CS3451 Introduction to Operating Systems Previous Year Question Papers - Anna University

UNIT I: Operating System Overview

Part A (2 Marks)

• Define Operating System and its primary goals.
• What are System Calls? Provide two examples.
• Differentiate between Kernel Mode and User Mode.
• What is a Virtual Machine?
• List the different types of OS (Batch, Time-sharing, Real-time).

Part B (13 Marks)

• Explain the various Operating System Structures (Monolithic, Layered, Microkernel, Modules).
• Discuss the different categories of System Calls and how they provide an interface between the process and the OS.
• Explain the Evolution of Operating Systems from serial processing to modern systems.

UNIT II: Process Management and Scheduling

Part A (2 Marks)

• What is a Process Control Block (PCB)? List its components.
• Define Context Switching.
• What are the three requirements for the Critical Section Problem?
• Distinguish between Preemptive and Non-preemptive scheduling.
• Define Semaphores (Binary and Counting).

Part B (13 Marks)

• Explain the various CPU Scheduling Algorithms (FCFS, SJF, Priority, Round Robin) with a numerical example using a Gantt chart.
• Describe the Banker's Algorithm for Deadlock Avoidance with a step-by-step example.
• Discuss the Classical Problems of Synchronization (e.g., Dining Philosophers or Readers-Writers problem).

UNIT III: Memory Management

Part A (2 Marks)

• What is Fragmentation? Differentiate between Internal and External.
• Define Paging and Segmentation.
• What is Demand Paging?
• Define Thrashing. How can it be prevented?
• What is a Translation Look-aside Buffer (TLB)?

Part B (13 Marks)

• Explain the hardware implementation of Paging and Segmentation with neat diagrams.
• Discuss Page Replacement Algorithms (FIFO, Optimal, LRU) with a numerical example.
• Explain Virtual Memory Management and the steps involved in handling a Page Fault.

UNIT IV: Storage Management

Part A (2 Marks)

• What is Disk Scheduling?
• Define RAID and list its basic levels.
• List the different File Access Methods.
• What are the various File Allocation Methods?
• Define a Directory Structure.

Part B (13 Marks)

• Explain the various Disk Scheduling Algorithms (FCFS, SSTF, SCAN, C-SCAN, LOOK) with a numerical problem.
• Describe File System Implementation and the different methods for allocating disk space (Contiguous, Linked, Indexed).
• Discuss Free Space Management techniques (Bit Vector, Linked List, Grouping, Counting).

UNIT V: Virtual Machines and Mobile OS

Part A (2 Marks)

• What is a Hypervisor? Name the two types.
• Define Virtualization.
• List key features of the Android OS.
• What is the role of the Dalvik Virtual Machine (DVM) or ART in Android?
• State the difference between iOS and Android architectures.

Part B (13 Marks)

• Explain the building blocks and implementation of Virtual Machines.
• Describe the Android OS Architecture with a neat block diagram.
• Discuss the iOS Architecture and its core layers (Core OS, Core Services, Media, Cocoa Touch).

Most Repeated / High-Weight Questions

CPU scheduling algorithms with Gantt charts, deadlock avoidance and banker's algorithm, page replacement algorithms, virtual memory management, disk scheduling algorithms, process synchronization problems.