Arca Noae is an OS/2-focused software and development company, providing expert consulting for a wide variety of OS/2 and eComStation installations.

Friend gives you control of your own data, on your own online computer on locally managed servers.

Haiku is an open-source operating system that specifically targets personal computing. Inspired by BeOS, Haiku is fast and easy to learn but very powerful.

ReactOS is a free, opensource reimplementation of windows

FreeDOS is an open source DOS-compatible operating system that you can use to play classic DOS games, run legacy business software, or develop embedded systems.