GATE - 2004 | OS | In a virtual memory system, size of virtual address is 32-bit, size of

GATE - 2004 | OS | In a virtual memory system, size of virtual address is 32-bit, size of
Posted on 22-02-2022

GATE - 2004 [Operating System]

Question:

In a virtual memory system, size of virtual address is 32-bit, size of physical address is 30-bit, page size is 4 Kbyte and size of each page table entry is 32-bit. The main memory is byte addressable. Which one of the following is the maximum number of bits that can be used for storing protection and other information in each page table entry?

A

2

B

10

C

12

D

14

   

Solution:

Option (D) is Correct.

Page table entry must contain bits for representing frames and other bits for storing information like dirty bit, reference bit, etc.
No. of frames = Physical memory size/Page size
= (230)/(212)
= 218
18+4 = 32 (PT entry size = 32 bits)
k = 14 bits

 

Thank You