CS-405 Operating Systems - Jun 2026 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
   aExplain the evolution and characteristics of modern operating systems.
   How to answer

   • Definition of modern operating system and its goals
   • Evolution stages: batch, multiprogramming, time-sharing, personal, distributed, real-time/mobile
   • Characteristics: resource management, concurrency, protection, portability, security
2. 7 Marks
   bDiscuss operating system services and the role of system calls in resource management.
   How to answer

   • List of OS services: UI, program execution, I/O, file, communication, error detection
   • System calls interface between user and kernel
   • Role in resource management: CPU, memory, device and protection via calls
3. 7 Marks
   aExplain file systems and disk organization.
   How to answer

   • File system definition, files, directories and operations
   • Disk physical organization: platters, tracks, sectors, blocks
   • Logical organization and access methods
4. 7 Marks
   bCompare contiguous and indexed file allocation methods.
   How to answer

   • Contiguous allocation: concept, directory with start/length
   • Indexed allocation: index block and pointers
   • Comparison on fragmentation, access speed, reliability and growth
5. 7 Marks
   aExplain the process life cycle and process management.
   How to answer

   • Process definition and PCB
   • Life cycle states: new, ready, running, waiting, terminated
   • Process management functions: scheduling, creation, termination, IPC
6. 7 Marks
   bCompare common CPU scheduling algorithms and explain the criteria used for their evaluation.
   How to answer

   • Common algorithms: FCFS, SJF, Priority, Round Robin
   • Comparison on preemption, starvation, overhead
   • Evaluation criteria: CPU utilization, throughput, turnaround, waiting, response time
7. 7 Marks
   aExplain the concept of threads and multiple processor scheduling.
   How to answer

   • Thread definition vs process, user vs kernel threads
   • Benefits: responsiveness, resource sharing, economy
   • Multiple processor scheduling: asymmetry, load sharing, affinity
8. 7 Marks
   bDiscuss process management system calls and their importance.
   How to answer

   • Categories: process control, fork, exec, wait, exit
   • How calls invoke kernel mode transition
   • Importance for creation, synchronization and protection
9. 7 Marks
   aCompare partitioning, paging and segmentation techniques.
   How to answer

   • Partitioning: fixed vs variable, fragmentation
   • Paging: pages, frames, page table
   • Segmentation: logical segments, comparison table
10. 7 Marks
    bDiscuss paged segmentation and virtual memory with demand paging.
    How to answer

    • Paged segmentation: segment divided into pages, two-level translation
    • Virtual memory concept and benefits
    • Demand paging: page fault handling, performance with effective access time
11. 7 Marks
    aExplain overlays, dynamic loading and dynamic linking.
    How to answer

    • Overlays: manual partitioning for limited memory
    • Dynamic loading: routine loaded on demand
    • Dynamic linking: linking delayed till execution with stub
12. 7 Marks
    bDiscuss memory management issues associated with large program execution.
    How to answer

    • Problem of large programs exceeding physical memory
    • Issues: fragmentation, swapping overhead, thrashing
    • Solutions: virtual memory, paging, segmentation
13. 7 Marks
    aExplain I/O programming principles and I/O interfaces.
    How to answer

    • I/O programming: programmed I/O, interrupt-driven, DMA
    • I/O interfaces: device controllers, drivers, ports
    • Blocking vs non-blocking interfaces
14. 7 Marks
    bCompare asynchronous and concurrent I/O operations.
    How to answer

    • Asynchronous I/O: non-blocking, overlap of CPU and I/O
    • Concurrent I/O: multiple operations in parallel
    • Comparison on control complexity, performance and use cases
15. 7 Marks
    aExplain synchronization using binary and counting semaphores with WAIT operations.
    How to answer

    • Semaphore definition and WAIT/SIGNAL operations
    • Binary semaphore for mutual exclusion
    • Counting semaphore for resource pools with example
16. 7 Marks
    bCompare Unix/Linux and Windows operating systems.
    How to answer

    • Architecture: kernel design, open-source vs proprietary
    • Features: file system, security, GUI vs CLI
    • Comparison table on use cases, stability and cost