1 votes 1 votes I AM GETTING 12KB ????PLEASE CHECK eyeamgj asked Aug 14, 2018 eyeamgj 765 views answer comment Share Follow See all 18 Comments See all 18 18 Comments reply Shubhgupta commented Aug 14, 2018 reply Follow Share I am getting answer 4100 KB because memory overhead is nothing but extra space required by page tables in multilevel paging. Size of page table1 = 4 MB Size of page table2 = 4KB Total Overhead = 4096KB + 4KB = 4100KB 3 votes 3 votes Shaik Masthan commented Aug 14, 2018 reply Follow Share Is answer given 8? 0 votes 0 votes eyeamgj commented Aug 14, 2018 reply Follow Share NO ANSWER GIVEN IS 4100..i WAS JUST DOING MATHEMATICAL MISTAKE WHILE COUNTING NUMBER OF PAGETABLES OF 2ND LEVELS THERE WILL BE 1K PAGETABLES IN 2ND LEVEL ...I WAS COUNTING 2 0 votes 0 votes srestha commented Aug 24, 2018 reply Follow Share how 4MB in inner page table? 0 votes 0 votes Shubhgupta commented Aug 24, 2018 reply Follow Share @Srestha, No. of entries in 1st level PT = $2^{32}(VA)/2^{12}(PS) = 2^{20}$ size of 1st level PT = $2^{20}(no. of entries) * 2^{2}(PTE size) = 2^{22}bytes = 4MB$ 1 votes 1 votes srestha commented Aug 24, 2018 reply Follow Share ok :) but it is given each page table occupy 1 page how is it possible? here 1 page size 4MB and another page size is 4KB right? 0 votes 0 votes Shubhgupta commented Aug 24, 2018 reply Follow Share @srestha, I think it means that there can be many level 1 page table possible and size of each page table is 4KB(Page Size). So in our case there are 2^10 level 1 page table are possible with size 2^12 so total size of level 1 page tables is 4MB and 1 page table at level 2 with size 2^12 so total size of level page tables is 4KB. 0 votes 0 votes srestha commented Aug 24, 2018 reply Follow Share and how size of pages related to size of page table? 0 votes 0 votes Shubhgupta commented Aug 24, 2018 reply Follow Share as mentioned in question that each page table occupy 1 page. So we have 1024(2^10) no. of page tables in level 1 and each can hold one page and page size given is 2^12 bytes So total size of level one page tables = No. of level 1 page tables * size of each page table = 2^10 * 2^12 = 2^22 = 4MB 0 votes 0 votes srestha commented Aug 24, 2018 reply Follow Share total size of level one page tables = No. of level 1 page tables * size of each page table this is not correct size of level one page tables =no of pages* size of pages Now it is told, each page table occupies 1 page that means size of level one page tables = size of pages right? Now size page table varies means size of pages also varies then it means same process contians different size of pages is it really happens? 0 votes 0 votes Shubhgupta commented Aug 24, 2018 reply Follow Share @srestha, means you are saying that there can not be more than one page table possible at level 1? 0 votes 0 votes Shubhgupta commented Aug 24, 2018 reply Follow Share This is what i understood from this question- 0 votes 0 votes Shaik Masthan commented Aug 25, 2018 reply Follow Share @srestha mam then it means same process contains different size of pages no.. it can't happens..... may be internal fragmentation happens ( but note that in multi-level paging internal fragmentation occurs in only last page of outer page table. atmost internal fragmenation occuring in one page we can't change architecture ( Page size ), just we leave it as internal fragmentation only ) each page occupies one page By this statement questioner delivers that there is no internal fragmentation.( But this information doesn't help us ) 0 votes 0 votes srestha commented Aug 25, 2018 reply Follow Share Size of page table1 = 4 MB Size of page table2 = 4KB and each page table occupies 1 page then how page size different here? 0 votes 0 votes Shaik Masthan commented Aug 25, 2018 reply Follow Share then how page size different here? Page table sizes are different but not the Page Size 0 votes 0 votes Ayush Upadhyaya commented Oct 22, 2018 reply Follow Share Outer page table will take 4KB of space and since all 1024 entries of outer level PT are valid, hence all second level Page tables will also be stored in memory. Second level PT overhead=4MB 0 votes 0 votes adarsh_1997 commented Oct 22, 2018 reply Follow Share @ayush upadhyaya outer level PT overhead will be 4kb and inner pt overhead will be 4MB,since outer page table will completely fit into one frame of MM. 0 votes 0 votes Rackson commented Oct 24, 2018 reply Follow Share here the page table of second is only 4 Kb because the first level of the page table is 4MB is so that it can't fit in one page than we divide the no. pages of the First level page table than we got 1 KB and one I kb is easily fit into 4 Kb page ..? 0 votes 0 votes Please log in or register to add a comment.