does anyone write a built-in kernel GUI in linux

Question

Process switch between X server and X client might cost much when drawing, especially in embedded system. I am writing a built-in kernel GUI in linux based on the kdrive Xfree86-4.5.0 version(primaryly using their drawing routines). I intend to apply serveral sys call in kernel, and X lib call them to draw on screen, thus I need not to rewrite X clients. I have finished card, screen initialization part and it seems not difficult as I thought. Now, I am wondering why other one did not do it, afraid of bigger kernel? or other performance will reduce? is there any one have thought such problems and can give me reasons? I will be appreciated for any discuss on this topic.

Roberto Waltman · Accepted Answer

The "pros" of including the graphics/GUI portions of an operating system are, as you pointed correctly, better performance.

Every other aspect I can think of is a "con": larger kernel, more difficult to update/replace the GUI functionality, kernel reliability depending on GUI, or even less performance, if the GUI software interferes with the kernel scheduling mechanism.

For you information, the GUI was an external layer in the first few versions of the Windows NT kernel. It was moved into the kernel around version 4 (to improve performance) and remained there for later versions of Windows 2000 and XP. Now that computers are much faster, and some of the functionality is implemented in hardware, they are doing the right thing and taking it out again.

See:

formatting link

I believe in the Beos system the GUI is part of the kernel also. (not sure) Same goes for the hobby projects Atheos/Syllable

Captain Dondo · Answer

Marco Cavallini · Answer

>> Process switch between X server and X client might cost much when >> drawing, especially in embedded system. >> I am writing a built-in kernel GUI in linux based on the kdrive >> Xfree86-4.5.0 version(primaryly using their drawing routines). I intend >> to apply serveral sys call in kernel, and X lib call them to draw on >> screen, thus I need not to rewrite X clients. >> I have finished card, screen initialization part and it seems not >> difficult as I thought. >> Now, I am wondering why other one did not do it, afraid of bigger >> kernel? or other performance will reduce? is there any one have thought >> such problems and can give me reasons? I will be appreciated for any >> discuss on this topic. >> > > so why not this ;-)HTH-- Marco CavalliniKoan s.a.s. - Bergamo - ITALIAEmbedded and Real-Time Software Engineering    |

Captain Dondo · Answer

Microwindows is not in-kernel. It's a user-space app.

The OP wanted in-kernel; the only one I know of is fbui.

I think it's nuts to do that but I can see the attraction. If we were developing an app from scratch, I might be tempted to use his stuff. In fact, I looked at it seriously when we started our latest project.

Microwindows works quite well, but it's a good big bigger than fbui. I looked at it as well, but then ended up with Qt/E... Really big. :-(

--Yan

news reader · Answer

Hi,Just out of curiousity:Was it performance or features which let you finally use Qt/E... ?byeNCapta

Captain Dondo · Answer

We needed a javascript capable opensource browser.... konqueror embedded was the only one that fit those requirements, and it runs on top of Qt/e...

I'n not a big fan of Qt; it's bloated, hard to pare down, and c++ doesn't help.... But none of the other browsers had the capability we needed.

--Yan

does anyone write a built-in kernel GUI in linux

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