GNU Hurd

GNU Hurd (usually referred to as the Hurd or just Hurd) is the multiserver microkernel written as part of GNU. It has been under development since 1990 by the GNU Project of the Free Software Foundation, designed as a replacement for the Unix kernel, and released as free software under the GNU General Public License.

GNU Hurd consists of a set of protocols and server processes (or daemons, in Unix terminology) that run on the GNU Mach microkernel. The Hurd aims to surpass the Unix kernel in functionality, security, and stability, while remaining largely compatible with it. The GNU Project chose the multiserver microkernel for the operating system, due to perceived advantages over the traditional Unix monolithic kernel architecture.

Name and logo

In December 1991 the primary architect of the Hurd described the name as a mutually recursive acronym:

As both hurd and hird are homophones of the English word herd, the full name GNU Hurd is also a play on the words herd of gnus, reflecting how the kernel works. The logo is called the Hurd boxes and it also reflects on architecture. The logo is a graph where nodes represent the Hurd kernel's servers and directed edges are IPC messages.