Demand Paging

Demand Paging ( paging system + swapping):-

Demand paging is used in virtual memory system. Demand  paging system is similar to a paging system with swapping. The processes reside in secondary memory & pages are loaded only on demand  not a advance. when we want to execute a process , we swap it into memory . rather than swapping the entire process into memory , though we use a lazy swapper. lazy swapper swap the page only when it use needed.


Advantage and Disadvantage :- 

  1. reduces the memory requirement
  2. reduces the swap time
  3. increase the multi programming
  4. page fault is disadvantage of Demand Paging.

Page Fault :- page fault used in the performance measurement .


Performance of Demand Paging:-

Ea = [(p+ page fault time )+((1-p)*ma)]

Ea = effective memory access time

p = probability of page fault

1-p = probability of no page fault

ma = general memory access time

4 Replies to “Demand Paging”

  1. Sir my name is pradeep singh nd IT STUDENT . Apke notes bdiya h . Tq

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