?p????. ??te ?p???e?
?tete?µ???st???? c2- a?ta????st???? a??????µ??.