Process Management: Multitasking, Scheduling, Threads vs Processes

Process Management in OS🕒:

 Handles the execution of programs and manages the CPU.

1. Multitasking 🖥️

Multitasking refers to the ability of an OS to run multiple tasks simultaneously. It's like juggling multiple things at once! 💪

• Preemptive Multitasking: The OS can interrupt a process and switch to another. ⏱️
• Cooperative Multitasking: Processes must give control back to the OS to switch. 🔄

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2. Processes vs Threads 🔄

• Process:
  A process is an independent program with its own resources. Think of it as a full-blown application! 💻

• Thread:
  A thread is a smaller unit of execution within a process. Multiple threads share the same resources, making them faster but riskier! ⚡

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3. Process Scheduling 🗓️

The OS uses scheduling algorithms to decide which process gets CPU time. 🕒

• Round Robin: Processes are given a fixed time slice.
• FCFS: First process in gets executed first.
• Priority Scheduling: The highest priority process runs first. 🚀

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Hands-on: Process & Thread Management 💡

Linux (Bash) 🐧

Viewing Processes:

bash

ps aux  # See all running processes
pstree  # View processes in a tree structure 🌳

Creating a Process:

bash

sleep 60  # This creates a process that waits for 60 seconds ⏳

Viewing Threads:

bash

ps -T -p 1234  # List threads of a process with PID 1234 🧵

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Windows (PowerShell) 💻

Viewing Processes:

powershell

Get-Process  # List all processes 📋

Creating a Process:

powershell

Start-Process "notepad.exe"  # Open Notepad as a new process 📝

Creating Threads (via .NET in PowerShell) 💻:

powershell

Add-Type -TypeDefinition @"
using System;
using System.Threading;
public class ThreadExample {
    public static void PrintMessage() {
        Console.WriteLine("Hello from Thread!");
    }
}
"@
$thread = [System.Threading.Thread]::new([ThreadExample]::PrintMessage)
$thread.Start()  # Start a new thread 🧵

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4. Thread vs Process Handling ⚖️

• Memory: Threads share memory, processes don't. 🧠 vs 🧱
• Creation Time: Threads are quicker to create since they share resources. ⚡
• Context Switching: Switching between threads is faster than processes. 🚦

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5. Advanced: Process Synchronization 🔒

When multiple threads/processes share resources, we need mutexes and semaphores to avoid chaos. 🛑

• Mutex: Ensures only one thread can access a resource at a time. 🚷
• Semaphore: Allows multiple threads to access a resource, but with limits. ⛔

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Summary 📚:

• Processes: Independent units of execution. 🏃‍♂️
• Threads: Lighter units that share resources. 🧵
• Multitasking: Managing multiple tasks at the same time. 🏃‍♀️💨
• Scheduling: Decides which process runs when. ⏲️