VIrtual Paging :Basic Question closed

Question

If we say virtual address is 34 bit and we use 3 level page table.

12 bits page offset.

first level page table =9 bits

second level page table = 5 bits

third level page table =8 bits.

My question is in third level page table there is 2^8 entries

what is meant by second level page and first level page table ?

If possible please draw diagram .

Answer 1

In a 34-bit machine we subdivide the virtual address into 4 segments as follows:

9

5

8

12

first level page table =9 bits , second level page table = 5 bits and third level page table =8 bits.

12 bits page offset. The last bits of the virtual address are called the offset which is the location difference between the byte address you want and the start of the page. 

what is meant by second level page and first level page table ?

The first level is page field 9 bits . That means the page size is 2⁹ =  512 Bytes . Program's address space have 512 pages .

The first level page table points to 512 2nd  level page tables, each pointing to 32 3rd page tables, each containing 256 pages .

Comments

In 2nd level have 2⁵ = 32 page entries.

Now, first level page table points to 512  second level page tables, each of these pointing to 32 third level page tables, 

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and similarly there are 32 page tables which where each page table has 2^8 entries and  in last ones there are  2^8 table with offset pointing it..rt?

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yes , right .