(* = offsite link)
- What is L4?
- Originally, L4 is the name of a second-generation µ-kernel
(microkernel) designed and implemented by
running on i486 and Pentium CPUs.
However, there are now numerous
implementations of the L4 API
(application programming interface)
on several hardware architectures. That's why, on this website
we usually refer to the ``L4 µ-kernel interface'' (see
When we refer to Jochen's
original implementation, we say
- What is a µ-kernel?
- Please refer
to the corresponding entry in the Fiasco FAQ.
- What is the L4 µ-kernel interface?
- It is a definition of an API for µ-kernels.
Kernels based on the L4 API are second-generation µ-kernels.
They are very lean and feature fast, message-based, synchronous
IPC, simple-to-use external paging mechanisms, and a security mechanism
based on secure domains (tasks, clans and
chiefs). The kernels try to implement only a minimal set of
abstractions on which operating systems can be built flexibly.
- What implementations of the L4 µ-kernel interface do
- There are implementations for x86, Alpha, ARM, and R4x00 CPUs.
Please see the implementations page for
- What is L3?
is a microkernel implementation running on x86 CPUs. It is
a predecessor to L4/x86. It is not compatible with L4.
- Developers welcome!
- Please consider subscribing to our public developer's mailing list at
(use "subscribe" in the message
The discussion language for this mailing list is
Before posting to the mailing list, you may want to check out the mailing
list archive and the FAQs for the various kernel implementations.
Last modified: Mon Jul 23 13:51:13 2001