ReactOS

ReactOS is a free and open-source operating system project designed to provide binary compatibility with applications and device drivers written for Windows NT-derived systems. It targets personal computers using the x86 and AMD64 architectures and seeks to reproduce the behavior of core Windows interfaces without using proprietary Microsoft source code. The project is positioned as a possible open-source alternative for users who need to run software designed for Windows, although it remains incomplete and is intended primarily for evaluation, experimentation, and testing rather than general production deployment. The project grew out of FreeWin95, an earlier community effort launched around 1996 to create a free implementation of Windows 95. That effort did not produce a public release and eventually stalled over architectural disagreements. In 1998, contributors reorganized around a new objective: implementing an operating system compatible with the Windows NT family. The name ReactOS was adopted during an Internet Relay Chat discussion. The “OS” suffix refers to operating system, while “React” expressed the developers’ reaction against the dominance of proprietary operating systems. ReactOS includes an NT-like kernel, user-mode components, a Win32-compatible API, a registry, a graphical desktop, system utilities, networking, storage support, and a collection of bundled applications. Its desktop includes ReactOS Explorer, an applications manager, a command prompt, Notepad, Paint, WordPad, Task Manager, Device Manager, Event Viewer, a service manager, multimedia tools, and simple games. Compatibility varies by release and application. Some older Windows programs, including versions of Adobe Reader, GIMP, and LibreOffice, have been reported to run, but hardware and software support is not equivalent to that of mature commercial Windows releases. The codebase is primarily written in C, with selected components written in C++, including parts of the file manager and sound stack. ReactOS uses and adapts work from the wider free-software ecosystem, including Wine-related components, Mesa 3D, networking code derived from FreeBSD-related work, and other driver and library projects. The project has also contributed to or interacted with open-source development tooling and has participated in Google Summer of Code. ReactOS is developed by a distributed volunteer and contributor community. A German association, ReactOS Deutschland e.V., has been used in fundraising and organizational activities, while an earlier Russia-based ReactOS Foundation was established in Moscow and later dissolved. The project has conducted donations and crowdfunding campaigns for development, hardware and software support, and proposed cloud-based services. These efforts have supported community work but have not transformed ReactOS into a conventional commercial software company. Its continuing identity is that of an open-source operating-system project whose principal value lies in compatibility research, software freedom, and experimentation with Windows-compatible system architecture.

ReactOS originated in the mid-1990s as FreeWin95, an attempt by free-software developers to create a Windows 95-compatible operating system. The initiative failed to deliver a public build and became bogged down in debates about system design. Around the end of 1997, contributors regrouped under coordinator Jason Filby and redirected the project toward compatibility with Windows NT rather than Windows 95. Development of the new project began in February 1998, initially concentrating on an NT-style kernel and basic device drivers. The ReactOS name was selected during an IRC discussion. Its developers wanted to create a clean-room, independent implementation rather than copy Microsoft’s proprietary implementation. The project’s long-term technical ambition was to reproduce enough of the Windows system interfaces to run Windows applications and drivers while remaining free software. Development has consequently involved kernel work, user-mode libraries, graphical components, networking, storage, hardware support, and compatibility layers. In 2002, the ReactOS Foundation was established in Moscow, with Maxim Osowski and Aleksey Bragin as executive officers and several other contributors serving on its board. The foundation later became associated with attempts to obtain Russian governmental support for an open-source Windows-compatible platform. Demonstrations were given to Russian public figures, including Dmitry Medvedev and Vladimir Putin, and ReactOS was discussed in a 2015 Russian Ministry of Communications meeting about reducing dependence on imported proprietary software. These efforts did not produce government backing, and the Russia-based foundation was dissolved in 2015. A major organizational and legal episode occurred in January 2006, when developer Hartmut Birr alleged on the project’s developer mailing list that some code resembled code obtained by disassembling Microsoft Windows. The disputed material included a kernel-related function. The developer responsible for the implementation said it had been independently rewritten after studying behavior and that the similarity reflected the limited number of plausible implementations. Repository access was temporarily disabled while the issue was discussed. ReactOS subsequently strengthened its intellectual-property policy, required contributors to follow its reverse-engineering procedures, and conducted an internal audit. Access was restored, and the audit was substantially completed by 2007, although detailed results were not publicly released. The episode also complicated formal cooperation with the Wine project for a period. ReactOS has participated in Google Summer of Code and has held developer hackfests in Aachen, Cologne, and Berlin. Fundraising has included a continuing donation campaign begun in 2012, a proposed Thorium Core Cloud Desktop service, and the ReactOS Community Edition campaign in 2014. The cloud project failed to reach its target, while the Community Edition campaign raised partial funding and moved toward community voting on hardware and software priorities. Technically, ReactOS remains an evolving alpha operating system. It primarily targets x86 and AMD64 computers and incorporates code or technologies from projects such as Wine, Mesa 3D, lwIP, FreeBSD-related networking work, Haiku’s USB stack, and other open-source efforts. Some application compatibility exists, but the operating system lacks the maturity, hardware coverage, security assurance, and completeness expected of mainstream desktop platforms. The project therefore continues to serve chiefly as an open-source compatibility and operating-system research effort.

1. 2015Russia-based ReactOS Foundation is dissolved

   The Moscow-based foundation associated with Russian organizational activity is liquidated.

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2. 2012Development funding campaign begins

   ReactOS launches a campaign intended to finance additional development work.

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3. 2007Internal source audit nears completion

   ReactOS removes the audit notice from its homepage after its internal clean-room review is substantially completed.

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4. 2006Repository access temporarily restricted during code review

   The project pauses repository access while investigating allegations about the provenance of parts of the codebase.

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5. 2002ReactOS Foundation established

   A Moscow-based foundation is formed to support the project’s organizational and development activities.

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6. 1998ReactOS development starts

   The reorganized project adopts the ReactOS name and starts building an NT-compatible kernel and basic drivers.

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7. 1996FreeWin95 project begins

   Developers begin an effort to create a free implementation of Windows 95, the predecessor to ReactOS.

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ReactOS is positioned as a community-developed, open-source and Windows NT-compatible operating system for users, developers, researchers, and organizations interested in software freedom or legacy Windows application compatibility. Because it remains alpha-quality and feature-incomplete, the project emphasizes testing and evaluation rather than dependable production use.

• ReactOSOpen-source desktop operating system1998

  The central ReactOS software distribution provides an NT-like kernel, Win32-compatible system interfaces, a graphical desktop, system utilities, networking, storage, driver support, and bundled applications. It is designed for binary compatibility with Windows software and drivers, primarily on x86 and AMD64 PCs. The project remains alpha-quality and is recommended for testing and evaluation.

• ReactOS ExplorerDesktop shell and file manager

  ReactOS Explorer supplies the project’s graphical desktop and file-management experience. It is one of the components written partly in C++ and is intended to provide a familiar Windows-style environment within the broader ReactOS system.

• ReactXGraphics and multimedia compatibility

  ReactX is ReactOS’s in-house work on DirectX-compatible functionality. The wider graphics stack combines native 2D and OpenGL capabilities with compatibility techniques and Wine-related components for functionality that is not yet implemented directly.

• 2014ReactOS Community Edition

  International

  An Indiegogo campaign proposed a community-directed version based on ReactOS 0.4. Contributors and users would help determine which applications and hardware drivers should receive priority.

  Outcome. The flexible campaign ended on 1 June 2014 with $25,141 raised, after which the proposed voting process began.

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• 2013Thorium Core Cloud Desktop

  International

  ReactOS announced a proposed cloud-computing service that would use ReactOS as its core and deliver access to Windows-compatible applications from phones, tablets, workstations, and other connected devices.

  Outcome. The Kickstarter campaign sought $120,000 but raised $48,965 by 21 February 2014, below its target, and no funds were transferred.

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• 2012ReactOS development funding campaign

  International

  A campaign sought approximately €30,000 for additional ReactOS development. About half of the target had been collected by the end of the year, so the campaign continued without a fixed deadline. Funds were directed to ReactOS Deutschland e.V.; the organization considered indirect ways to support developers because of German tax and association-law constraints.

  Outcome. The full target and final outcome are not specified in the cited material.

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• 2006Strengthen clean-room reverse-engineering controlsStrategy

  Code-provenance allegations created legal and reputational concerns and disrupted cooperation with parts of the free-software community.

  What changed. ReactOS revised its intellectual-property policy, required contributor compliance, and performed an internal source audit.

  Aftermath. Repository access was restored and the audit process was later removed from the project homepage, although detailed results were not made public.

  • Wine — Wine barred several inactive ReactOS developers from contributing, and formal high-level cooperation became more difficult for a period.
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• 1998Shift from a Windows 95 clone to an NT-compatible operating systemStrategy

  The earlier FreeWin95 effort stalled without a public build and had unresolved design disagreements.

  What changed. Project members reorganized around a new operating-system architecture intended to reproduce Windows NT behavior and interfaces.

  Aftermath. The reorganized effort became ReactOS and has continued as a free-software compatibility project.

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• 2006Allegations concerning Windows-derived codeControversy

  A developer alleged that some ReactOS code had been copied or derived from disassembled Microsoft Windows binaries. The project temporarily restricted repository access, clarified its clean-room reverse-engineering rules, and conducted an internal audit. ReactOS said the disputed code had been independently reimplemented and did not publish detailed audit findings.

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• 2014ReactOS Community Edition crowdfunding campaign concluded

  An Indiegogo campaign sought funding for a community-directed edition based on ReactOS 0.4, with users voting on supported applications and hardware. The flexible campaign raised $25,141.

  CampaignProduct launch
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• 2013ReactOS announced the Thorium Core Cloud Desktop crowdfunding project

  The project proposed a cloud-computing service using ReactOS as its core to provide access to Windows-compatible applications from connected devices. The campaign raised less than its target and did not receive transferred funds.

  CampaignOther
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1. ReactOS
2. ReactOS official website