B.TechSemester 42024-25Operating SystemBCS401

Operating System (BCS401) - AKTU Question Paper 2024-25

B.Tech · Semester 4 · Free PDF Download

This is the official AKTU Operating System Previous Year Question Paper for B.Tech Semester 4, academic session 2024-25. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.

Course:B.Tech

Semester:Semester 4

Session:2024-25

University:AKTU / UPTU

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Questions Asked in 2024-25

Operating System (BCS401) — complete question paper · 70 marks · 3 Hours

Section AAttempt all q u e s t i o n s i n b r i e f . 02 x 7 = 14

a
What are the primary functions of an operating system?
b
A system has 3 processors and 5 programs ready for execution. In how many ways can the processors be assigned to the programs assuming ea ch processor executes one program at a time?
c
What is the difference between a process and a program?
d
In a Producer-Consumer system, the buffer size is 4. If Produc er produces 6 items and Consumer consumes 3, find the number of items in the buffer at the end

A process executes the following code:

fork();
fork();
fork();
How many processes are created in total, including the original?
fork();
fork();
fork()

f
List three components stored in a PCB
g
What is the purpose of a pa ge replacement algorithm?

Section BAttempt any three o f t h e f o l l o w i n g : 07 x 3 = 21

a
Explain the process concept i n detail with its states and state transition diagram
b
Consider the set of processes with arrival time (in millisec onds). CPU burst time (in milliseconds), and priority (0 is the highest priority ) shown below. None of the processes have I/O burst time. Process Arrival Time Burst Time Priority Draw the Gantt chart and find average waiting time using preemp tive priority scheduling algorithm. Process Arrival Time Burst Time Priority
c
Compare and contrast FCFS, SJF, and Round Robin scheduling a lgorithms
d
In optimal page replacement algorithm, information about all future page references is available to the operating system (OS). A modific ation of the optimal page replacement algorithm is as follows: The OS correctly predicts only up to next 4 page references (in cluding the current page) at the time of allocating a frame to a page. A pr ocess accesses the If the system has three memory frames that are initially empty, find the number of page faults that will occur during execution of the process

Section CAttempt any one p a r t o f t h e f o l l o w i n g : 07 x 1 = 07

a
Discuss the differences between Batch, Interactive, and Time Sharing Operating Systems with real-world applications
b
Two semaphores S1 and S2 are both initialized to 1. Process P1 executes wait(S1); wait(S2); and P2 executes wait(S2); wait(S1);. Explai n how a deadlock may occur and under what sequence
a
Define the Critical Section Problem and list the conditions that a solution must satisfy
b
A system shares 9 tape drive s . T h e c u r r e n t allocation and ma ximum requirement of tape drives for three processes are shown below: Process Current Allocation Maximum Requirement Which of the following best describes current state of the system? Explain
2
Safe, Not Deadlocked
3
Not Safe, Deadlocked
4
Not Safe, Not deadlocked Process Current Allocation Maximum Requirement
2
Safe, Not Deadlocked
3
Not Safe, Deadlocked
4
Not Safe, Not deadlocked
a
Discuss the limitations of Dekker’s and Peterson’s solutions when applied to modern multiprocessor architectures
b
Explain file directories and di rectory structures in operating systems
a
Discuss multiprogramming with variable partitions and how it improves memory utilization
b
Consider a disk queue with requests for I/O to blocks on cyl inders 47,38,121,191,87,11, 92, 10. The C-LOOK scheduling algorithm is used. The head is initially at cylinder number 63, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from 0 to 199 . Calculate the total head movement (in cylinders) required to service these requests
a
Consider a demand paging memory management system with 32-bi t logical address, 20-bit physical address, and page size of 2048 bytes. Assuming that the memory is byte addressable, what i s t h e m a x i m u m n u m b e r o f e n t r ies in the
b
Discuss RAID 0, RAID 1, and RAID 5 in detail

Question text is extracted from the official AKTU question paper PDF above. Hindi translations are omitted — every question is printed in English in the original paper. Last verified: 2026-08-23.

Repeated Questions — BCS401

Questions that appeared in more than one session, found by comparing 3 years of Operating System papers (2023-24, 2024-25, 2025-26)

What are the primary functions of an operating system?

Appeared in: 2023-24 · 2024-25 · 2025-26

Consider a disk queue with requests for I/O to blocks on cyl inders 47,38,121,191,87,11, 92, 10. The C-LOOK scheduling algorithm is used. The head is initially at cylinder number 63, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from 0 to 199 . Calculate the total head movement (in cylinders) required to service these requests

Appeared in: 2024-25 · 2025-26

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