XFree86 is an implementation of the X Window System. It was originally written for Unix-like operating systems on IBM PC compatibles and was available for many other operating systems and platforms. It is free and open source software under the XFree86 License version 1.1. It was developed by the XFree86 Project, Inc. The lead developer was David Dawes. The last released version was 4.8.0, released December 2008. The last XFree86 CVS commit was made on May 18, 2009; the project was confirmed dormant in December 2011. For most of the 1990s and early 2000s, the project was the source of most innovation in X and was the de facto steward of X development. Until early 2004, it was almost universal on Linux and the BSDs. In February 2004, with version 4.4.0, The XFree86 Project began distributing new code with a copyright license that the Free Software Foundation considered GPL incompatible. Most open source operating systems using XFree86 found this unacceptable and moved to a fork from before the license change. The first fork was the abortive Xouvert, but X.Org Server soon became dominant. Most XFree86 developers also moved to X.Org. Usage While XFree86 was widely used by most Unix-like computer operating systems before its license change with version 4.4.0, it has since then been superseded by X.org and is used rarely nowadays. The last remaining operating system distribution to use it was NetBSD, which shipped some platforms with 4.5.0 by default until removing it as obsolete in 2015. and later releases use X.org by default on various ports (including i386 and amd64), and X.org is available through NetBSD pkgsrc for architectures for which XFree86 remains the default because of better support. , the netbsd-7 branch and release were the last to potentially contain XFree86, and XFree86 was completely removed before netbsd-8 branch and release in 2018. Architecture The XFree86 server communicates with the host operating system's kernel to drive input and output devices, with the exception of graphics cards. These are generally managed directly by XFree86, so it includes its own drivers for all graphic cards a user might have. Some cards are supported by vendors themselves via binary-only drivers. Since version 4.0, XFree86 has supported certain accelerated 3D graphics cards via the GLX and DRI extensions. Also in the version 4.0, XFree86 moved to a new driver model, from one X server binary per driver to a unique X