Operating Systems Notes: All UNITS

UNIT – 1

1. Introduction to Operating Systems

• Definition and Purpose: Understanding what an operating system (OS) is and its role in a computer system.
• History and Evolution: Brief history of operating systems, from batch processing systems to modern OS.
• Types of Operating Systems: Batch, time-sharing, distributed, real-time, and mobile operating systems.

UNIT – 2

2. System Structures

• System Components: Hardware, system programs, application programs.
• Operating System Services: Functions and services provided by the OS.
• System Calls: Interface between the OS and user programs.
• System Programs: Programs that provide a convenient environment for program development and execution.

UNIT – 3

3. Process Management

• Process Concepts: Definition, process states, process control block (PCB).
• Process Scheduling: Scheduling criteria, types of schedulers (long-term, short-term, medium-term), context switching.
• Operations on Processes: Process creation, termination, inter-process communication (IPC).
• Threads: Concept, benefits, multithreading models.

UNIT – 4

4. CPU Scheduling

• Basic Concepts: CPU-I/O burst cycle, CPU scheduler, preemptive vs. non-preemptive scheduling.
• Scheduling Algorithms: First-Come, First-Served (FCFS), Shortest Job Next (SJN), Round Robin (RR), Priority Scheduling, Multilevel Queue Scheduling.
• Evaluation of Scheduling Algorithms: Throughput, turnaround time, waiting time, response time.

UNIT – 5

5. Synchronization

• The Critical-Section Problem: Solution requirements, mutual exclusion.
• Synchronization Hardware: Mechanisms to achieve process synchronization.
• Semaphores: Definition, operations, and implementation.
• Classical Problems of Synchronization: Producer-Consumer problem, Readers-Writers problem, Dining Philosophers problem.
• Monitors: High-level synchronization construct.

UNIT – 6

6. Deadlocks

• System Model: Resource allocation graph.
• Deadlock Characterization: Necessary conditions, resource allocation graph.
• Deadlock Prevention: Ensuring at least one of the necessary conditions cannot hold.
• Deadlock Avoidance: Banker’s algorithm.
• Deadlock Detection and Recovery: Methods to detect and recover from deadlocks.

UNIT – 7

7. Memory Management

• Basic Concepts: Logical vs. physical address space, memory allocation.
• Swapping: Concept and implementation.
• Contiguous Allocation: Fixed and dynamic partitioning, fragmentation.
• Paging: Basic concept, page table, hardware support.
• Segmentation: Basic concept, segment table.

UNIT – 8

8. Virtual Memory

• Demand Paging: Concept, page replacement algorithms (FIFO, Optimal, LRU).
• Thrashing: Cause and control.
• Page Replacement: Algorithms and performance comparison.
• Memory-Mapped Files: Concept and usage.

UNIT – 9

9. File Systems

• File Concept: File attributes, operations, types.
• Access Methods: Sequential, direct, indexed.
• Directory Structure: Single-level, two-level, tree-structured, acyclic-graph, general graph.
• File-System Mounting: Concept and implementation.
• File Sharing: Methods and issues.
• Protection: Access control mechanisms.

UNIT – 10

10. Secondary Storage Management

• Disk Structure: Physical structure of disks, disk scheduling algorithms (FCFS, SSTF, SCAN, C-SCAN).
• Disk Management: Disk formatting, boot block, bad blocks.
• RAID: Levels and implementation.

UNIT – 11

11. I/O Systems

• I/O Hardware: Devices, controllers.
• I/O Software: Goals of the I/O software.
• I/O Operations: Polling, interrupts, DMA.
• Drivers: Device driver functions and implementation.

UNIT – 12

12. Security and Protection

• Goals of Protection: Ensuring only authorized access.
• Access Control: Access matrix, access control lists, capabilities.
• Security Problems: Threats, intrusions, viruses, worms.
• Cryptography: Basics of encryption and decryption.

Recommended Books and Resources

• “Operating System Concepts” by Abraham Silberschatz, Peter B. Galvin, and Greg Gagne: Comprehensive coverage of OS concepts.
• “Modern Operating Systems” by Andrew S. Tanenbaum: Detailed exploration of modern operating systems.
• “Operating Systems: Internals and Design Principles” by William Stallings: In-depth look at OS design and internals.
• Online Resources: MOOCs on platforms like Coursera, edX, and Khan Academy.

Practical Assignments

• Process and Thread Management: Writing programs to create and manage processes and threads.
• CPU Scheduling Simulation: Implementing and comparing different CPU scheduling algorithms.
• Memory Management Simulation: Implementing paging, segmentation, and virtual memory concepts.
• File System Simulation: Creating and managing a simple file system.
• Synchronization and Deadlocks: Implementing synchronization techniques and deadlock handling methods.
• I/O Management: Writing drivers for simulated hardware.

Practical Skills

• System Programming: Writing and understanding system-level programs.
• Problem-Solving: Applying OS concepts to solve practical problems.
• Debugging: Techniques for debugging complex OS-related programs.
• Simulation and Modeling: Creating simulations to model OS behavior and performance.