
ReactOS is a
free and open-source
Free and open-source software (FOSS) is software available under a Software license, license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term ...
operating system
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs.
Time-sharing operating systems scheduler (computing), schedule tasks for ...
for
i586
The Pentium (also referred to as the i586 or P5 Pentium) is a microprocessor introduced by Intel on March 22, 1993. It is the first CPU using the Pentium brand.
Considered the fifth generation in the x86 (8086) compatible line of processors, s ...
/
amd64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new operating modes: 64-bit mode an ...
personal computer
A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...
s that is intended to be
binary-compatible with
computer program
A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes software documentation, documentation and other intangibl ...
s and
device driver
In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabli ...
s developed for
Windows Server 2003
Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT ...
and later versions of Microsoft Windows. ReactOS has been noted as a potential open-source
drop-in replacement for Windows
and has been of interest for its information on
undocumented Windows API
The Windows API, informally WinAPI, is the foundational application programming interface (API) that allows a computer program to access the features of the Microsoft Windows operating system in which the program is running. Programs can acces ...
s.
ReactOS has been in development since 1996. , 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.
However, many Windows applications are working, such as
Adobe Reader
Adobe Acrobat is a family of application software and web services developed by Adobe Inc. to view, create, manipulate, print and manage Portable Document Format (PDF) files.
The family comprises Acrobat Reader (formerly Reader), Acrobat (former ...
9.3,
GIMP
Gimp or GIMP may refer to:
Clothing
* Bondage suit, also called a gimp suit, a type of suit used in BDSM
* Bondage mask, also called a gimp mask, often worn in conjunction with a gimp suit
Embroidery and crafts
* Gimp (thread), an ornamental tr ...
2.6, and
LibreOffice
LibreOffice () is a free and open-source office productivity software suite developed by The Document Foundation (TDF). It was created in 2010 as a fork of OpenOffice.org, itself a successor to StarOffice. The suite includes applications ...
5.4.
[Tests for 0.4.14](_blank)
on reactos.org (February 2022)
ReactOS is primarily written in
C, with some elements written in
C++, such as the ReactOS
File Explorer
File Explorer, previously known as Windows Explorer, is a file manager application and default desktop environment that is included with releases of the Microsoft Windows operating system from Windows 95 onwards. It provides a graphical user i ...
. The project partially implements
Windows API
The Windows API, informally WinAPI, is the foundational application programming interface (API) that allows a computer program to access the features of the Microsoft Windows operating system in which the program is running. Programs can acces ...
functionality and has been ported to the
AMD64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new operating modes: 64-bit mode an ...
processor architecture.
ReactOS is part of the
FOSS
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...
ecosystem so it re-uses and collaborates with many other FOSS projects,
most notably the
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
project that presents a Windows compatibility layer for
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...
operating systems.
History
Early development
Around 1996, a group of
free and open-source software
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...
developers started a project called ''FreeWin95'' to implement a
clone of
Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft and the first of its Windows 9x family of operating systems, released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995. Windows 95 merged ...
. The project stalled in discussions on the design of the system.
While FreeWin95 had started out with high expectations, there still had not been any builds released to the public by the end of 1997. As a result, the project members, led by then coordinator Jason Filby, joined together to revive the project. The revived project sought to duplicate the functionality of
Windows NT
Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...
. In creating the new project, a new name, ''ReactOS'', was chosen. The project began development in February 1998 by creating the basis for a new NT kernel and basic drivers. The name ReactOS was coined during an IRC chat. While the term "OS" stood for operating system, the term "react" referred to the group's dissatisfaction inspired reaction to Microsoft's
monopolistic position.
In 2002, the ReactOS Foundation was established in Moscow with Maxim Osowski and Aleksey Bragin as executive officers; and Vladimir Bragin, Saveliy Tretiakov, and Alexey Ivanov on the board of directors.
In 2015, the foundation was liquidated.
Internal audit
In order to avoid copyright prosecution, ReactOS had to be expressly completely distinct and non-
derivative
In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...
from Windows, a goal that needed very careful work.
A claim was made on 17 January 2006 by developer Hartmut Birr on the ReactOS developers
mailing list
A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients.
Mailing lists are often rented or sold. If rented, the renter agrees to use the mailing list only at contra ...
(ros-dev) that ReactOS contained code derived from
disassembling Microsoft Windows.
The code that Birr disputed involved the function BadStack in syscall.S, as well as other unspecified items. Comparing this function to disassembled binaries from
Windows XP
Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...
, Birr argued that the BadStack function was simply
copy-pasted from Windows XP, given that they were identical. Alex Ionescu, the author of the code, asserted that while the Windows XP binary in question was indeed disassembled and studied, the code was not merely copy-pasted, but reimplemented; the reason why the functions were identical, Ionescu claimed, was because there was only one possible way to implement the function.
On 27 January 2006, the developers responsible for maintaining the ReactOS code repository disabled access after a meeting was held to discuss the allegations. When approached by
NewsForge, Microsoft declined to comment on the incident. Since ReactOS is a
free and open-source software
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...
development project, the claim triggered a negative reaction from the
free software community
The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run, study, modify, and share copies of software. Software which meets these requirements, ...
: in particular, Wine barred several inactive developers from providing contributions and formal high-level cooperation between the two projects remained difficult .
In a statement on its website, ReactOS cited differing legal definitions of what constitutes
clean-room reverse engineering as a cause for the conflict. To avoid potential litigation, companies sometimes enact a policy where reimplementation based on disassembled code must be written by someone other than the person having disassembled and examined the original code.
ReactOS clarified its Intellectual Property Policy Statement requirements on clean room reverse engineering to avoid potential infringement of United States law. An internal source code
audit
An audit is an "independent examination of financial information of any entity, whether profit oriented or not, irrespective of its size or legal form when such an examination is conducted with a view to express an opinion thereon." Auditing al ...
was conducted to ensure that only clean room reverse engineering was used, and all developers were made to sign an agreement committing them to comply with the project's policies on reverse engineering.
Contributors to its development were not affected by these events and all access to the software development tools was restored shortly afterward. In September 2007, with the audit nearing completion, the audit status was removed from the ReactOS homepage. Though the audit was completed, specific details were not made public, as it was only an internal effort to ensure compliance with the project's own policies.
Also, the 2004
leaked Windows source code was not seen as legal risk for ReactOS, as the
trade secret
A trade secret is a form of intellectual property (IP) comprising confidential information that is not generally known or readily ascertainable, derives economic value from its secrecy, and is protected by reasonable efforts to maintain its conf ...
was considered indefensible in court due to broad spread.
[Reset, Reboot, Restart, legal issues and the long road to 0.3]
"''Now as for the issue of leaked source code, I want to try to put all fears to rest. We don't know what the legal ramifications are for someone downloading and having leaked code, as the party that maintains copyright ownership of that code might still try to claim Trade Secrecy on information contained in the sources in a court of law. It is our point of view that the source code leaks of Windows have been spread to a broad enough audience that it would be impossible to claim the product is still under Trade Secrecy.''" on reactos.org by Steven Edwards (27 January 2006)
Axel Rietschin, who is a kernel engineer at Microsoft, claimed that he recognized some specific bits in the ReactOS kernel that are unlikely to result from a clean room reimplementation. He suggests that the project took source code from the Windows Research Kernel, which was licensed to universities and has been leaked multiple times. Internal data structures and variable names have the exact same name in both ReactOS and the research kernel.
Google Summer of Code participation
Starting in 2006, the ReactOS project participated in several
Google Summers of Code. For example, in the GSoC 2011,
ReactOS mentored a student project which integrated
lwIP into the network stack.
Lobbying for support in Russia
Between 2007 and 2015, Russian ReactOS contributors representing the ReactOS Foundation made efforts at lobbying the Russian federal government. , these efforts have not yielded government support for ReactOS, and the Russia-based ReactOS Foundation has been dissolved since November 2015.

* In 2007, then
State Duma
The State Duma is the lower house of the Federal Assembly (Russia), Federal Assembly of Russia, with the upper house being the Federation Council (Russia), Federation Council. It was established by the Constitution of Russia, Constitution of t ...
member and chairman of Russian Center of Free Technologies,
Viktor Alksnis met with project coordinator Aleksey Bragin, who gave a presentation and demonstration of the project, showing ReactOS running with
Total Commander
__NOTOC__
Total Commander is an orthodox file manager, i.e. it features two file list panels (selectable via tab key) and a Command-line interface, command line. It supports Tab (interface), multiple tabs for each panel.
Total Commander is deve ...
and
Mozilla Firefox
Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements curren ...
.
* In 2011, a demonstration was given to then president
Dmitry Medvedev
Dmitry Anatolyevich Medvedev (born 14 September 1965) is a Russian politician and lawyer who has served as Deputy Chairman of the Security Council of Russia since 2020. Medvedev was also President of Russia between 2008 and 2012 and Prime Mini ...
during a visit to a high school in Verhnerusskoe,
Stavropol
Stavropol (, ), known as Voroshilovsk from 1935 until 1943, is a city and the administrative centre of Stavropol Krai, in southern Russia. As of the 2021 Census, its population was 547,820, making it one of Russia's fastest growing cities.
E ...
, attended by one of the development team members.
* On 31 July 2012,
Vladimir Putin
Vladimir Vladimirovich Putin (born 7 October 1952) is a Russian politician and former intelligence officer who has served as President of Russia since 2012, having previously served from 2000 to 2008. Putin also served as Prime Minister of Ru ...
was also given a demonstration during his visit as
President of Russia
The president of Russia, officially the president of the Russian Federation (), is the executive head of state of Russia. The president is the chair of the State Council (Russia), Federal State Council and the President of Russia#Commander-in-ch ...
to
Seliger Youth Forum, attended by Marat Karatov, one of the development team members.
* On 1 April 2015, Bragin attended an expert meeting of the
Russian Ministry of Communications on reducing Russia's dependency from proprietary software imports. Its minutes name the "creation of an open source operating system based on ReactOS for PCs, laptops and other mobile devices", as well as the "creation of an open source operating system for servers based on ReactOS",
[Russland-erklaert-ReactOS-zu-favorisierter-Windows-Alternative](_blank)
on heise online by Louis-F. Stahl (23 June 2015, in German) placing it second among three named proposals.
Funding campaigns
On 1 May 2012, a €30,000 funding campaign was started to finance additional development projects. At the end of the year, approximately 50% of the funding goal was achieved and it was decided to continue the funding campaign without deadlines. The money went to ''ReactOS Deutschland
e. V.''. As the
tax law
Tax law or revenue law is an area of legal study in which public or sanctioned authorities, such as federal, state and municipal governments (as in the case of the US) use a body of rules and procedures (laws) to assess and collect taxes in a ...
in Germany for this form of a
registered voluntary association
A voluntary group or union (also sometimes called a voluntary organization, common-interest association, association, or society) is a group of individuals who enter into an agreement, usually as volunteers, to form a body (or organization) to a ...
(''
Eingetragener Verein
An (; "registered association" or "incorporated association"), abbreviated (), is a legal status for a civil registration, registered voluntary association in Germany. While any group may be called a , registration as confers many legal bene ...
'') makes it problematic to pay developers directly; indirect possibilities like
stipend
A stipend is a regular fixed sum of money paid for services or to defray expenses, such as for scholarship, internship, or apprenticeship. It is often distinct from an income or a salary because it does not necessarily represent payment for work pe ...
s were evaluated.
Thorium Core Cloud Desktop project
When ReactOS was awarded as Project of the Month on
SourceForge
SourceForge is a web service founded by Geoffrey B. Jeffery, Tim Perdue, and Drew Streib in November 1999. SourceForge provides a centralized software discovery platform, including an online platform for managing and hosting open-source soft ...
in June 2013, a
crowdfunding
Crowdfunding is the practice of funding a project or venture by raising money from a large number of people, typically via the internet. Crowdfunding is a form of crowdsourcing and Alternative Finance, alternative finance, to fund projects "withou ...
campaign on
Kickstarter
Kickstarter, PBC is an American Benefit corporation, public benefit corporation based in Brooklyn, New York City, that maintains a global crowdfunding platform focused on creativity. The company's stated mission is to "help bring creative project ...
was announced in an interview with the project's coordinator, Aleksey Bragin.
On 23 December 2013 the announced project was revealed as a Kickstarter campaign with the goal of US$120,000 was started. The ''Thorium Core Cloud Desktop'' dubbed
cloud computing
Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for ...
service would use ReactOS as core and could allow the use of Windows compatible applications from
mobile device
A mobile device or handheld device is a computer small enough to hold and operate in hand. Mobile devices are typically battery-powered and possess a flat-panel display and one or more built-in input devices, such as a touchscreen or keypad. ...
s (like
smartphone
A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...
s,
tablets),
workstation
A workstation is a special computer designed for technical or computational science, scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating syste ...
s, or any other connected device. On 21 February 2014, fundraising ended short of the target amount, with $48,965 of $120,000 raised, resulting in no transferred money.
ReactOS Community Edition
In April 2014, the ReactOS project announced an
Indiegogo
Indiegogo is an American crowdfunding website founded in 2008 by Danae Ringelmann, Slava Rubin, and Eric Schell. Its headquarters are in San Francisco, California. The site is one of the first sites to offer crowd funding. Indiegogo allows peo ...
campaign to launch ReactOS Community Edition, a version of ReactOS based on the 0.4 release. The flexible funding campaign had a goal of $50,000 with additional stretch goals beyond that. Development of ReactOS Community Edition would be community-centric, with ReactOS users voting and funding to decide which software and hardware drivers the project will aim to support. On 1 June 2014, the flexible crowdfunding campaign on Indiegogo ended, raising $25,141 for the development of the community edition, and the voting process to support hardware and software was started shortly thereafter.
ReactOS Hackfest
The ReactOS project organized a
hackfest from 7 to 12 August 2015, in the German city of
Aachen
Aachen is the List of cities in North Rhine-Westphalia by population, 13th-largest city in North Rhine-Westphalia and the List of cities in Germany by population, 27th-largest city of Germany, with around 261,000 inhabitants.
Aachen is locat ...
. The Hackfest resulted in many features being added to ReactOS.
The second hackfest was organized by the ReactOS project from 14 to 18 August 2017, in the German city of
Cologne
Cologne ( ; ; ) is the largest city of the States of Germany, German state of North Rhine-Westphalia and the List of cities in Germany by population, fourth-most populous city of Germany with nearly 1.1 million inhabitants in the city pr ...
.
The third and fourth hackfests were organized by the ReactOS project from 16 to 21 August 2018 and from 15 to 20 August 2019 in
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...
respectively.
Release history
Features
Programs
* ReactOS Explorer (''
File Explorer
File Explorer, previously known as Windows Explorer, is a file manager application and default desktop environment that is included with releases of the Microsoft Windows operating system from Windows 95 onwards. It provides a graphical user i ...
'')
* ReactOS Applications Manager
* Accessories
**
Calculator
An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.
The first solid-state electronic calculator was created in the early 1960s. Pocket-si ...
**
Command Prompt
A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...
**
Notepad
A notebook (also known as a notepad, writing pad, drawing pad, or legal pad) is a book or stack of paper pages that are often Ruled paper, ruled and used for purposes such as note-taking, Diary, journaling or other writing, drawing, or scrapbooki ...
**
Paint
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
**
WordPad
WordPad is a word processor software designed by Microsoft that was included in versions of Windows from Windows 95 through Windows 11, version 23H2. Similarly to its predecessor Microsoft Write, it served as a basic word processor, positione ...
**
Magnifier
**
On-Screen Keyboard
**
Remote Desktop Connection
Remote Desktop Protocol clients allow users to connect to servers running Remote Desktop Services, Azure Virtual Desktop, or non-Microsoft server software to enable Remote desktop software, remote desktop functionality. Since the release of Remote ...
** Multimedia Player (''
Media Player'')
**
Sound Recorder
** Volume Control
**
Character Map
**
Clipboard Viewer
** FontSub
** Keyboard Layout Switcher
** ReactX Diagnostic (''
DxDiag'')
**
Registry Editor
** SnapShot
**
Task Manager
In operating systems, a task manager is a system monitor program used to provide information about the processes and applications running on a computer, as well as the general status of the computer. Some implementations can also be used t ...
* Administrative Tools
**
Device Manager
**
Event Viewer
** Service Manager (''
Windows service
In Windows NT operating systems, a Windows service is a computer program that operates in the background. It is similar in concept to a Unix daemon. A Windows service must conform to the interface rules and protocols of the Service Control Manag ...
'')
** System Configuration (''
MSConfig'')
* Games
**
Solitaire
Solitaire may refer to:
Film and television
*'' Le Solitaire'', a 1987 French film
* ''Solitaire'' (1991 film), a Canadian drama film
* ''Solitaire'' (2008 film), a drama film
*''Solitaire'', 2016 Lebanese comedy film with Bassam Kousa
*"Solit ...
(''
Microsoft Solitaire'')
**
Spider Solitaire (''
Microsoft Spider Solitaire'')
**
WineMine (''
Microsoft Minesweeper'')
Commands

The following is a non-exhaustive list of
commands that are supported by the ReactOS
Command Prompt
A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...
.
* ?
*
alias
*
assoc
*
at
*
attrib
*
beep
*
cacls
*
call
Call or Calls may refer to:
Arts, entertainment, and media Games
* Call (poker), a bet matching an opponent's
* Call, in the game of contract bridge, a bid, pass, double, or redouble in the bidding stage
Music and dance
* Call (band), from L ...
*
cat
The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...
*
cd
*
chdir
*
chcp
*
choice
A choice is the range of different things from which a being can choose. The arrival at a choice may incorporate Motivation, motivators and Choice modelling, models.
Freedom of choice is generally cherished, whereas a severely limited or arti ...
*
clip
*
cls
*
color
Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though co ...
*
comp
Comp, COMP or Comps may refer to:
Places
In England:
* Comp, Kent
In France:
* Comps, Drôme
* Comps, Gard
* Comps, Gironde
* Comps-la-Grand-Ville
* Comps-sur-Artuby
Music
*Accompaniment, especially in jazz
** Comping (jazz)
*Compilatio ...
*
copy
*
ctty
*
date
*
dbgprint
*
del
Del, or nabla, is an operator used in mathematics (particularly in vector calculus) as a vector differential operator, usually represented by the nabla symbol ∇. When applied to a function defined on a one-dimensional domain, it denotes ...
*
delete
*
delay
*
dir
*
dirs
*
doskey
DOSKEY is a command in DOS, OS/2, Windows, and ReactOS that adds command history, macro functionality, and improved editing features to the COMMAND.COM and cmd.exe command-line interpreter shells.
History
The command was included as a termi ...
*
echo
In audio signal processing and acoustics, an echo is a reflection of sound that arrives at the listener with a delay after the direct sound. The delay is directly proportional to the distance of the reflecting surface from the source and the lis ...
*
echos
*
echoerr
*
echoserr
*
endlocal
*
eventcreate
*
erase
*
exit
Exit(s) may refer to:
Architecture and engineering
* Door
* Portal (architecture), an opening in the walls of a structure
* Emergency exit
* Overwing exit, a type of emergency exit on an airplane
* Exit ramp, a feature of a road interchange
A ...
*
find
*
for
For or FOR may refer to:
English language
*For, a preposition
*For, a complementizer
*For, a grammatical conjunction
Science and technology
* Fornax, a constellation
* for loop, a programming language statement
* Frame of reference, in physics
* ...
*
free
*
fsutil
*
goto
*
help
Help may refer to:
Arts, entertainment, and media
Films
* Help (2010 film), ''Help'' (2010 film), a Bollywood horror film
* Help (2021 theatrical film), ''Help'' (2021 theatrical film), a British psychological thriller film
* Help (2021 TV ...
*
history
History is the systematic study of the past, focusing primarily on the Human history, human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some t ...
*
hostname
In computer networking, a hostname (archaically nodename) is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication, such as the World Wide Web. Hos ...
*
if
*
label
A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product. Labels are most often affixed to packaging and containers using an adhesive, or sewing when affix ...
*
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...
*
md
*
mkdir
(make directory) command (computing), command in the Unix, DOS, Digital Research, DR FlexOS, IBM OS/2, Microsoft Windows, and ReactOS operating systems is used to make a new directory (file systems), directory. It is also available in the Unified ...
*
mklink
*
mode
*
more
*
move
Move or The Move may refer to:
Brands and enterprises
* Move (company), an American online real estate company
* Move (electronics store), a defunct Australian electronics retailer
* Daihatsu Move, a Japanese car
* PlayStation Move, a motion ...
*
path
A path is a route for physical travel – see Trail.
Path or PATH may also refer to:
Physical paths of different types
* Bicycle path
* Bridle path, used by people on horseback
* Course (navigation), the intended path of a vehicle
* Desir ...
*
pause
*
popd
*
prompt
*
pushd
*
rd
*
rmdir
In computing, rmdir (or rd) is a command which will remove an empty directory on various operating systems.
Implementations
The command is available in Unix (e.g. macOS, Solaris, AIX, HP-UX), Unix-like (e.g. FreeBSD, Linux), DOS, Digital ...
*
reg
*
rem
*
ren
*
rename
*
replace
*
sc
*
schtasks
*
screen
*
set
Set, The Set, SET or SETS may refer to:
Science, technology, and mathematics Mathematics
*Set (mathematics), a collection of elements
*Category of sets, the category whose objects and morphisms are sets and total functions, respectively
Electro ...
*
setlocal
*
shift
*
shutdown
*
sort
*
start
Start can refer to multiple topics:
* Takeoff, the phase of flight where an aircraft transitions from moving along the ground to flying through the air
* Starting lineup in sports
* Track and field#Starts use in race, Starts use in sport race
* S ...
*
taskkill
*
tee
*
time
Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...
*
timeout
* timer
*
title
A title is one or more words used before or after a person's name, in certain contexts. It may signify their generation, official position, military rank, professional or academic qualification, or nobility. In some languages, titles may be ins ...
*
touch
The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of bo ...
*
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...
*
type
Type may refer to:
Science and technology Computing
* Typing, producing text via a keyboard, typewriter, etc.
* Data type, collection of values used for computations.
* File type
* TYPE (DOS command), a command to display contents of a file.
* ...
*
uptime
Uptime is a Measurement, measure of system reliability, expressed as the period of system time, time a machine, typically a computer, has been continuously working and available. Uptime is the opposite of downtime.
It is often used as a measure ...
*
ver
*
verify
CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS (typically residi ...
*
vol
*
whoami
*
xcopy
On-going national language development
Presently, ReactOS has active development in:
Czech
Czech may refer to:
* Anything from or related to the Czech Republic, a country in Europe
** Czech language
** Czechs, the people of the area
** Czech culture
** Czech cuisine
* One of three mythical brothers, Lech, Czech, and Rus
*Czech (surnam ...
,
English,
Dutch,
Finnish,
French,
German,
Hebrew
Hebrew (; ''ʿÎbrit'') is a Northwest Semitic languages, Northwest Semitic language within the Afroasiatic languages, Afroasiatic language family. A regional dialect of the Canaanite languages, it was natively spoken by the Israelites and ...
,
Hungarian,
Indonesian,
Italian
Italian(s) may refer to:
* Anything of, from, or related to the people of Italy over the centuries
** Italians, a Romance ethnic group related to or simply a citizen of the Italian Republic or Italian Kingdom
** Italian language, a Romance languag ...
,
Japanese,
Mandarin Chinese
Mandarin ( ; zh, s=, t=, p=Guānhuà, l=Mandarin (bureaucrat), officials' speech) is the largest branch of the Sinitic languages. Mandarin varieties are spoken by 70 percent of all Chinese speakers over a large geographical area that stretch ...
,
Norwegian,
Polish,
Russian,
Spanish,
Swedish,
Thai,
Ukrainian.
Development
ReactOS core development
ReactOS is primarily written in
C, with some elements, such as ReactOS Explorer and the sound stack, written in
C++. The project compiles using both
MinGW
MinGW ("Minimalist GNU for Windows"), formerly mingw32, is a free and open source software development environment to create Microsoft Windows applications.
MinGW includes a port of the GNU Compiler Collection (GCC), GNU Binutils for Windows ...
and
Microsoft Visual Studio
Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platforms ...
, and contributes to the development of the build systems used through the submission of
patches to its components.
The developers aim to make the kernel and usermode application programming interface (API) more compatible with Windows NT version 5.2 (
Windows Server 2003
Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT ...
) and to add support for more applications and hardware, with plans to target newer versions of Windows as development matures.
DirectX
Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with "Direct" ...
support is undertaken through ReactX, an in-house implementation. 2D and
OpenGL
OpenGL (Open Graphics Library) is a Language-independent specification, cross-language, cross-platform application programming interface (API) for rendering 2D computer graphics, 2D and 3D computer graphics, 3D vector graphics. The API is typic ...
3D hardware-accelerated rendering is done natively, while other drawing functionality such as
Direct3D
Direct3D is a graphics application programming interface (API) for Microsoft Windows. Part of DirectX, Direct3D is used to render three-dimensional graphics in applications where performance is important, such as games. Direct3D uses hardware ...
is redirected to OpenGL as a stopgap solution, mostly using
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
's code such as
WineD3D.
The development progress is influenced by the size of the development team and the level of experience among them. As an estimate of the effort required to implement
Windows 7
Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...
, Microsoft employed 1,000 or so developers, organized into 25 teams, with each team averaging 40 developers. , in the ReactOS entry in Open Hub, Ohloh, the page followed through the "Very large, active development team" link lists 33 developers who have contributed over a 12-month period and a wikt:cumulative, cumulative total of 104 present and former users who have contributed code to the project via Apache Subversion since its inception. In his presentation at Hackmeeting 2009 in Milan, ReactOS developer Michele C. noted that most of the developers learn about Windows architecture while working on ReactOS and have no prior knowledge.
While ReactOS targets mainly the x86/
AMD64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new operating modes: 64-bit mode an ...
personal computer, PC platform, an effort to port to the ARM architecture was at one point "under way",
while it did not produce much functionality and was abandoned along with a port to PowerPC, that is no longer actively maintained.
Support for the Xbox (console), Xbox and the NEC PC-9800, a variant IA-32 architecture, was added through the use of an architecture-specific hardware abstraction, HAL.
Improved 64-bit support for ReactOS is "being worked on", however, development seems to be going slowly.
Collaboration and reuse
While ReactOS has the aim to build a Windows-compatible kernel as open-source software, much of the surrounding required functionality to create a complete OS is already available in the greater open-source ecosystem.
When available and possible, ReactOS therefore builds on and collaborates with already existing open-source projects.
Conversely, projects like
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
,
and formerly Captive NTFS and Longene re-use the open-source ReactOS code-base as well.
Hardware driver stack
On the device driver, hardware driver side, for instance the UniATA project provides Serial ATA drivers for ReactOS.
The project has also experimented with using the FullFAT library in its rewrite of its File Allocation Table, FAT Installable File System. ReactOS makes use of the USB stack from Haiku (operating system), Haiku both as a reference and as a foundation for its USB support. Mesa (computer graphics), Mesa 3D provides
OpenGL
OpenGL (Open Graphics Library) is a Language-independent specification, cross-language, cross-platform application programming interface (API) for rendering 2D computer graphics, 2D and 3D computer graphics, 3D vector graphics. The API is typic ...
rendering.
Networking
ReactOS's network stack is built on the Transmission Control Protocol, TCP portion of OSKit's port of the network stack in FreeBSD, along with an internally developed implementation for packet-oriented protocols like Internet Protocol, IP. Later,
lwIP was integrated into the ReactOS network stack.
Wine cooperation

The ReactOS and the
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
projects share the goal to run binary Windows software natively and can therefore share many dependencies and development.
ReactOS uses portions of the
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
project so that it can benefit from Wine's progress in implementing the Windows API#Versions, Win32 Application programming interface, API.
While Wine's Native API, NTDLL, Windows USER, USER32, Microsoft Windows library files#KERNEL32.DLL, KERNEL32, Microsoft Windows library files#GDI32.DLL, GDI32, and Microsoft Windows library files#ADVAPI32.DLL, ADVAPI32 components cannot be used directly by ReactOS due to architectural differences, Snippet (programming), code snippets of them and other parts can be shared between both projects. The kernel is developed by ReactOS separately as Wine relies here on existing
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...
kernels.
Separately, the experimental ''Arwinss'' branch was created as an alternative means to improve USER32 and GDI32 support through an alternative implementation of the Win32 API. Whereas ReactOS's original Win32 subsystem was closely modeled after its equivalent in Windows, Arwinss combines the architecture of that subsystem with the corresponding implementation in Wine. To this end, Arwinss uses Wine's GDI32 and USER32 libraries with few changes to take fuller advantage of Wine's existing software compatibility. Arwinss also allows the user to optionally use a remote X Window System, X server instead of a local display.
Other
The Tango Desktop Project initiative provides open-source design guidelines and resources (as icon (computing), icons) for applications on desktop environments. FreeType is an open-source software development library (computing), library, used to render text on to bitmaps and provides support for other font-related operations.
The ''KernelEx'' project is a Windows-API extension and compatibility layer project, which provides open-source implementations of some Windows-APIs. Other contributing projects are
MinGW
MinGW ("Minimalist GNU for Windows"), formerly mingw32, is a free and open source software development environment to create Microsoft Windows applications.
MinGW includes a port of the GNU Compiler Collection (GCC), GNU Binutils for Windows ...
, SYSLINUX, adns, International Components for Unicode, ICU, GraphApp, Ext2, GNU FreeFont, DejaVu fonts, and Liberation fonts.
Forks
Forks based on ReactOS exist:
*Ekush OS (2004)
[Ekush Emulator and Its License Pains](_blank)
on OSNews by Eugenia Loli (10 November 2004)[Ekush OS – stolen source code/copyright violation](_blank)
(archived 2004)[Ekush The Next Generation Operating System]
on akshor.com (archived 2004)
Reception
Various people have acknowledged ReactOS and the implications of having a viable open-source
drop-in replacement for Windows.
A 2004 article and interview of the German weekly magazine ''Der Spiegel'' describes ReactOS as directed at Windows users who want to renounce use of proprietary software, proprietary commercial software without having to switch to Linux.
DistroWatch, a Linux distribution's monitoring Web site, also lists ReactOS and describes it as "a free and open-source operating system based on the best design principles found in the Architecture of Windows NT, Windows NT architecture."
In his column for Free Software Magazine, David Sugar noted in 2006 that ReactOS would allow the use of applications depending on older versions of Windows whose APIs have been deprecated. He also recognized its potential to expand the total deployed base of free software, and as a resource for developers wanting to know
undocumented Windows APIs in the course of writing portable applications.
PC Magazine columnist John C. Dvorak remarked in 2008 that the Windows NT architecture had remained largely unchanged, making it an ideal candidate for cloning, and believed that ReactOS could be "a bigger threat than Linux to Microsoft's dominance".
In response to Dvorak's column, ZDNet technology journalist Dana Blankenhorn noted in 2008 that a lack of corporate sponsors and partners had rendered the project harmless to Microsoft. Echoing this, Thom Holwerda of OSNews in 2009 categorized ReactOS under a family of hobby operating systems maintained only by small groups of developers working in their spare time, lacking the financial support of more mainstream operating systems and the legacy of formerly mainstream ones such as RISC OS.
In October 2015, a International Data Group#IDG Global Brands, Network World review of ReactOS v0.3.17 noted "It's just like running Windows 2000" and praised the application package manager, a feature the original Windows is missing.
In August 2018, Jesse Smith from DistroWatch Weekly reviewed ReactOS v0.4.9, reporting that it suffered from limited hardware support and that it tended to lock up under load. He concluded: "[it] should be used with caution and probably not as a main, day-to-day operating system"
Awards
The ReactOS Project won on the annual
Seliger Youth Forum "The Best Presentation" award with 100,000 Russian rubles ($2700) in 2011, attended by Alexander Rechitskiy, one of the development team members.
ReactOS was a featured project on
SourceForge
SourceForge is a web service founded by Geoffrey B. Jeffery, Tim Perdue, and Drew Streib in November 1999. SourceForge provides a centralized software discovery platform, including an online platform for managing and hosting open-source soft ...
for the weeks beginning on 27 February 2012, 25 April 2013,
and several others. It was Project of the Month on SourceForge for June 2013
and February 2019.
See also
*Binary-code compatibility
*Cooperative Linux, coLinux, a project allowing Microsoft Windows and the Linux kernel to run simultaneously in parallel on the same machine
*FreeDOS, a clone of MS-DOS
*eComStation and ArcaOS, two independent proprietary continuations of OS/2 (source code licensed from IBM), which IBM co-created with Microsoft and shares some design elements with MS-DOS and Windows
** osFree,
an early attempt to clone OS/2
*Haiku (operating system), Haiku, a clone of BeOS
*Longene, a hybrid operating system kernel intended to be binary-compatible with both the Microsoft Windows and Linux ecosystems
*NDISwrapper, a re-creation of Windows NT kernel parts inside the Linux Kernel to allow the use of Windows drivers in Linux
*
Wine
Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
, a compatibility layer that runs Microsoft Windows applications on Unix-like operating systems
*List of alternative shells for Windows
*Timelines of: Timeline of Intel, Intel / Timeline of Microsoft, Microsoft / Timeline of Microsoft Windows, Microsoft Windows / Timeline of operating systems, other operating systems (List of operating systems, List)
*Comparison of operating systems
Notes
References
External links
*
{{Authority control
ReactOS,
1998 software
Alpha software
Articles containing video clips
Free software operating systems
Free software programmed in C
Free software programmed in C++
Live CD
Operating system distributions bootable from read-only media
Software derived from or incorporating Wine
Upcoming software
Window-based operating systems
X86-64 operating systems
IA-32 operating systems
Works involved in plagiarism controversies