the Linux kernel (like the Linux-libre kernel) and not the mainline Linux kernel. BSD kernels Debian GNU/kFreeBSD is an operating system for IA-32 and x86-64 computer architectures. It is a distribution of GNU with Debian package management and the kernel of FreeBSD. The k in kFreeBSD is an abbreviation for kernel of, and reflects the fact that only the kernel of the complete FreeBSD operating system is used. The operating system was officially released with Debian Squeeze (6.0) on February 6, 2011. One Debian GNU/kFreeBSD live CD is Ging, which is no longer maintained. was an experimental port of GNU user-land applications to NetBSD kernel. No official release of this operating system was made; although work was conducted on ports for the IA-32 and DEC Alpha architectures, it has not seen active maintenance since 2002 and is no longer available for download. As of September 2020, the GNU Project does not recommend or endorse any BSD operating systems. OpenSolaris (Illumos) kernel Nexenta OS is the first distribution that combines the GNU userland (with the exception of libc; OpenSolaris' libc is used) and Debian's packaging and organisation with the OpenSolaris kernel. Nexenta OS is available for IA-32 and x86-64 based systems. Nexenta Systems, Inc initiated the project and sponsors its continued development. Nexenta OS is not considered a GNU variant, due to the use of OpenSolaris libc. Multiple Illumos distributions use GNU userland by default. Darwin kernel Windows NT kernel The Cygwin project is an actively-developed compatibility layer in the form of a C library providing a substantial part of the POSIX API functionality for Windows, as well as a distribution of GNU and other Unix-like programs for such an ecosystem. It was first released in 1995 by Cygnus Solutions (now Red Hat). In 2016 Microsoft and Canonical added an official compatibility layer to Windows 10 that translates Linux kernel calls into Windows NT ones, the reverse of what Wine does. This allows ELF executables to run unmodified on Windows, and is intended to provide web developers with the more familiar GNU userland on top of the Windows kernel. The combination has been dubbed "Linux for Windows", even though Linux (i.e. the operating system family defined by its common use of the Linux kernel) is absent. See also Comparison of Linux distributions References External links Arch Hurd Superunprivileged.org GNU/Hurd-based Live CD Debian GNU/kFreeBSD Debian GNU/NetBSD #debian-kbsd on OFTC Ging live CD