1
GATE CSE 2025 Set 2
MCQ (More than One Correct Answer)
+2
-0.67

Consider a demand paging system with three frames, and the following page reference string: 1 2 3 4 5 4 1 6 4 5 1 3 2 . The contents of the frames are as follows initially and after each reference (from left to right):

GATE CSE 2025 Set 2 Operating Systems - Memory Management Question 2 English

The *-marked references cause page replacements.

Which one or more of the following could be the page replacement policy/policies in use?

A
Least Recently Used page replacement policy
B
Least Frequently Used page replacement policy
C
Most Frequently Used page replacement policy
D
Optimal page replacement policy
2
GATE CSE 2025 Set 2
Numerical
+2
-0

A computer system supports a logical address space of 232 bytes. It uses two-level hierarchical paging with a page size of 4096 bytes. A logical address is divided into a b-bit index to the outer page table, an offset within the page of the inner page table, and an offset within the desired page. Each entry of the inner page table uses eight bytes. All the pages in the system have the same size. The value of $b$ is _________ . (Answer in integer)

Your input ____
3
GATE CSE 2025 Set 1
Numerical
+2
-0

In optimal page replacement algorithm, information about all future page references is available to the operating system (OS). A modification of the optimal page replacement algorithm is as follows:

The OS correctly predicts only up to next 4 page references (including the current page) at the time of allocating a frame to a page.

A process accesses the pages in the following order of page numbers:

$$1,3,2,4,2,3,1,2,4,3,1,4$$

If the system has three memory frames that are initially empty, the number of page faults that will occur during execution of the process is __________ (Answer in integer)

Your input ____
4
GATE CSE 2024 Set 2
Numerical
+2
-0

Consider a 32-bit system with 4 KB page size and page table entries of size 4 bytes each. Assume 1 KB = $2^{10}$ bytes. The OS uses a 2-level page table for memory management, with the page table containing an outer page directory and an inner page table. The OS allocates a page for the outer page directory upon process creation. The OS uses demand paging when allocating memory for the inner page table, i.e., a page of the inner page table is allocated only if it contains at least one valid page table entry.

An active process in this system accesses 2000 unique pages during its execution, and none of the pages are swapped out to disk. After it completes the page accesses, let $X$ denote the minimum and $Y$ denote the maximum number of pages across the two levels of the page table of the process.

The value of $X+Y$ is __________.

Your input ____
GATE CSE Subjects
Software Engineering
Web Technologies
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12