Building a binary-compatible Windows distribution is a daunting prospect. Various volunteers have been working on ReactOS, a project that has been working toward that goal since the first public release in 2004.

In a 2008 blog post on developing Windows 7, Steven Sinofsky notes that about 25 teams of roughly 40 members each were responsible for development of that OS, yet the ReactOS team has only 26 developers working directly on this new release. However, there are roughly 200 developers involved with sub-projects and components designed for ReactOS, but that have a use outside of the project.

What exactly is ReactOS?

ReactOS is a free and open source implementation of the Windows NT architecture, which intends to provide support for existing applications and drivers, outside of the control of Microsoft.

Much like Linux distributions, the ReactOS team is responsible for integrating a variety of libraries together to create a working OS image. As a result, the ReactOS team is not responsible for recreating every core function of Windows–the TCP/IP stack is provided by lwIP, fonts are handled by freetype, and various other libraries like libjpeg, libpng, and zlib (among others) are provided by upstream projects which are also incorporated in various Linux distributions. Accordingly, support for Win32 programs is provided through WINE, with the kernel and other low-level utilities written by the ReactOS team.

It is worth noting that ReactOS is a substantially smaller and lightweight OS than Windows. At less than 150 MB, the install image is really quite tiny. For comparison, the minimum system requirements of Windows 10 require 16GB for installation. Owing to the fact that ReactOS is designed around the idea of being able to use your favorite Windows programs, there are no equivalents to bundled Windows programs like Windows Media Player–VLC installs and works perfectly. That program, and other open source software such as LibreOffice and Inkscape are tested for compatibility and can be installed using the ReactOS Applications Manager.

What’s new in ReactOS 0.4?

The release of ReactOS 0.4 brings improved file system support, including native, out-of-the-box support for ext2, ext3, and ext4, as well as read-only support for NTFS.

Additionally, the bundled version of UniATA was updated to add better support for SATA and PATA devices. Support was generally improved for third-party device drivers, making it substantially easier to install and use real hardware, as opposed to just virtual machines like VirtualBox.

The internal WINE library was updated to improve support for Win32 programs. Support for Python 2.7 was added, making it possible to use python scripts in ReactOS. A substantial number of visual changes were added, with a vastly improved shell and file explorer, newer icons throughout ReactOS, improved support for fonts, and customizable visual themes.

Even with these improvements, ReactOS 0.4 is still generally considered alpha-level software, though Alexander Rechitskiy, community and media relations manager for ReactOS, noted that 0.4.1 may feel like almost beta-level software, though the 0.4.x branch will retain Alpha status.

Why support ReactOS?

ReactOS is essentially a volunteer project. Like many open source projects, it depends on community support. The project advertises itself as being Windows, but with “no government controls, corporate snooping, or privacy backdoors built in.” This is an important consideration relative to the reception of Windows 10, and the controversy surrounding default settings violating user privacy. Speed is also a consideration, as the Linter DBMS was tested to be 10-15% faster on ReactOS than Windows XP on the same hardware.

Of note, the Russian government has selected (link in Russian, translated here) ReactOS as part of an ongoing plan to replace the use of closed-source software with domestic and open source solutions.

The promise of ReactOS is really in hardware and software compatibility, particularly with nonstandard hardware such as ROM burners, development kits, and custom disk flashers for integrated system deployments built around the expectation of using 32-bit Windows for management software. Using discontinued versions of Windows is less of a serviceable solution, as allowing a Windows 2000 machine access to the Internet is a massive security hazard. ReactOS aims to provide compatibility for vendor-supplied drivers with security patches to guard against modern attacks.

What’s your view?

Do you have concerns regarding Microsoft’s changing policies toward user privacy and security with Windows 10? Do you have hardware that has hard dependencies on legacy versions of Windows? Share your thoughts in the comments.