[[!meta copyright="Copyright © 2007, 2008, 2010, 2012, 2013, 2014 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU Free Documentation License|/fdl]]."]]"""]] A *microkernel* is one kind of a [[kernel]] implementation. [[Liedtke]] explains in [On Microkernel Construction](http://l4ka.org/publications/paper.php?docid=642) (or from [TU Dresden](http://www.tud-os.org/papers_ps/jochen/Mikern.ps), or from [ACM](http://dl.acm.org/citation.cfm?id=224075)) that a microkernel attempts to minimize the mandatory part of the operating system by providing the minimal number of [[mechanism]]s that maximize the flexibility of implementation (by imposing minimal [[policy]]) while allowing the efficient implementation of the remainder of the system. The idea of a microkernel as explained above was first explored by Per Brinch-Hansen in 1970 in [The Nucleus of a Multiprogramming System](http://brinch-hansen.net/papers/1970a.pdf). An [introduction](http://www.cs.cornell.edu/Info/People/ulfar/ukernel/ukernel.html) by Úlfar Erlingsson and Athanasios Kyparlis (from 1996) to microkernel concepts. [[Research]]. [[faq/Multiserver_Microkernel]]. [[Microkernels_for_beginners|for_beginners]]. A 2002 article about [[microkernel_FUD|FUD]] (Fear, Uncertainty, Doubt). # Implementations * [[Hydra]] * [[KeyKOS]] * [[Mach]] -- used by the GNU/Hurd * [[EROS]] * [[CapROS]] * [[Coyotos]] * [[L4]] * [[Barrelfish]] * [[Viengoos]] * [[Genode]]