edited by
1,598 views
2 votes
2 votes
Consider a process of 200 KB which has 2 segments each segment size is 256 KB ,Calculate overhead in segmented paging.The page table entry is 4B, segment table entry is 2 B ,Page size is 2KB.
edited by

2 Answers

1 votes
1 votes

Size of each Segment  = 256 KB

Page Size = 2 KB

→Number of Pages in a segment = 256 / 2  = 128 pages

→Each segment table will have its own page table.

→Number of entries in a page table = Number of pages in a segment = 128

→Page Table Size = (Number of Entries * PTE Size) = 128*4 = 512 B

Now these Page tables should also be present inside the frames and to keep track of which frame these PT are located , we have Segment table. Segment Table will contain pointers to the Page Tables.

No of entries in Segment table = No. of Page Tables = 2

→Size of segment table =( Number of entries in segment table * size of each entry) = 2∗2 = 4 B

 Total Overhead = Total no. of Page Table + Segment Table Size = 512*2 + 4B = 1028 B ANSWER

0 votes
0 votes
SEGMENT 1 (256 KB)
SEGMENT 2 (256 KB)

$\rightarrow$Page Size = $2$ KB

$\rightarrow$Number of Pages in a segement = $\frac{256 KB}{2 KB}$ = $128$ = $2^{7}$

$\rightarrow$Each Table will have its own page table.

$\rightarrow$Number of entries in a page table = Number of pages in a segment = $2^{7}$

$\rightarrow$Page Table Size = (Number of Entries * PTE Size) = $2^{7}*2^{2}$ = $2^{9}$ = $512$ B

$\rightarrow$Size of segement table =( Number of entries in segment table * size of each entry) = $2*2$ B = $4$ B

$\rightarrow$ Total Overhead of $1$ page table = $512$ + $4$ = $516$ B


$\rightarrow$There will be $1$ page table for each segments.i.e. $2$ page table and both page tables will have size=$512$B

$\rightarrow$But in MM only one page table will be present at a time so overhead of one PT is considered in total overhead.

$\rightarrow$The segment table along with one of the page tables will be present in MM.

$\therefore$ Total Overhead = $516$ B

edited by

Related questions

8 votes
8 votes
1 answer
2
Pooja Palod asked Jan 4, 2016
6,276 views
explain similarities and dismilarities between Segmented paging and paged segmentation
2 votes
2 votes
1 answer
4