I have a question about standard output. I have a camkes component than can write into text-mode VGA buffer (basically it follows this simple example http://wiki.osdev.org/Bare_Bones#Writing_a_kernel_in_C ) but I would like to be able to redirect the kernel messages during startup to be printed on screen using VGA buffer.

Once another component (either Linux in a VM, or some other camkes app) will initialize, it will be able to take control over the screen output (and for example show login window etc). 

My questions is - is this possible with seL4? And if so, what would it entail? 

I guess in the minimal version, I would have to provide a different implementation of seL4_DebugPutChar, is that correct? 

The VGA standard seems to define the buffer to be at 0xB8000, so it should be consistent between x86 platforms.

Regards

Michal