Fusion OS is a Open Source Operating System, mainly licensed under the MPL 1.1. Parts of it are licensed upder the GNU GPL or other open source licenses. Fusion OS is based on the ReactOS project, and we contribute any bugs found in ReactOS back to them
GeekOS is an tiny operating system kernel which runs on bare x86 PC hardware
The Vortex project consists of 2 things. The Vortex OS and VParse. The OS is multitasking and handles a lot of features. VParse is a stand alone Vertex2 parser. Vertex is vortex's scripting language. Pre 0.7 is QBasic and 0.7 is C++.
FreeOS/1 is a Free, Open Source, FreeDOS based Free and Open Source Alternative OS, with open source Microsoft Windows compatibility using HXDOSExtender KernelEx,and ReactOS source code. FreeOS/1 will include new technologies and will be easy to use
MOOnix is a UNIX-like internet TCP/IP "OS" written in MOO. MOOnix will allow for active programming, which will allow multiple programmer's clients to automaticly update the source when there is a change. Other users can simple use MOOnix as a UNIX shell.