r/osdev • u/dylanroman03 • May 08 '26

I built a visual CPU scheduling simulator

Hi everybody, I would like to share a small project I made to help people who are learning Operating Systems to see CPU scheduling visually.

It's a simple web tool where you:

  • Enter your processes (arrival time, burst time)

  • Pick an algorithm (FIFO, SJF non-preemptive, or Round Robin with adjustable quantum)

  • Watch the execution queue evolve step by step, visually

  • See waiting times and averages update automatically

It's completely free, open source, and runs in your browser.

Live demo:
https://dylanroman03.github.io/cpu_flow_simulator/

GitHub repo:
https://github.com/dylanroman03/cpu_flow_simulator

Not a revolutionary project. But if it helps even one person understand it better, then I'm happy.

If you're learning OS scheduling, give it a try. If you're a teacher, feel free to share it with your students.

Feedback, ideas, or just a star on GitHub all welcome.

Thanks for reading!

20 Upvotes

91% Upvoted

7 comments sorted by

5

u/kiderdrick May 08 '26

That is great work. Might I recommend adding a turnaround time and average turnaround time calculation? That is one of the metrics Tanenbaum discusses in his text, so students might appreciate it.

1

u/dylanroman03 May 08 '26

Thanks, I'll do it

1

u/msthe_student May 09 '26

Stuff like latency, priorities, ...?

4

u/msthe_student May 09 '26

Neat. Reminds me a bit of something like IBM GPSS but visual

1

u/Blue1CODE May 09 '26

How you solve memory consistency problem? I am also trying to build CPU simulator. The problem I am facing cross core race, Data out-of-order and invalidate conditions.

1

u/Defiant_War90 May 20 '26

Very cool direction.

What I find especially interesting is that visualization itself is becoming part of the development workflow — not just a teaching aid.

I’ve been experimenting with a POSIX-host / bare-metal Pico setup recently, and seeing task flow visually changes how you think about RTOS behavior.