ReactOS [http://www.reactos.org/] is a [GPL] 2 license operating system that aims to replace Microsoft [Windows XP]. Internally, it makes use of [Wine] libraries. Externally, it has a general look and UI similar to Windows XP in "classic" mode. ---- [peterc] 2008-06-10: While general system stability is a serious issue in version 0.3.4, my [starpack] applications ran on it without any serious problems, apart from some alpha transparency issues with some [PNG] icons in [Tile] buttons. It's promising in that by the time it is a stable platform in a couple of years (say, in 2010), it will be in competition with [Windows 7] without MinWin to stem the Vista bloat. ReactOS may be an easier sell to IT departments at this time than official [Microsoft Windows]. ---- [peterc] 2008-06-13: [getWindowsAPIVendor] is a small but handy proc for detecting which win32 code base your app is really running on: [Wine], ReactOS or [Microsoft Windows]. This can be used for tuning your app or informing the user of support/non-support. ---- Looking at the web site, the effort is currently working on version 0.3.13. It has gone through 0.0.8 releases in 3 years. [AMG]: I have to give them credit for posting Cave Story screen shots. ;^) Though, the font rendering is quite funky: http://www.reactos.org/media/screenshots//2009/ros_039_cave_story.png. (Dear Wikignomes: please fix the preceding link to show up as [[1]] or similar, without being displayed inline.) [peterc] 2017-09-04: The project's still going and actively developed. They've recently released [https://www.reactos.org/project-news/reactos-046-released] v0.4.6, and it doesn't look too bad. <> Operating System