OnWorks ReactOS online, a free and open-source operating system based on the best design principles found in the Windows NT architecture. Written completely from scratch, ReactOS is not a Linux-based system and it shares none of the UNIX architecture. The main goal of the ReactOS project is to provide an operating system which is binary compatible with Windows. This will allow Windows applications and drivers to run as they would on a Windows system. Additionally, the look and feel of the Windows operating system is used, such that people accustomed to the familiar user interface of Windows would find using ReactOS straightforward. The ultimate goal of ReactOS is to allow people to use it as an alternative to Windows without the need to change software they are used to.
As you can see in OnWorks with ReactOS it has the following main features:
The ReactOS project reimplements a state-of-the-art and open NT-like operating system based on the NT architecture. It comes with a WIN32 subsystem, NT driver compatibility and a handful of useful applications and tools.
ReactOS combines the power and strengths of the NT kernel – which is well known for its extensibility, portability, reliability, robustness, performance and compatibility – with Win32 compatibility.
Recent NT-based operating systems from Redmond, especially XP, got a bad reputation for their weak default security settings; mainly to simplify the transition from Win9x for both users and legacy applications. This decision alone invalidated many of the security features in NT. ReactOS will incorporate proper default security settings. ReactOS has been designed for high security; it doesn't share some of the common security flaws with other operating systems.
ReactOS is designed to be powerful and lightweight. You can think of the term "lightweight" in the good old fashion of Win95, a consistent user interface and small bundle of very common and useful tools. Although lightweight, ReactOS offers a lot in comparison to Windows 95, with an up-to-date experience as well as built from scratch on a rock solid NT core.
The ReactOS operating system design is able to provide portability across families of processors, such as Intel x86 and even provide portability across different processor architectures, such as CISC and RISC. There is only one single OS core, the kernel; porting ReactOS to other architectures only involves porting the hardware abstraction layer, the lowest part that talks directly with the platform hardware.
ReactOS is flexible and extensible by design. ReactOS is probably one of the most versatile operating system platform, especially thanks to its NT kernel and the open source nature. ReactOS can be extended with the help of so called "subsystems" to provide support for legacy applications from other platforms. For example, a POSIX subsystem would provide compatibility layer with various flavors of UNIX applications.