Process vs Thread in Operating System with Examples

Explain the Difference Between Process and Thread in Operating System

In operating systems, two very important concepts are Process and Thread. If you’re learning about OS for the first time, it can be confusing. But don’t worry! In this blog post, we’ll explain the difference between process and thread in very simple words, with examples, code, and step-by-step explanation.

🧠 What is a Process?

A process is an instance of a program that is running. When you open any application on your computer, like Chrome, Word, or VLC, the OS creates a process for it.

🔍 Key Features of a Process:

• It has its own memory.

• It has its own code, data, and resources.

• Google Advertisement

  It is independent from other processes.

• Communication between processes is difficult and slow (called IPC - Inter Process Communication).

💡 Real-life Example:

Think of a process as a house. Each house has its own gate, rooms, and kitchen. It doesn’t share space with another house.

🧵 What is a Thread?

A thread is the smallest unit of execution inside a process. A process can have multiple threads that share the same memory.

🔍 Key Features of a Thread:

• Shares code and memory with other threads in the same process.

• Very lightweight and faster to create.

• Google Advertisement

  Used in multithreading applications to improve performance.

💡 Real-life Example:

If a process is a house, threads are the people living in that house. They share the same kitchen, rooms, and bathroom.

🔄 Difference Between Process and Thread

👨‍💻 Code Example in C

Let’s take a simple example using C to show the difference between process (using fork()) and thread (using pthread).

📁 1. Process using fork()

#include <stdio.h>
#include <unistd.h>

int main() {
    printf("Main process started\n");

    int pid = fork();  // Create a new process

    if (pid == 0) {
        // Child process
        printf("Child Process: PID = %d\n", getpid());
    } else {
        // Parent process
        printf("Parent Process: PID = %d\n", getpid());
    }

    return 0;
}

🧠 Explanation:

• fork() creates a new child process.

• The child process is a copy of the parent process but runs independently.

• Both have their own memory.

📁 2. Thread using pthread

#include <stdio.h>
#include <pthread.h>

void* myThreadFunction(void* arg) {
    printf("Inside thread function\n");
    return NULL;
}

int main() {
    pthread_t thread;

    printf("Main function started\n");

    pthread_create(&thread, NULL, myThreadFunction, NULL);  // Create thread
    pthread_join(thread, NULL);  // Wait for thread to finish

    printf("Thread finished\n");

    return 0;
}

🧠 Explanation:

• Google Advertisement

  pthread_create creates a new thread inside the same process.

• Threads share the same memory, so no duplication happens.

• Communication is easy and fast.

⚙️ When to Use Process vs Thread?

📝 Summary

• Process is a heavy, independent unit with separate memory.

• Thread is a lightweight, shared unit inside a process.

• Threads are faster but less isolated.

• Use processes for safety and isolation; use threads for performance and responsiveness.

📌 Final Words

Understanding the difference between process and thread is important for system programming, OS concepts, and even real-world application development. You’ve now seen both in code and real-world analogies.