From the website:
FreeDOS is a free DOS-compatible operating system for IBM-PC compatible systems. FreeDOS is made of up many different, separate programs that act as "packages" to the overall FreeDOS Project.What's amazing is that the developers are still hammering on it, adding features (like USB support) and improving it. So while it will likely work quite well on those truly retro relics in your parents' basement, it likely works even better on that Pentium 3 in your own closet.
We welcome new users to FreeDOS. You can contribute to the FreeDOS Project by downloading our latest release and telling us what you think. We have a bug tracking system that helps you report problems and submit requests, and otherwise tell us how to improve FreeDOS. By participating in the development and debugging process, you help everyone.