Re: Using 4gig PAE Capability

[Sven Hartge <sven@svenhartge.de>]

David Baron <d_baron@012.net.il> wrote:

> This is apparently not at all a rare problem. I put 4gig in my
> computer but it only recognizes 3gig.

Please post the output of

  dmesg | grep BIOS-e820

This will show the memory map provided by the BIOS.

> Is there any way for the kernel to bypass/override BIOS and see all
> the memory?

The "lost" or "missing" memory is not directly reachable because it is
shadowed by the PCI address space.

The only way to be able to access this hidden memory is if the board is
able to remap that memory region to a different place, in most (all?)
cases beyond the 4GiB limit. If and only if this is possible, you are
able to use PAE to access this memory region.

Many older boards lack this function inside the BIOS or are even unable
because of hardware constraints, either by design or by choice of the
manufacturer.

Grüße,
Sven.

-- 
Sigmentation fault. Core dumped.