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. 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.
Wine is predominantly written using black-box testing reverse-engineering, to avoid copyright issues. Wine provides its compatibility layer for Windows runtime system (also called runtime environment) which translates Windows system calls into POSIX-compliant system calls, recreating the directory structure of Windows, and providing alternative implementations of Windows system libraries, system services through wineserver and various other components (such as Internet Explorer, the Windows Registry Editor, and msiexec ). Wine also provides a software library, named Winelib, against which developers can compile Windows applications to help port them to Unix-like systems. Wine ( recursive backronym for Wine Is Not an Emulator) 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. ReactOS (for Windows app and driver compatibly).