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Re: Added more memory. Not useable???

On Sun, 3 May 2009 08:28:44 +0300
Andrei Popescu <andreimpopescu@gmail.com> wrote:

> On Sat,02.May.09, 15:27:26, Mark Neidorff wrote:
> > > Same thing, the kernel doesn't recognize your memory. What kernel
> > > flavour are you running (uname -a)?
> > Linux mail 2.6.18-6-486 #1 Fri Dec 12 16:18:30 UTC 2008 i686 GNU/Linux
> Ok, I would try the -686 flavour and the -686-bigmem flavours. The 
> -bigmem flavour should not be needed unless you have *more* than 4GB 
> RAM, but it's worth experimenting with.

Actually if I'm not mistaken more the 2gb or 3gb (not sure about the standard
setup). Theoretically standard 32bit can address 4gb but the kernel splits that
memory space between userspace and kernel space, classically in a 2gb:2gb
split, which leaves 2gb addressable memory. It is possible to set it up in a
3gb:1gb split, but it is not standard.

Bigmem uses an extention that allows addressing more memory (I think that it's
called pxe). Another option is to use a 64bit kernel, but unless you use a
64bit userspace a few things can cause problems (most things work ok, I think
except some modules). The only problem with a 64bit userspace is more memory
consuption by programs (about 15%). Performace may also vary, depending on
typical usage.

> Regards,
> Andrei

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