GNU Mach is not the most advanced microkernel known to the planet,
nor is it the fastest or smallest, but it has a rich set of interfaces and
some features which make it useful as the base of the Hurd system.
- it's free software
- Anybody can use, modify, and redistribute it under the terms of the GNU
General Public License (see Copying). GNU Mach is part of the GNU
system, which is a complete operating system licensed under the GPL.
- it's built to survive
- As a microkernel, GNU Mach doesn't implement a lot of the features
commonly found in an operating system, but only the bare minimum
that is required to implement a full operating system on top of it.
This means that a lot of the operating system code is maintained outside
of GNU Mach, and while this code may go through a complete redesign, the
code of the microkernel can remain comparatively stable.
- it's scalable
- Mach is particularly well suited for SMP and network cluster techniques.
Thread support is provided at the kernel level, and the kernel itself
takes advantage of that. Network transparency at the IPC level makes
resources of the system available across machine boundaries (with NORMA
IPC, currently not available in GNU Mach).
- it exists
- The Mach microkernel is real software that works Right Now.
It is not a research or a proposal. You don't have to wait at all
before you can start using and developing it. Mach has been used in
many operating systems in the past, usually as the base for a single
UNIX server. In the GNU system, Mach is the base of a functional
multi-server operating system, the Hurd.