Made Easy operating system

Question

Consider a virtual system with 2 level paging. 32 bit virtual address is used to support 32 bit physical address. Page size is 4096 bytes and page table has 4 bytes of page table entry. How many memory accesses are required to read or write a single word?

a)2

b)3

c)4

d)5

Answer 1

According to my understanding, accessing the frame means we get all those words...

it is a 1-level paging ===> you have one Page Table but it should be kept somewhere in Memory

∴ Accessing Page Table Frame + Accessing required Page Frame ===> 2 Memory Read operations required

 

it is a 2-level paging ===> you have one Page Table but it should be kept somewhere in Memory

∴ Accessing 1^st Page Table Frame + Accessing 2^nd Page Table Frame + Accessing required Page Frame ===> 3 Memory Read operations required

 

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it is a n-level paging ===> n+1 Memory Read operations required

Comments

I also think that .but  When page fault accure then ???

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yes, page fault may occur at any time, therefore we can not give exact value but we can give upper bound and lower bound only.... for getting exact value we have to consider no page faults..

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Ok