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[[license text="""
Copyright © 2007 Free Software Foundation, Inc.
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.txt]].
By contributing to this page, you agree to assign copyright for your
contribution to the Free Software Foundation. The Free Software Foundation
promises to always use either a verbatim copying license or a free
documentation license when publishing your contribution. We grant you back all
your rights under copyright, including the rights to copy, modify, and
redistribute your contributions.
"""]]
IPC stands for interprocess communication.
On Unix, interprocess communication can be achieved using pipes.
This is inefficient for large amounts of data as the data must be
copied. This is generally not a problem as most services are
provided by the Unix kernel and Unix is not designed to be
[[extensible]].
[[Microkernel]] systems, on the other hand, are generally composed
of many components. As components are separated by their respective
[[address_space]] boundaries, unlike the kernel, they cannot arbitrarily
examine and modify the caller's state. The advantage is that if the
protocol is carefully designed, the callee cannot cause the caller
any [[destructive_interference]] thereby removing the need for the
caller to [[trust]] the callee thus reducing the former's [[tcb]].
When done systematically, this can increase the system's [[robustness]].
To this end, microkernels provide richer IPC semantics that include
the ability to transfer [[capabilities|capability]] and to use [[virtual_memory]]
[[mechanism]]s to copy data.
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