Wikipedia
SkyOS
SkyOS (Sky Operating System) was a prototype commercial, proprietary, graphical desktop operating system written for the x86 computer architecture. As of January 30, 2009 development was halted with no plans to resume its development. In August 2013 Robert Szeleney announced the release of a public beta on the SkyOS website. This allows public users to download a Live CD of the SkyOS operating system, for testing and to optionally install the system.