ReactOS is an open source project to develop a microkernel based operating system that is compatible with Windows NT and Windows 2000 applications and drivers. The project is currently in the alpha development stage. ReactOS is licensed under the GNU GPL.
History
Around 1996, a group of open source developers started a project called FreeWin95, with the aim of implementing an operating system that would be a clone of Windows 95. The project stalled in discussions of the design of the system.
At the end of 1997, the project still had no results. The project members called to revive the project, the project's target was changed to Windows NT and the project's name was changed to ReactOS. The ReactOS project began in February 1998, with developing the kernel and basic drivers.
Functionality
As of 2004, the ReactOS kernel is quite stable, many APIs are ready for a higher level of development and a basic GUI is available. ReactOS features ReactOS Explorer, which is a basic shell for ReactOS, similar to Windows Explorer.
Version 0.2 of ReactOS is able to run many Win32 applications, including Notepad (a basic text editor), Regedit (the registry editor), Cmd (the commander interpreter) and several other applications and basic games.
As of version 0.2.4, sound support is functional for some cards, and networking code is moving ahead. Screenshots of lynx grabbing a page have been demonstrated, although this still needs some work. Ext2 FS support was also added, allowing Reactos to co-exist with Linux partitions.
Related projects
ReactOS works with the Wine project so that the ReactOS project can benefit from Wine's progress in implementing the Win32 API. These efforts mainly concern Wine's DLLs, most of which can be shared between ReactOS and Wine. Both projects work on cross-compatibility issues, so that the remaining few DLLs can be used in ReactOS.
Future
ReactOS developers are working on improving the GUI system, adding networking, multimedia, and PnP hardware support. Java support and compatibility with DOS and OS/2 are also important subsystems that need to be worked on.