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ReactOS ○›｜Definition｜1st｜20261013192254-00-⌔
ReactOS
ReactOS is a free and open-source operating system for i586/amd64 personal computers that is intended to be binary-compatible with computer programs and device drivers developed for Windows Server 2003 and later versions of Microsoft Windows.12 ReactOS has been noted as a potential open-source drop-in replacement for Windows345 and has been of interest for its information on undocumented Windows APIs.6
ReactOS has been in development since 1996. As of August 2026, it is still considered to be feature-incomplete alpha software. Therefore, it is recommended by the developers to be used only for evaluation and testing purposes.78 However, many Windows applications are working, such as Adobe Reader 9.3, GIMP 2.6, and LibreOffice 5.4.910
ReactOS is primarily written in C, with some elements written in C++, such as the ReactOS File Explorer. The project partially implements Windows API functionality and has been ported to the AMD64 processor architecture.11 ReactOS is part of the FOSS ecosystem so it re-uses and collaborates with many other FOSS projects,1213 most notably the Wine project that presents a Windows compatibility layer for Unix-like operating systems.
Printed 2026-10-13.
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Link to original Footnotes
Holwerda, Thom (5 March 2009). “ReactOS Targets Windows 2003, Vista”. OSNews. Retrieved 14 October 2020. ↩
vicmarcal (14 April 2018). “ReactOS 0.4.8 released!!”. ReactOS.org Project News (Corporate blog). Retrieved 14 October 2020. With software specifically leaving NT5 behind, ReactOS is expanding its target to support NT6+ (Vista, Windows 8, Windows 10) software. ↩
Stahl, Louis-F. (23 June 2015). “Russland erklärt ReactOS zu favorisierter Windows-Alternative”. heise online. Retrieved 14 October 2020. ↩
Sixtus, Von Mario (20 February 2004). “ReactOS: Das Nicht-Windows” (in German). Spiegel Online. Retrieved 11 December 2009. ↩
Dvorak, John C. (4 April 2008). “What A New OS Needs”. PC Magazine. Retrieved 11 December 2009. ↩
Sugar, David (31 January 2006). “A reaction to ReactOS”. Free Software Magazine. Archived from the original on 10 August 2007. Retrieved 11 December 2009. ↩
Kupfer, Matthias; Bragin, Aleksey (14 March 2010). ReactOS — Das zu Windows binärkompatible Open-Source-Betriebssystem. Chemnitzer Linux-Tage (in German). Chemnitz, Germany. Retrieved 15 March 2010. ↩
Royal, Simon (16 February 2014). “ReactOS: A Windows Compatible Alternative OS”. lowendmac.com. Retrieved 10 January 2016. While the main core of ReactOS is built from scratch, it has some dependencies on existing software and protocols. It uses parts of Wine, networking in the form of lwIP, USB from Haiku, as well as FreeType, Mesa3D, and UniATA. ↩
Thom Holwerda (14 November 2007). “ReactOS Gets OpenOffice.org 2 Support; New Release Plans”. OSNews. ↩
Tests for 0.4.14 on reactos.org (February 2022) ↩
Holwerda, Thom (17 January 2009). “ReactOS: Looking Back Upon 2008”. OSNews. Retrieved 18 April 2019. ↩
“ReactOS gets USB Stack, with Help from Us”. Haiku. 20 February 2012. Retrieved 2 January 2016. The ReactOS and Haiku projects have had a friendly working relationship for several years now, with each group helping the other whenever possible. ↩
Vincent, Brian (15 May 2004). “Interview with Steven Edwards”. winehq.com. Retrieved 6 January 2016. BV: Wine and ReactOS have had a mutually beneficial relationship. Is there anything Wine could do different that would help ReactOS development?[…] BV: You guys have certainly contributed a lot of your work back to Wine, including some of the utilities you’ve written. For instance, the task manager was recently ported from ReactOS. Do you guys have any plans in the works for developing more tools? Steven: I really want to see a solitaire clone make it in to Wine and ReactOS.[…] At some point we are going to have to develop replacement components for everything in Windows so if there is a program that Wine needs and ReactOS implements it then I will try to make sure it’s released under a compatible license. ↩
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