Multi-Algorithm CPU Scheduler Simulator

A comprehensive CPU scheduling algorithm simulator with both Web GUI (React) and CLI interfaces. This project implements and visualizes multiple scheduling algorithms with interactive Gantt charts and automated metrics calculation.

🎯 Features

Scheduling Algorithms Implemented

1. FCFS - First Come First Serve
2. SJF - Shortest Job First (Non-preemptive)
3. SRTF - Shortest Remaining Time First (Preemptive SJF)
4. RR - Round Robin (configurable time quantum)
5. Priority - Priority Scheduling (preemptive and non-preemptive)
6. MLQ - Multi-Level Queue
7. MLFQ - Multi-Level Feedback Queue

Key Features

• 📊 Interactive Gantt Charts - Visual timeline of process execution
• 📈 Automated Metrics - Average waiting time, turnaround time, CPU utilization
• 🌐 Web GUI - Beautiful, responsive React-based interface
• 💻 CLI Interface - Command-line tool for automation and scripting
• ⚙️ Configurable Parameters - Time quantum, priorities, queue levels
• 📱 Responsive Design - Works on desktop, tablet, and mobile

🚀 Quick Start

Prerequisites

• Python 3.8 or higher
• Node.js 14 or higher
• npm or yarn

Installation

Backend Setup

cd backend
pip install -r requirements.txt

Frontend Setup

cd frontend
npm install

💻 Usage

Web GUI

1. Start the Backend Server:

cd backend
python api.py

The API server will start at http://localhost:5000

2. Start the Frontend Development Server:

cd frontend
npm start

The web interface will open at http://localhost:3000

3. Use the Interface:
   • Add processes with their arrival time, burst time, priority, and queue level
   • Select a scheduling algorithm
   • Configure algorithm-specific parameters (time quantum, preemptive mode, etc.)
   • Click "Run Simulation" to see the Gantt chart and metrics

CLI Interface

Run simulations from the command line:

cd backend
python cli.py --algorithm <algorithm> --processes '<json_data>'

CLI Examples

FCFS:

python cli.py --algorithm fcfs --processes '[{"pid":1,"arrival_time":0,"burst_time":4},{"pid":2,"arrival_time":1,"burst_time":3}]'

Round Robin with Time Quantum 3:

python cli.py --algorithm rr --time-quantum 3 --processes '[{"pid":1,"arrival_time":0,"burst_time":5},{"pid":2,"arrival_time":2,"burst_time":3}]'

Priority Scheduling (Non-preemptive):

python cli.py --algorithm priority --processes '[{"pid":1,"arrival_time":0,"burst_time":4,"priority":2},{"pid":2,"arrival_time":1,"burst_time":3,"priority":1}]'

Priority Scheduling (Preemptive):

python cli.py --algorithm priority --preemptive --processes '[{"pid":1,"arrival_time":0,"burst_time":4,"priority":2},{"pid":2,"arrival_time":1,"burst_time":3,"priority":1}]'

Using a JSON file:

python cli.py --algorithm sjf --file processes.json

MLFQ with custom time quantums:

python cli.py --algorithm mlfq --time-quantums "[2,4,8]" --processes '[{"pid":1,"arrival_time":0,"burst_time":10}]'

📊 Metrics Calculated

The simulator automatically calculates:

• Average Waiting Time - Average time processes wait in ready queue
• Average Turnaround Time - Average time from arrival to completion
• CPU Utilization - Percentage of time CPU is actively executing processes
• Individual Process Metrics - Waiting time, turnaround time, response time per process

🏗️ Project Structure

Multi-Algorithm-Scheduler-Simulator/
├── backend/
│   ├── scheduler.py       # Core scheduling algorithms implementation
│   ├── api.py            # Flask REST API server
│   ├── cli.py            # Command-line interface
│   └── requirements.txt  # Python dependencies
├── frontend/
│   ├── public/
│   │   └── index.html    # HTML template
│   ├── src/
│   │   ├── components/   # React components
│   │   │   ├── GanttChart.js
│   │   │   ├── Metrics.js
│   │   │   └── ProcessInput.js
│   │   ├── utils/        # Utility functions
│   │   │   └── api.js
│   │   ├── styles/       # CSS stylesheets
│   │   │   └── App.css
│   │   ├── App.js        # Main React component
│   │   └── index.js      # React entry point
│   └── package.json      # Node.js dependencies
└── README.md             # This file

🎓 Concepts Covered

CPU Scheduling

• Non-preemptive vs Preemptive scheduling
• Context switching
• Process states and transitions
• Scheduling criteria (CPU utilization, throughput, waiting time, etc.)

Data Structures

• Process Control Block (PCB)
• Ready queues
• Multi-level queues
• Priority queues

Simulation

• Discrete event simulation
• Gantt chart generation
• Performance metrics calculation

🔧 Configuration

Time Quantum (Round Robin)

Adjustable via GUI slider or --time-quantum CLI flag. Default: 2

Priority Levels

Lower numbers indicate higher priority. Range: 0-∞

Queue Levels (MLQ/MLFQ)

Queue 0 = highest priority. Configure time quantums per queue.

📱 Screenshots

The web interface features:

• Clean, modern design with gradient backgrounds
• Interactive process input forms
• Real-time Gantt chart visualization
• Color-coded process blocks
• Metric cards with key performance indicators

🤝 Contributing

This is an educational project. Feel free to:

• Add more scheduling algorithms
• Improve the UI/UX
• Add more metrics
• Enhance visualizations
• Add unit tests

📝 License

This project is for educational purposes as part of an Operating Systems course.

👨‍💻 Author

OS Project - Multi-Algorithm Scheduler Simulator

🙏 Acknowledgments

• Operating Systems concepts and algorithms
• React and Flask frameworks
• CPU scheduling theory and implementation