RTOS Scheduler Simulator

What is this? This simulator visualizes how different Real-Time Operating System (RTOS) scheduling algorithms prioritize and execute tasks over time. Add your custom tasks below, select a scheduling algorithm, and run the simulation to generate an interactive chart.

Supported Algorithms

  • EDF (Earliest Deadline First): Dynamic priority. The scheduler always chooses the ready task with the closest absolute deadline. Preemptive.
  • RM (Rate Monotonic): Static priority. Tasks with shorter periods are assigned higher priority. It is optimal for periodic tasks. Preemptive.
  • FCFS (First Come First Serve): Non-preemptive. The scheduler simply executes tasks in the exact order they arrive, ignoring deadlines and periods.

Add Task

Task List

TaskCAPDAction

How to Read the Chart

Visual Key:

Normal Execution
Late Execution (Past Deadline)
⚫ Task Completed (Finish Line)
↓ Task Arrival
↑ Deadline

Disclaimers and Simulation Notes

Use it at your own risk, scheduling algorithms and visualizations may be wrong.
  • Overhead: Context switching and scheduling computation time are assumed to be zero.
  • Time Limit: The simulation automatically calculates 1 Hyperperiod (the Least Common Multiple of all periodic tasks) and stops there. To prevent browser freezing on complex inputs, the timeline is strictly capped at 200 ticks.
  • Defaults: If a deadline is left blank for a periodic task, the simulation automatically assumes the relative deadline is equal to the period.
Built for educational RTOS visualization by Sandrini Mattia.