Wine (software)
Wine (formerly a recursive backronym for "Wine Is Not an Emulator", now just "Wine") is a free and open-source compatibility layer that aims to allow application software and computer games developed for Microsoft Windows to run on Unix-like operating systems. Wine also provides a software library, named "Winelib", against which developers can compile Windows applications to help port them to Unix-like systems. Wine provides its compatibility layer for Windows runtime system (also called runtime environment) which translates Windows API calls into POSIX API calls, recreating the directory structure of Windows, and providing alternative implementations of  Windows system libraries, system services through codice_1 and various other components (such as Internet Explorer, the Windows Registry Editor, and msiexec). Wine is predominantly written using black-box testing reverse-engineering, to avoid copyright issues. The selection of "Wine is Not an Emulator" as the name of the Wine Project was the result of a naming discussion in August 1993 and credited to David Niemi. There is some confusion caused by an early FAQ using "Windows Emulator" and other invalid sources that appear after the Wine Project name being set. No code emulation or virtualization occurs when running a Windows  application under Wine. "Emulation" usually would refer to execution of compiled code intended for one processor (such as x86) by interpreting/recompiling software running on a different processor (such as PowerPC). While the name sometimes appears in the forms "WINE" and "wine", the project developers have agreed to standardize on the form "Wine". Wine is primarily developed for Linux and macOS, and there are, , well-maintained packages available for both platforms. In a 2007 survey by desktoplinux.com of 38,500 Linux desktop users, 31.5% of respondents reported using Wine to run Windows applications. This plurality was larger than all x86 virtualization  programs combined, as well as larger than the 27.9% who reported not running Windows applications. History. Bob Amstadt, the initial project leader, and Eric Youngdale started the Wine project in 1993 as a way to run Windows applications on Linux. It was inspired by two Sun Microsystems' products, the Wabi for the Solaris operating system, and the Public Windows Initiative, which was an attempt to get the Windows API fully reimplemented in the public domain as an ISO standard but rejected due to pressure from Microsoft in 1996. Wine originally targeted 16-bit applications for Windows 3.x, but focuses on  32-bit and 64-bit versions which have become the standard on newer operating systems. The project originated in discussions on Usenet in comp.os.linux in June 1993. Alexandre Julliard has led the project since 1994. The project has proven time-consuming and difficult for the developers, mostly because of incomplete and incorrect documentation of the Windows API. While Microsoft extensively documents most Win32 functions, some areas such as file formats and protocols have no publicly available specification from Microsoft, and Windows also includes undocumented low-level functions, undocumented behavior and obscure bugs that Wine must duplicate precisely in order to  allow some applications to work properly. Consequently, the Wine team has reverse-engineered many function calls and file formats in such areas as thunking. The Wine project originally released Wine under the same MIT License as the X Window System, but owing to concern about proprietary versions of Wine not contributing their changes back to the core project, work as of March 2002 has used the LGPL for its licensing. Wine officially entered beta with version 0.9 on 25 October 2005. Version 1.0 was released on 17 June 2008, after 15 years of development. Version 1.2 was released on 16  July 2010, version 1.4 on 7 March 2012, version 1.6 on 18 July 2013 and version 1.8 on 19 December 2015. Development versions are released roughly every two weeks. Wine-staging is an independently maintained set of aggressive patches not deemed ready by WineHQ developers for merging into the Wine repository, but still considered useful by the wine-compholio fork. It mainly covers experimental functions and bug fixes. Since January 2017, patches in wine-staging begins to be actively merged into the WineHQ upstream as wine-compholio transferred the project to Alistair Leslie-Hughes, a key WineHQ developer. Corporate sponsorship . The main corporate sponsor of Wine is CodeWeavers, which employs Julliard and many other Wine developers to work on Wine and on CrossOver, CodeWeavers' supported version of Wine. CrossOver includes some application-specific tweaks not considered suitable for the upstream version, as well as some additional proprietary components. The involvement of Corel for a time assisted the project, chiefly by employing Julliard and others to work on it. Corel had an interest in porting WordPerfect Office, its office suite, to Linux (especially Corel Linux). Corel later cancelled all Linux-related projects after Microsoft made major investments in Corel, stopping their  Wine effort. Other corporate sponsors include Google, which hired CodeWeavers to fix Wine so Picasa ran well enough to be ported directly to Linux using the same binary as on Windows; Google later paid for improvements to Wine's support for Adobe Photoshop CS2. Wine is also a regular beneficiary of Google's Summer of Code program. Design. The goal of Wine is to implement the Windows APIs fully or partially that are required by programs that the users of Wine wish to run on top of a Unix-like system. Basic architecture. The programming interface of Microsoft Windows consists  largely of dynamic-link libraries (DLLs). These contain a huge number of wrapper sub-routines for the system calls of the kernel, the NTOS kernel-mode program (ntoskrnl.exe). A typical Windows program calls some Windows DLLs, which in turn calls user-mode gdi/user32 libraries, which in turn uses the kernel32.dll (win32 subsystem) responsible for dealing with the kernel through system calls. The system-call layer is considered private to Microsoft programmers as documentation is not publicly available, and published interfaces all rely on subsystems running on top of the kernel. Besides these, there are a number of programming interfaces  implemented as services that run as separate processes. Applications communicate with user-mode services through RPCs. Wine implements the Windows application binary interface (ABI) entirely in user space, rather than as a kernel module. Wine mostly mirrors the hierarchy, with services normally provided by the kernel in Windows instead provided by a daemon known as the wineserver, whose task is to implement basic Windows functionality, as well as integration with the X Window System, and translation of signals into native Windows exceptions. Although Wineserver implements some aspects of the Windows kernel, it is not possible to use native Windows drivers  with it, due to Wine's underlying architecture. This prevents certain applications and games from working, for example those using StarForce copy-protection which requires virtual device drivers to be installed. Libraries and applications. Wine allows for loading both Windows DLLs and Unix shared objects for its Windows programs. Its built-in implementation of the most basic Windows DLLs, namely NTDLL, KERNEL32, GDI32, and USER32, uses the shared object method because they must use functions in the host operating system as well. Higher-level libraries, such as WineD3D, are free to use the DLL format. In many cases users can  choose to load a DLL from Windows instead of the one implemented by Wine. Doing so can provide functionalities not yet implemented by Wine, but may also cause malfunctions if it relies on something else not present in Wine. Wine tracks its state of implementation through automated unit testing done at every git commit. Graphics and gaming. While most office software does not make use of complex GPU-accelerated graphics APIs, computer games do. To run these games properly, Wine would have to forward the drawing instructions to the host OS, and even translate them to something the host can  understand. DirectX is a collection of Microsoft APIs for rendering, audio and input. As of 2019, Wine 4.0 contains a DirectX 12 implementation for Vulkan API, and DirectX 11.2 for OpenGL. Wine 4.0 also allows Wine to run Vulkan applications by handing draw commands to the host OS, or in the case of macOS, by translating them into the Metal API by MoltenVK. Direct3D. Much of Wine's DirectX effort goes into building WineD3D, a translation layer from Direct3D and DirectDraw API calls into OpenGL. As of 2019, this component supports up to DirectX 11. As of , Wine is good  enough to run "Overwatch" with D3D11. Besides being used in Wine, WineD3D DLLs have also been used on Windows itself, allowing for older GPUs to run games using newer DirectX versions and for old DDraw-based games to render correctly. Some work is ongoing to move the Direct3D backend to Vulkan API. Direct3D 12 support in 4.0 is provided by a "vkd3d" subproject, and WineD3D has in 2019 been experimentally ported to use the Vulkan API. Another implementation, DXVK, translates Direct3D 9, 10, and 11 calls using Vulkan as well and is a separate project. Wine, when patched, can alternatively  run Direct3D 9 API commands directly via a free and open-source Gallium3D State Tracker (aka Gallium3D GPU driver) without translation into OpenGL API calls. In this case, the Gallium3D layer allows a direct pass-through of DX9 drawing commands which results in performance improvements of up to a factor of 2. As of 2020, the project is named Gallium.Nine. It is available now as a separate standalone package and no longer needs a patched Wine version. User interface. Wine is usually invoked from the command-line interpreter: codice_2. winecfg. There is the utility codice_3 that starts a graphical  user interface with controls for adjusting basic options. It is a GUI configuration utility included with Wine. Winecfg makes configuring Wine easier by making it unnecessary to edit the registry directly, although, if needed, this can be done with the included registry editor (similar to Windows "regedit"). Third-party applications. Some applications require more tweaking than simply installing the application in order to work properly, such as manually configuring Wine to use certain Windows DLLs. The Wine project does not integrate such workarounds into the Wine codebase, instead preferring to focus solely on improving Wine's implementation of the Windows  API. While this approach focuses Wine development on long-term compatibility, it makes it difficult for users to run applications that require workarounds. Consequently, many third-party applications have been created to ease the use of those applications that do not work "out of the box" within Wine itself. The Wine wiki maintains a page of current and obsolete third-party applications. Functionality. The developers of the Direct3D portions of Wine have continued to implement new features such as pixel shaders to increase game support. Wine can also use native DLLs directly, thus increasing functionality, but then a license for  Windows is needed unless the DLLs were distributed with the application itself. Wine also includes its own open-source implementations of several Windows programs, such as "Notepad", "WordPad", "Control Panel", "Internet Explorer", and "Windows Explorer". The Wine Application Database (AppDB) is a community-maintained on-line database about which Windows programs works with Wine and how well they work. Backward compatibility. Wine ensures good backward compatibility with legacy Windows applications, including those written for Windows 3.1x. Wine can mimic different Windows versions required for some programs, going as far back as Windows version 2.0. However, Windows 1.x and Windows 2.x  support was removed from Wine development version 1.3.12. If DOSBox is installed on the system (see below on MS-DOS), Wine development version 1.3.12 and later nevertheless show the "Windows 2.0" option for the Windows version to mimic, but Wine still will not run most Windows 2.0 programs because MS-DOS and Windows functions are not currently integrated. Backward compatibility in Wine is generally superior to that of Windows, as newer versions of Windows can force users to upgrade legacy Windows applications, and may break abandoned software forever as there is nobody adjusting the program for the changes in the  operating system. In many cases, Wine can offer better legacy support than newer versions of Windows with "Compatibility Mode". Wine can run 16-bit Windows programs (Win16) on a 64-bit operating system, which uses an x86-64 (64-bit) CPU, a functionality not found in 64-bit versions of Microsoft Windows. WineVDM allows 16-bit Windows applications to run on 64-bit versions of Windows. Wine partially supports Windows console applications, and the user can choose which backend to use to manage the console (choices include raw streams, curses, and user32). When using the raw streams or curses backends , Windows applications will run in a Unix terminal. 64-bit applications. Preliminary support for 64-bit Windows applications was added to Wine 1.1.10, in December 2008. , the support is considered stable. The two versions of Wine are built separately, and as a result only building wine64 produces an environment only capable of running x86-64 applications. , Wine has stable support for a WoW64 build, which allows both 32-bit and 64-bit Windows applications to run inside the same Wine instance. To perform such a build, one must first build the 64-bit version, and then build the 32-bit  version referencing the 64-bit version. Just like Microsoft's WoW64, the 32-bit build process will add parts necessary for handling 32-bit programs to the 64-bit build. This functionality is seen from at least 2010. MS-DOS. Early versions of Microsoft Windows run on top of MS-DOS, and Windows programs may depend on MS-DOS programs to be usable. Wine does not have good support for MS-DOS, but starting with development version 1.3.12, Wine tries running MS-DOS programs in DOSBox if DOSBox is available on the system. However, due to a bug, current versions  of Wine incorrectly identify Windows 1.x and Windows 2.x programs as MS-DOS programs, attempting to run them in DOSBox (which does not work). Winelib. Wine provides Winelib, which allows its shared-object implementations of the Windows API to be used as actual libraries for a Unix program. This allows for Windows code to be built into native Unix executables. Since October 2010, Winelib also works on the ARM platform. Non-x86 architectures. Support for Solaris SPARC was dropped in version 1.5.26. ARM, Windows CE, and Windows RT. Wine provides some support for ARM (as well as ARM64/AArch64) processors  and the Windows flavors that run on it. , Wine can run ARM/Win32 applications intended for unlocked Windows RT devices (but not Windows RT programs). Windows CE support (either x86 or ARM) is missing, but an unofficial, pre-alpha proof-of-concept version called WineCE allows for some support. Wine for Android. On 3 February 2013 at the FOSDEM talk in Brussels, Alexandre Julliard demonstrated an early demo of Wine running on Google's Android operating system. Experimental builds of WINE for Android (x86 and ARM) were released in late 2017. It has been routinely updated by the official developers  ever since. The default builds do not implement cross-architecture emulation via QEMU, and as a result ARM versions will only run ARM applications that use the Win32 API. Microsoft applications. Wine, by default, uses specialized Windows builds of Gecko and Mono to substitute for Microsoft's Internet Explorer and .NET Framework. Wine has built-in implementations of JScript and VBScript. It is possible to download and run Microsoft's installers for those programs through winetricks or manually. Wine is not known to have good support for most versions of Internet Explorer (IE). Of all the reasonably recent versions, Internet  Explorer 8 for Windows XP is the only version that reports a usable rating on Wine's AppDB, out-of-the-box. However Google Chrome gets a gold rating (as of Wine 5.5-staging), and Microsoft's IE replacement web browser Edge, is known to be based on that browser (after switching from Microsoft's own rendering engine). Winetricks offer auto-installation for Internet Explorer 6 through 8, so these versions can be reasonably expected to work with its built-in workarounds. An alternative for installing Internet Explorer directly is to use the now-defunct IEs4Linux. It is not compatible  with the latest versions of Wine, and the development of IEs4Linux is inactive. Other versions of Wine. The core Wine development aims at a correct implementation of the Windows API as a whole and has sometimes lagged in some areas of compatibility with certain applications. Direct3D, for example, remained unimplemented until 1998, although newer releases have had an increasingly complete implementation. CrossOver. CodeWeavers markets CrossOver specifically for running Microsoft Office and other major Windows applications, including some games. CodeWeavers employs Alexandre Julliard to work on Wine and contributes most of its code to the Wine project under the LGPL. CodeWeavers  also released a new version called CrossOver Mac for Intel-based Apple Macintosh computers on 10 January 2007. As of 2012, CrossOver includes the functionality of both the CrossOver Games and CrossOver Pro lines therefore CrossOver Games and CrossOver Pro are no longer available as single products. CrossOver Games was optimized for running Windows video games. Unlike CrossOver, it didn't focus on providing the most stable version of Wine. Instead, experimental features are provided to support newer games. WINE@Etersoft. The Russian company Etersoft has been developing a proprietary version of Wine since 2006. WINE@Etersoft supports popular Russian applications (for  example, by 1C Company). Proton. On 21 August 2018, Valve announced a new variation of Wine, named Proton, designed to integrate with the Linux version of the company's Steam software (including Steam installations built into their Linux-based SteamOS operating system and Steam Machine computers). Valve's goal for Proton is to enable Steam users on Linux to play games which lack a native Linux port (particularly back-catalog games), and ultimately, through integration with Steam as well as improvements to game support relative to mainline Wine, to give users "the same simple plug-and-play experience" that they  would get if they were playing the game natively on Linux. Proton entered public beta immediately upon being announced. Valve had already been collaborating with CodeWeavers since 2016 to develop improvements to Wine's gaming performance, some of which have been merged to the upstream Wine project. Some of the specific improvements incorporated into Proton include Vulkan-based Direct3D 9, 10, 11, and 12 implementations via vkd3d, DXVK, and D9VK multi-threaded performance improvements via esync, improved handling of fullscreen games, and better automatic game controller hardware support. Proton is fully open-source and available via GitHub. Other projects using  Wine source code. Other projects using Wine source code include: Reception. The Wine project has received a number of technical and philosophical complaints and concerns over the years. Security. Because of Wine's ability to run Windows binary code, concerns have been raised over native Windows viruses and malware affecting Unix-like operating systems as Wine can run limited malware made for Windows. A 2018 security analysis found that 5 out of 30 malware samples were able to successfully run through Wine, a relatively low rate that nevertheless posed a security risk. For this reason the developers of Wine recommend  never running it as the superuser. Malware research software such as ZeroWine runs Wine on Linux in a virtual machine, to keep the malware completely isolated from the host system. An alternative to improve the security without the performance cost of using a virtual machine, is to run Wine in an LXC container, as Anbox software is doing by default with Android. Another security concern is when the implemented specifications are ill-designed and allow for security compromise. Because Wine implements these specifications, it will likely also implement any security vulnerabilities they contain. One instance of this problem was the  2006 Windows Metafile vulnerability, which saw Wine implementing the vulnerable SETABORTPROC escape. Wine vs. native Unix applications. A common concern about Wine is that its existence means that vendors are less likely to write native Linux, macOS, and BSD applications. As an example of this, it is worth considering IBM's 1994 operating system, OS/2 Warp. An article describes the weaknesses of OS/2 which killed it, the first one being: However, OS/2 had many problems with end user acceptance. Perhaps the most serious was that most computers sold already came with DOS and Windows, and many people didn't bother  to evaluate OS/2 on its merits due to already having an operating system. "Bundling" of DOS and Windows and the chilling effect this had on the operating system market frequently came up in United States v. Microsoft Corporation. The Wine project itself responds to the specific complaint of "encouraging" the continued development for the Windows API on one of its wiki pages: Also, the Wine Wiki page claims that Wine can help break the chicken-and-egg problem for Linux on the desktop: The use of Wine for gaming has proved specifically controversial in the Linux community, as some feel  it is preventing, or at least hindering, the further growth of native Linux gaming on the platform. Microsoft. Until 2020, Microsoft had not made any public statements about Wine. However, the Windows Update software will block updates to Microsoft applications running in Wine. On 16 February 2005, Ivan Leo Puoti discovered that Microsoft had started checking the Windows Registry for the Wine configuration key and would block the Windows Update for any component. As Puoti noted: "It's also the first time Microsoft acknowledges the existence of Wine." In January 2020, Microsoft cited Wine as a positive consequence of being  able to reimplement APIs, in its amicus curiae brief for Google LLC v. Oracle America, Inc.