Threads and Processes in Operating Systems.pptx
- 1. Threads and Processes in Operating Systems
- 2. Introduction to Operating Systems ● An operating system (OS) is system software that manages computer hardware and software resources ● Key functions of an OS: - Process Management - Memory Management - File System Management - I/O Management ● Modern OS examples: Windows, Linux, macOS, Android, iOS
- 3. What is a Process? ● A process is an independent program in execution ● Each process has its own: - Memory space (Code, Data, Stack, Heap) - CPU registers - Process Control Block (PCB) - I/O resources ● Examples: Web browser, text editor, music player ● Processes communicate through Inter-Process Communication (IPC) mechanisms
- 4. Process States ● New: Process is being created ● Ready: Process is waiting to be assigned to a processor ● Running: Instructions are being executed ● Waiting/Blocked: Process is waiting for some event to occur ● Terminated: Process has finished execution
- 5. Process Control Block (PCB) ● PCB is a data structure maintained by the OS for each process ● Contains all information needed to manage the process: - Process ID (PID) - Process State - Program Counter - CPU Registers - Memory Management Information
- 6. What is a Thread? ● A thread is a lightweight execution unit within a process ● Threads share memory and resources with other threads in the same process ● Enables concurrent execution within a process
- 7. Thread Attributes - Thread ID: Unique identifier for each thread. - Program Counter: Tracks the next instruction. - Register Set: Stores working variables.
- 8. Example usage of threads Output: This example demonstrates: 1.Creation of two threads using pthread_create() 2.Each thread executes the print_message function with a different argument 3.The main thread waits for both threads to complete using pthread_join() 4.Threads share the same code but have different execution paths
- 9. Process vs Thread Aspect Process Thread Definition Independent program in execution Lightweight execution unit within a process Memory Separate memory space Shared memory space Communication Inter-Process Communication (IPC) Direct through shared memory Creation Overhead High Low Context Switch Expensive Less expensive
- 10. Multi-threading: Benefits and Applications Benefits of Multi-threading: - Improved responsiveness - Resource sharing - Economy (less overhead than multiple processes) - Scalability (better utilization of multiprocessor architectures)
- 11. Types of Threads ● User-Level Threads: - Managed by user libraries - Faster but blocks entire process ● Kernel-Level Threads: - Managed by OS kernel - Slower but more robust
- 12. User-Level Threads Implemented by user-level thread libraries ● Advantages: - Fast thread switching - Can be implemented on any OS ● Disadvantages: - Entire process blocks if one thread makes a blocking system call
- 13. Kernel-Level Threads Implemented and managed by the OS kernel ● Advantages: - Can utilize multiprocessor architectures - If one thread blocks, others can still run ● Disadvantages: - Higher overhead for thread management
- 14. Thread Implementation Examples ● POSIX Threads (Pthreads): - Standard API for creating and manipulating threads ● Java Threads: - Built into Java language ● Windows Threads: - Part of the Win32 API
- 15. Practical Applications ● Web Browsers: - Separate threads for rendering, JavaScript execution, network I/O ● Server Applications: - Thread pool for handling multiple client connections ● Mobile Applications: - Background threads for data synchronization ● Video Editing Software: - Parallel processing of video frames
- 16. Thank You! A Anshul Rao 23B81A05D6