Operating System (BCS401) - AKTU Question Paper 2025-26
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 2025-26. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.
Rate this paper
Questions Asked in 2025-26
Operating System (BCS401) — complete question paper · 70 marks · 3 Hours
- aWhat is the main advantage of the layered approach to system design?
- bWhat is interprocess communication? How can it be implemented?
- cA counting semaphore is initialized to 10. Then 6 P (wait) and 4 V (signal) operations are performed on this semaphore. What will be the resulting value of the semaphore?
- dIllustrate the reason for the convoy effect in process scheduling
- eWhat are the necessary conditions for deadlock in an operating system?
- fWhat is locality of reference in demand paging?
- gExplain seek time and rotational latency while accessing the disk
- aThe services and functions provided by an operating system can be divided into two main categories. Briefly describe the two categories and discuss how they differ
- bDescribe the actions taken by a kernel to context-switch between processes
- cConsider a system consisting of m resources of the same type being shared by n processes. A process can request or release only one resource at a time. Show that the system is deadlock free if the following two conditions hold: i. The maximum need of each process is between one resource and m resources. ii. The sum of all maximum needs is less than m + n
- dExplain the working of the Translation Lookaside Buffer (TLB) along with the page 4 K2 (SEM. IV) THEORY EXAMINATION 2025-26 OPERATING SYSTEM table in address translation, with a neat diagram
- eWhat are the advantages of using RAID architecture in disk drive? Explain in detail
- aWhat is the main advantage of the microkemel approach to system design? How do user programs and system services interact in a microkernel architecture?
- bDiscuss the classification of operating systems and provide real-world examples for each type
- aConsider the set of processes with arrival time (in milliseconds) and CPU burst time (in milliseconds) shown below. None of the processes have I/O burst time. Draw the Gantt chart and calculate the Average Waiting Time and Average Turnaround Time using the preemptive Shortest Job First (SJF) scheduling algorithm. Process Arrival Time Brust Time
- bWhat is a Process Control Block? Explain its role in process management
- aWhat do you mean by critical section? how semaphore can be used to ensure
synchronization in critical section? Each process Pi, i =1…….9 is coded as follows: Repeat (SEM. IV) THEORY EXAMINATION 2025-26 OPERATING SYSTEM P(mutex){ critical section } V(mutex) Forever The code for P 10 is identical except that it uses V(mutex) in place of P(mutex). What is the largest number of processes that can be inside the critical section at any moment? Explain - bConsider the following snapshot of a system: Allocation ABCD ABCD Available ABCD Answer the following questions using the banker’s algorithm: i. What is the content of the matrix Need? ii. Is the system in a safe state? iii. If a request from thread T1 arrives for (0,4,2,0), can the request be granted immediately?
- aGiven five memory partitions of 100 KB, 500 KB, 200 KB, 300 KB, and 600 KB (in order), how would the first -fit, best-fit, and worst -fit algorithms place processes of 212 KB, 417 KB, 112 KB, and 426 KB (in order)? Which algorithm makes the most efficient use of memory?
- bConsider the virtual page reference string 4 K3 (SEM. IV) THEORY EXAMINATION 2025-26 OPERATING SYSTEM on a demand paged virtual memory system running on a computer system that has main memory size of 4 page frames which are initially empty. How many pages faults will occur if the program uses: LRU and Optimal Page replacement techniques
- aConsider a disk queue with requests for 𝐼/𝑂 to blocks on cylinders 47,38,121,191,87,11,92,10. 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. What is the total head movement (in number of cylinders) incurred while servicing these requests if C -SCAN and C -LOOK disk scheduling algorithms are used?
- bExplain the followings in detail: i. Direct Memory Access ii. Interrupt iii. Polling
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 necessary conditions for deadlock in an operating system?
Appeared in: 2024-25 · 2025-26
Consider a disk queue with requests for 𝐼/𝑂 to blocks on cylinders 47,38,121,191,87,11,92,10. 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. What is the total head movement (in number of cylinders) incurred while servicing these requests if C -SCAN and C -LOOK disk scheduling algorithms are used?
Appeared in: 2024-25 · 2025-26
Operating System — Other Year Papers
AKTU Operating System PYQs from other sessions
More B.Tech Semester 4 (2025-26) Papers
Other subjects from same semester and session
Syllabus & More PYQs
Paper solve karne se pehle unit-wise syllabus dekh lo