CY-404 Operating Systems - Jun 2024 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 14 Marks
   Discuss in detail the characteristics and features of the Operating system.
   How to answer

   • Define operating system as resource manager and extended machine
   • List characteristics: concurrency, sharing, long-term storage, etc.
   • Explain features: process management, memory management, file system, security, etc.
   • Give examples of types
2. 7 Marks
   aExplain different types of Linux System Calls.
   How to answer

   • Define system call and its role
   • Classify Linux system calls: process, file, device, info, communication
   • Give examples for each type
   • Explain usage
3. 7 Marks
   bExplain the dual mode of process execution and why it's necessary.
   How to answer

   • Define user mode vs kernel mode
   • Explain privileged instructions and protection
   • Explain mode bit and system call transition
   • Explain why necessary for protection and stability
4. 7 Marks
   aConsider 3 processes $P_1, P_2, P_3$ which require 7, 3 and 6 time units with arrival times 0, 1, 2. Draw the Gant chart and calculate the average waiting time and completion time for each process using the Shortest Job First algorithm.
   How to answer

   • List arrival and burst times for $P_1, P_2, P_3$
   • Apply non-preemptive SJF scheduling order
   • Draw Gantt chart with timeline
   • Calculate completion, turnaround and waiting times and average
5. 7 Marks
   bHow does semaphores help to solve the critical section problem. Explain their operations.
   How to answer

   • Define critical section problem and requirements
   • Define semaphore and types
   • Explain wait/P and signal/V operations
   • Show how semaphores ensure mutual exclusion and synchronization
6. 14 Marks
   Consider the following reference string 1, 2, 3, 4, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6, find the number of page faults that occur using 4 frames for FIFO and LRU algorithms.
   How to answer

   • State reference string and 4 frames
   • Simulate FIFO replacement step-by-step and count faults
   • Simulate LRU replacement step-by-step and count faults
   • Compare results
7. 7 Marks
   aExplain in detail about segmentation with an example.
   How to answer

   • Define segmentation and segment table
   • Explain logical address as segment-number and offset
   • Give example with address translation
   • List advantages like no internal fragmentation
8. 7 Marks
   bDiscuss in detail the advantages and disadvantages of contiguous allocation over disk space allocation strategy.
   How to answer

   • Define contiguous allocation
   • List advantages: simplicity, fast sequential access
   • List disadvantages: external fragmentation, file growth issue
   • Contrast with linked/indexed allocation
9. 7 Marks
   aList and explain the various File protection methods.
   How to answer

   • Define file protection need
   • List methods: passwords, access lists, groups, permissions
   • Explain each method briefly
   • Give Unix-type permission example
10. 7 Marks
    bExplain the following commands: lseek, stat and ioctl with examples.
    How to answer

    • Define lseek with syntax and seek modes
    • Define stat with file status info
    • Define ioctl for device control
    • Give example usage for each
11. 7 Marks
    aExplain the key characteristics of a network operating system and how they differ from traditional operating system.
    How to answer

    • Define network operating system
    • List key characteristics: sharing, communication, security
    • Differentiate from traditional centralized OS
    • Give examples
12. 7 Marks
    bDiscuss in detail about asynchronous operations in I/O management.
    How to answer

    • Define synchronous vs asynchronous I/O
    • Explain non-blocking and callback mechanism
    • Explain buffering and interrupt role
    • List advantages in I/O management
13. 14 Marks
    Write short notes on any two of the following.

    1. a)Real and Virtual Concurrency
    2. b)Dynamic linking and loading
    3. c)File system in Windows
    4. d)Interrupt driven
    How to answer

    • Select any two topics from list
    • Define each with key points
    • Explain with example/diagram
    • Conclude with uses