Hurd مادر نیست! مادرش Mach نام داره:
the Hurd was developed to use GNU Mach as the microkernel
It is built on top of the Mach 3.0 kernel, a free message-passing kernel developed by CMU
Mach is just a well-known example of a microkernel architecture
An example of a mach kernel is HURD, being developed by the GNU Project since the 1980s