Re: Sigma1

Hello,

The microkernel needs memory resources for page tables, TCBs, and  
mapping nodes.  We give the kernel a reserved set of pages for its  
memory demands.  But of course the kernel can deplete its reserved  
set of pages, and since it is a microkernel, it has no logic to swap  
applications to disk to reclaim their pages.  Sigma1 is a memory  
server that helps the kernel obtain more memory; sigma1 is  
responsible for taking pages from the other applications and handing  
the pages back to the kernel.  This has not been implemented yet.  An  
alternative approach was created by Andreas Haeberlen, where the  
applications provide to the kernel the resources necessary for  
creating children applications.

-Josh


On May 20, 2006, at 17:55 , Luke A. Guest wrote:

> Hi,
>
> I've just started to look at L4 and I'm using L4ka::Pistachio as a
> starting point. I'm trying to read as much as possible and have  
> found a
> reference to sigma1, but no docs on it. Can anyone elaborate on what
> this is for?
>
> Thanks,
> Luke.
>
>
>