lubuntu-desktop team mailing list archive

[Jonathan Marsden <jmarsden@xxxxxxxxxxx>]

On 11/20/2011 07:29 AM, Chow Loong Jin wrote:

> On 20/11/2011 19:31, Yorvyk wrote:


>> If a CPU can't support PAE it can't support more than 4GiB of RAM,
>> so the PAE part of the kernel shoudn't come into play.

 

> From what I understand, PAE has a different set of paging structures
> compared to non-PAE. Does the kernel know to fall back onto non-PAE
> mode if it cannot enable PAE on a CPU?


Which way to do things is basically a compile time option for the
kernel, as I understand it.  So, if a PAE kernel is used, it can *only*
be run on processors that support the additional PAE instructions.  Even
if a machine only has 128MB RAM, it you try to run a PAE kernel on it,
and the CPU lacks the PAE instruction, it is not going to run.

The real question is: are there really any CPUs in general purpose
desktops or laptops, in any significant quantity at all, that Ubuntu
11.10 i386 kernels work on, which PAE kernels do not work on?

Other than the early 400MHz Pentium-M, which are pretty rare, I don't
think anyone has seen such a CPU yet.  Via C3 and AMD Geode LX already
cannot run current Ubuntu 11.10 default kernels anyway.

Jonathan