Category Operating System
Platform(s) IA-32, x64-64, Xbox, ARM
Developer(s) ReactOS Foundation
Source Model Open Source
License GNU Lesser General Public License
Status Alpha
Latest Unstable Version 0.4.6

Early HistoryEdit

Some time in 1996, a group called FreeWin95 was formed with the goal to implement an operating system that would be a free, Open Source clone of Windows 95. Unfortunately, like many such Open Source projects, stylistic differences inhibited FreeWin95's progress and it never accomplished its goal. By the end of 1997, when Windows 98 was released, FreeWin95 had burnt out.

It was around this time that Jason Filby became project coordinator and called on everyone still subscribed to the mailing list to revive the project. It was decided that the new target should be Windows NT, and that there would be an emphasis on results - on written code, rather than endless talk. The project was renamed ReactOS, since the roots of this new OS grew out of a dissatisfaction with Microsoft Corporation's monopoly over the operating system market. In February 1998, ReactOS officially began.


The first few years of ReactOS were painfully slow, despite the large amount of code that was being written. Only a few of the developers knew how to write kernel code. It was a time of only a few people writing the difficult kernel beginnings. Later, as the kernel became more complete and stable, and as basic drivers such as the IDE and Keyboard drivers were written, more people were able to get involved in the development.

Development GoalEdit

The main goal of the ReactOS project is to provide an operating system which is binary compatible with Windows.[1]

Current Status of ReactOSEdit

With the release of 0.4.6, there are many improvements included. ReactOS Loader can now load custom kernels and HALs. A huge number of new APIs were implemented for the printing subsystem. A new shim engine as introduced as part of the new application compatibility framework. Msstyle themes now work almost perfectly. ReactOS is now much more stable now as a result of several memory manager, ntoskrnl and filesystem fixes. User experience has been improved by making several settings properly remember upon restarting ReactOS. NETAPI, the network transport and security library has been implemented. WinSock2 has been reworked.

System RequirementsEdit

Filesystem SupportEdit

ReactOS currently supports FAT12, FAT16, FAT32, VFAT, Ext2, and BTRFS. Work on a NTFS driver also exists, though it is currently not suitable for inclusion.

ReactOS PortsEdit

Various ports of ReactOS exist, that can run on different arcitectures. Listed are the ports currently known.


  1. ReactOS Website