The Gateway to Computer Science Excellence
First time here? Checkout the FAQ!
x
0 votes
29 views

https://gateoverflow.in/872/gate2002-19

IN THE SOLUTION GIVEN BY Akash Kanase  I am not getting the reason behind  using  this formula

No. of bits in first level page table to address a second level page table is log2 of

Physical memory size /(#Entries in a Second level page table × PTE size) ...why we are using PA

AND HOW THE MAXIMUM NUMBER OF PAGETABLES IN 2ND LEVEL CAN BE 220 ....??

asked in Operating System by Loyal (7.1k points) | 29 views
0
Question can be solved without that formula too!

PTE = 4B = 32bits

A PTE contains frame number + protection & other info, so if we first find Frame number, which is

Frame Number = Physical Address - Page offset

                        = 32 - 12 = 20.

Now, PTE = Frame Number + protection & other info

          32   =           20               + protection & other info

        protection & other info = 12 bits.
0

 log2 of Physical memory size /(#Entries in a Second level page table × PTE size)

in-direct formula for finding no.of bits required for identifying a frame

 How?

(#Entries in a Second level page table × PTE size) = page size

Physical memory size/ page size = no.of frames

 log2 ( no.of frames ) =  no.of bits required for identifying a frame

 

 HOW THE MAXIMUM NUMBER OF PAGETABLES IN 2ND LEVEL CAN BE 220

i didn't get this 

0

OK THANKS FOR FORMULA  I GOT ...........BUT AT MADEEASY TEACHER TOLD THAT THE NUMBER OF BITS REMAINS SAME WHATEVER BE THE PAGING LEVEL SO GOT CONFUSED NOW CLEAR

AND YOU DIDNT GET HOW THE MAXIMUM NUMBER OF PAGETABLE IN 2ND LEVEL CAN BE 220 OR U DIDNT GET WHAT I AM ASKING???

0

U DIDNT GET WHAT I AM ASKING???

yes

 

  MAXIMUM NUMBER OF PAGETABLE IN 2ND LEVEL

check this term 

0

JUST LOOK THE DIAGRAM IN THE ANSWER OF THE QUESTION ....iT IS WRITTEN THAT UPTO MAXIMUM 220

2ND LEVEL PAGETABLES ARE POSSIBLE....

0

now i understood your question but i didn't understand that point in the answer.

i hope it would be 

 UPTO MAXIMUM 220 2ND LEVEL PAGE TABLES ENTRIES ARE POSSIBLE due to only 220 frames in the memory

 

0
YA SAME I WAS THINKING

Please log in or register to answer this question.

Related questions

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
50,049 questions
53,194 answers
184,527 comments
70,400 users