CY-404 Operating Systems - Dec 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. 7 Marks
   aDiscuss in detail the services of an operating system.
   How to answer

   • Define OS services and user vs system view
   • List major services: UI, program execution, I/O, file system, communication, error detection
   • System services: resource allocation, accounting, protection and security
   • Brief purpose of each service
2. 7 Marks
   bExplain some utility programs supported in the operating system.
   How to answer

   • Define utility programs / system programs
   • Categories: file management, status, programming support, communications
   • Examples: editors, compilers, backup, disk tools
   • Distinction from kernel and application programs
3. 7 Marks
   aWith a neat sketch explain the structure of an operating system.
   How to answer

   • Present layered / modular structure diagram of OS
   • Explain layers: hardware, kernel, system calls, shell, applications
   • Role of kernel, drivers, interfaces
   • Neat labelled sketch
4. 7 Marks
   bDescribe the concept of a process-based kernel and its advantages.
   How to answer

   • Define process-based / microkernel-oriented kernel concept
   • How system functions run as processes/servers
   • Message passing and modularity
   • Advantages: reliability, extensibility, maintainability, security
5. 7 Marks
   aDiscuss in detail the differences between user level and kernel level threads.
   How to answer

   • Define user-level vs kernel-level threads
   • Management, scheduling, context switch, blocking behaviour
   • Advantages/disadvantages of each model
   • Tabular comparison and examples
6. 7 Marks
   bExplain briefly the working of any two deadlock prevention techniques.
   How to answer

   • Define deadlock prevention by negating Coffman conditions
   • Technique 1: e.g., mutual exclusion / hold-and-wait prevention
   • Technique 2: e.g., no preemption / circular wait prevention with ordering
   • Working steps and limitations
7. 14 Marks
   Consider the following reference string $7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1, 7, 0, 1$, find the number of page faults that occur using 3 frames for FIFO and LRU algorithms.
   How to answer

   • State FIFO replacement rule and simulate 3 frames on given string
   • State LRU replacement rule and simulate 3 frames
   • Count page faults for each algorithm
   • Compare results
8. 7 Marks
   aDefine Virtual memory. Explain in detail the advantages of using virtual memory technique.
   How to answer

   • Define virtual memory and address space separation
   • Demand paging / swapping mechanism
   • Advantages: larger programs, multiprogramming, protection, sharing
   • Reduced I/O and memory cost
9. 7 Marks
   bDiscuss in detail contiguous and linked file allocation methods.
   How to answer

   • Define contiguous allocation: directory, extent, pros/cons
   • Define linked allocation: pointers, FAT, pros/cons
   • Access performance and reliability comparison
   • Diagram of each layout
10. 7 Marks
    aDiscuss in the disk performance parameters with examples.
    How to answer

    • Define seek time, rotational latency, transfer time, etc.
    • Formulas for access time and throughput
    • Example calculation for each parameter
    • Impact on disk performance
11. 7 Marks
    bExplain FCFS and SSTF disk scheduling algorithms with examples.
    How to answer

    • Define FCFS scheduling and service order with example
    • Define SSTF scheduling and nearest-track selection with example
    • Calculate total head movement for example queue
    • Compare advantages and starvation issue
12. 7 Marks
    aDifferentiate between distributed and multiprocessor operating systems.
    How to answer

    • Define distributed OS and multiprocessor OS
    • Coupling, memory, communication, autonomy differences
    • Tabular differentiation on key points
    • Examples of each system
13. 7 Marks
    bDescribe the logical structure of I/O function with an example.
    How to answer

    • Define logical I/O structure layers
    • Functions: device drivers, buffering, spooling, system calls
    • Illustrate with example device operation
    • Block diagram of I/O subsystem
14. 14 Marks
    Write short notes on any two of the following:

    1. a)System calls for Process Management
    2. b)Dynamic linking and loading
    3. c)File system in Unix
    4. d)Kernel I/O subsystem
    How to answer

    • Select any two topics from a-d
    • Give definition and key concepts for each
    • Explain working with example/diagram
    • Mention advantages/uses