Frequently Asked Questions

Frequently Asked Questions

Frequently Asked Questions (FAQ) about ReactOS. If you have more detail questions and/or search for technical answers, read the Developer FAQ.

What is ReactOS?
Is ReactOS based on Microsoft® Windows®?
Is ReactOS based on *nix or Linux?
Is ReactOS legal?
Why isn't NTFS supported in ReactOS?
The ReactOS GUI sucks! Why don't you use another shell?
Why does a certain application of mine not work under ReactOS?
Why ReactOS? Why clone Microsoft Windows?
Why don't you help develop Wine/Linux instead?
On which processors will ReactOS run?
Where can I download ReactOS?
How can I contribute to ReactOS?
When will ReactOS be done?
I want to test ReactOS without risking my existing hardware/installations. Can I test ReactOS another way?
Why not let my employer host your site for free?
I can not login. It says that I am already logged in.

What is ReactOS?

ReactOS (short for React Operating System) is an open-source effort to develop a quality operating system that is compatible with Microsoft Windows applications and drivers. [more]

Is ReactOS based on Microsoft® Windows®?

No! ReactOS consists only of GNU GPL (General Public License) and GPL compatible licensed source code.

Is ReactOS based on *nix or Linux?

No! ReactOS is not based on UNIX/Linux. It's written from scratch.

Is ReactOS legal?

Yes. It's fully legal.

Developers have not looked at Windows® source code. They have used the public documentation of Windows® OSes. They have made several tests to understand how Windows® works. In fact, ReactOS does the same things Windows® does, but not exactly in the same way, because they haven't the same source code. All code in ReactOS is under the GNU GPL (General Public License).

Why isn't NTFS supported in ReactOS?

NTFS is very hard to implement. The only implementation that is near-complete is NTFS-3g (FUSE), which is not kernel-level.

Reasons are:

NTFS is a very complex filesystem.
It's not documented. For this reason it is more difficult to create an implementation. It doesn't assure full compatibility with Windows® in unusual circumstances nor with future versions of Windows®.

You can find exhaustive discussions in ReactOS Forum for further details.

NTFS may be implemented in future development stages of ReactOS. Please wait patiently.

The ReactOS GUI sucks! Why don't you use another shell?

When ReactOS is more complete you will be free to use any other alternative shell. But we need a Explorer like shell, to be fully compatible. Your moaning won't change anything...

Why does a certain application of mine not work under ReactOS?

ReactOS is in alpha stage and not recommended for everyday use. Many applications do not work (correctly) because many API calls simply haven't been implemented yet. This may be one of the reasons for the software not working.

Why ReactOS? Why clone Microsoft Windows?

First of all, ReactOS is not a clone of Windows. ReactOS is an operating system that is compatible with Microsoft Windows applications and drivers. Some of the reasons are the same as the reasons for developing Linux (an open-source UNIX clone)? In short, Linux is a great operating system, but it is not the answer for everybody. There are a lot of people that like Microsoft Windows, but are very frustrated with Microsoft's policies on various issues.

The 9x family of Microsoft Windows is based on DOS, and shares many of its weaknesses, which is the primary reason why Microsoft Windows has such a bad name. The Microsoft Windows NT family of Windows, however, has a solid design. Not everything is perfect, but without access to the source code, there is no way to fix it, so a compatible operating system must be built from the ground up.

Why don't you help develop Wine/Linux instead?

This is a very common FAQ, so it's placed in User FAQ also (and technical answer is given in Developer FAQ).

ReactOS works very closely with Wine, and thus both projects actually benefit from each other. We have several developers in both the WINE and ReactOS projects that work on cross-compatibility issues between the two projects.

It is our view that Linux + Wine can never be a full replacement for Microsoft(R) Windows(R). ReactOS has the potential for a much higher degree of compatibility - especially for Microsoft(R) Windows(R) drivers - which WINE does not address.

On which processors will ReactOS run?

ReactOS currently only supports the x86 processor architecture, although a PowerPC and AMD port has begun. ReactOS will run on Intel(R) Pentium(R) x64, Intel Xeon(R) x64, AMD(R) Athlon(R) x64 and AMD Opteron(R) processors in 32-bit mode, but the 64-bit functionality of these processors is not currently supported. See Compatibility Database for a list of supported device drivers.

Where can I download ReactOS?

Please visit the download page.

How can I contribute to ReactOS?

Please visit the contribute to ReactOS page.

When will ReactOS be done?

First you need to define what ReactOS should be capable of when it is to be considered done. Since this definition may vary greatly between people, this question cannot be completely answered. One thing is for sure: ReactOS will continue to be developed, as there will always be a need for improvements. For more information, visit the Roadmap page.

I want to test ReactOS without risking my existing hardware/installations. Can I test ReactOS another way?

Yes, you can test ReactOS on virtual hardware. You can test it in Qemu, for which there are official packages available on the download page. This way, you can start ReactOS in a window without leaving your operating system. However, because Qemu is an emulator, ReactOS will run much slower than it would if it were running on actual hardware. Other virtual machines/x86 emulators should be able to run ReactOS as well, and ReactOS is known to run in at least Bochs, VMWare, VirtualPC and QEMU. If you know of other virtual machines that support it, please send an e-mail to the ros-dev mailing list.

Why not let my employer host your site for free?

Thanks for the offer, but no, thanks. Things may change within your organization and then we'd be either politely asked to start paying X amount or go elsewhere. With our current setup, we have direct access to the machine, bandwidth is not a problem, although the hardware does need improvement (if you wish to donate hardware for this cause, contact one of the ReactOS coordinators).

I can not login. It says that I am already logged in.

This problem is being worked on. However, as a workaround to login again, you can use the "Did you forget your Password?" link and change your password; your old sesion will be deleted and you can login again using the new password. After that, remember to change the "multisession" option in your profile, which will allow you to login multiple times.