In the second scenario, the Qt port to the L4/Fiasco microkernel is presented. Qt is a wildly-used open source GUI-toolkit and builds for example the base of the K Desktop Environment (KDE). The port is fairly complete and makes it possible to run many Qt applications natively on L4. To demonstrate this feature, you can watch pictures with the Qt image viewer QVV or play the freaky Qt-based game Little Sheep in the tutorial.
With the GRUB bootloader of the TUD:OS live CD you select one of the diffrent demo setups you want to try out.
Scenario 3: L4Linux - A virtualized Linux on a componentized, small kernel system
A development, which impresses me very much is the L4 adaptation of the Linux kernel in a way that it can be executed as a L4/Fiasco user task. This adjusted L4Linux is binary compatible with the common Linux/x86 kernel and facilitates running Linux programs without any changes in parallel with highly secure L4 applications or real-time tasks with time constraints to be guaranteed. Of course, you can also run many L4Linux instances one your system, which all cannot influence each other since every user task has its own secure address space.
Unfortunately, the L4Linux instances you can invoke in this tutorial do not come with a rich set of features (it is indeed only a command line with nothing more to do) and hence the whole scenario is a little bit boring.
Scenario 3: Driver Reuse In The L4 Environment
If you want to develop a new operating system, it would be extremely annoying to rewrite all the drivers you need for you new OS from the scratch. Therefore, the TU Dresden OS group members decided to develop a Device Driver Environment (DDE), which equips the L4/Fiasco microkernel with a driver interface wrapper to legacy OSí driver interfaces. This approach facilitates the reuse of unchanged legacy OS device drivers on source-code level. A DDE exits for Linux device drivers and the work on a FreeBSD DDE is already in progress.
A screenshot of the Nitpicker running the Scout tutorial browser, some DOpE real-time applications and the X-Window fun tool xeyes.
The rest is silence
The last two scenarios, L4VFS - L4 virtual file system layer and Trusted E-Commerce Transaction Client, shall be mentioned for the sake of completeness but are not explained here, because in my opinion they are the less interesting ones.
And now: The Evaluation
The most stunning thing about the TUD:OS demo CD to me is that you have the Scout tutorial browser explaining to you all the theoretical matters of the particular project and then - if you want to experience the things you have learned about - you simply can click on the browser and the application that was talked about will show up.
Another thing I was quite surprised of was the fact that the demo live CD worked without any problems on my laptop immediately and on all the computers that I tried to run the CD on Ė just as you would expect it for example from a Knoppix live CD. I suppose this success could be attributed to the DDE driver reusing approach. The main aspect I did not like about this demo CD was, as already explained, the practical part of the L4Linux tutorial.
Due to the L4 port of the Qt graphics library many Qt applications can be run natively on L4/Fiasco.
But please let me have some concluding words about the TUD:OS as a whole system. The way I see it, to a normal desktop computer user, the results of the TU Dresden OS groupís research process might be exciting - but they are completely useless for him in most of the cases. Whereas for a developer who wants to realize dependable real-time projects or highly secure applications, maybe even working together with conventional Linux software on the same system, the TUD:OS could be a rich pool of features on which he could base his project upon.
But if however the L4 port of the long awaited GNU/Hurd operating system will ever see its daylight and become a widespread and usable home user system, the TU Dresden OS group's developments would highly appreciate in importance in that way they could be directly used in a home desktop operating system then.
Remark: All the software of the TUD:OS projects is free software under the terms of the GNU GPL.
About the author:
I am a student of information systems technology (interdisciplinary course of studies consisting of computer science and electrical engineering) at the TU Dresden but I am not involved in any of the TUD:OS' projects right now.
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