2

I Googled a lot about L4 microkernel and found that very less resources are there on L4.

  1. What are some good links I can refer ?
  2. Is there any application of L4 (i.e. where it is used) ?
Axel Heider
  • 557
  • 4
  • 14
Dinushan
  • 2,067
  • 6
  • 30
  • 47

3 Answers3

7

L4 supposedly passed one billion installs a year ago, so, the short answer is yes. According to my reading, Linux running on top of L4 is factors faster than running alone, making for a Linux L4, and Android has been ported to L4 on top of linux. My view, is if so many installs are running, why can't we have L4 available to us through a shell, such ksh or bash? The short answer is drivers; it was chosen for us by the L4 gods that L4 should be Linux to support drivers, even though Linux is short on drivers. There is a little about it here on this community wiki: http://alopex.li/wiki/L4FiascoTutorial And the rationale for L4/Linux here: http://www.slideshare.net/sartakov/03-advanced-components

If drivers are so problematic, such that free software prevents commercial vendors from writing them, then why not create a "qt" version for driver writers, that is to say a public domain kit that unifies computer functionality to define drivers. Then OS writers would create the backend for their OS such that the vendor only has to do the work once.

The other useful topic is the idea of a VM over L4, using Perl Parrot VM (PVM) as a hypothetical example; if L4 could be modified to run strictly in registers.... imagine the performance

johnbessa
  • 86
  • 1
  • 4
  • Actual benchmarks comparing L4/Linux vs Linux have shown that L4/Linux is far slower, which makes sense considering how it works. In addition, your idea of a generic driver kit has been done in the past, such as OSKit (and a couple successors that I can't recall). None have ever managed to gain any significant traction, due to several issues with the idea... plus, vendors have no interest in such a project unless it's already fairly successful (which is pretty hard, considering Windows, OS X, and Linux would never support such an API). You end up with a chicken and egg problem. – Kitsune Mar 18 '13 at 00:46
  • OSKit was a first L4 implementation, as I recall, in Utah in the early 2000s -- Dresden then picked up OSKit to create its proprietary L4 which resides on many if not most cell phones as a telcom subsystem-- it did so in a university environment to give the impression of open or public code -- not true: pure proprietary, I only figured this out after a while. We have an "egg" in OSKit, and the World needs to get back to it to predate Dresden's (or Adam Smith's) greed. – johnbessa Jul 30 '14 at 00:45
3

L4 is a family of microkernels sharing a more or less common API and some base ideas/concepts.

Typical applications are hard-realtime/high availability scenarios as well as a usage as hypervisor hosting more traditional operating systems.

About applications: There is an L4 kernel from ok-labs.com which was for example used in the Motorola Evoke to run the application stack side by side with the baseband stack on the same processor. A kernel from ok-labs is also used to host the baseband-stack of the iPad2.

sysgo.com has a kernel called PikeOS which they use for aerospace/defense applications.

Frank Meerkötter
  • 2,778
  • 2
  • 20
  • 26
1

According to Andrew Tanenbaum L4 is used in cell phones (fifth from last answer, or you can do a text search for "L4"). Unfortunately, I haven't managed to find much other than the L4 website, and FIASCO.

Max Lybbert
  • 19,717
  • 4
  • 46
  • 69