C# Open Source Managed Operating System

"May the source be with you"

Cosmos is an operating system "construction kit", built from the ground up around the IL2CPU compiler in C# and our home-brewed X#.

CodePlex has a limitation on embedded video, so click our link to see:

Supporting Cosmos

Anyone can support Cosmos! Even if you can't program, you can support us. Please make a donation to help us out!

Donate via PayPal

Cosmos in Action

Source Code in VS2013 - Light Theme.png

And you can even debug:
Debugging in VS2013 - Light Theme.png


Cosmos in its current stage is only usable for academic work. Some day Cosmos will be ready for production work, but to reach that stage we need more developers. Specifically, we need a few more low level developers to help the few core developers who are currently overwhelmed with work.


Cosmos is available in two forms:
  • User Kit - User Kit allows you to develop your own custom operating system in Visual Studio. If you are new to Cosmos, start here.
  • Dev Kit - Dev Kit is the full Cosmos source with build tools. If you need to modify core Cosmos functions or modify built in drivers, boot, compiler, etc then you will need to use Dev Kit.

Getting Started

Joining Cosmos

  • Yahoo Group - Email Discussion List. To prevent spambots from spamming our list we ask you introduce yourself to join. Please mention something specific to Cosmos. "Hey I want to join" won't get you in....
  • Cosmos Chat Room - Live chat. When joining give some time for response. Asking a question and leaving a few minutes or seconds later will not give anyone any time to notice your presence.
  • Facebook - Like us to see frequent updates of what is going on with Cosmos.
  • YouTube Channel - Follow use to see useful videos.
  • Resources - More Cosmos related links.

Articles and Resources



We encourage you to add your own Cosmos videos to YouTube. Please add the tags Cosmos and C# when uploading.

Last edited Sep 10 at 6:01 PM by kudzu, version 125