[rhelv6-list] RHEL6 x86 on system with 4 GB memory

[Musayev, Ilya]

Had exactly the same issue on Dell Desktop ~4 years ago (dont recall the specifics).

I upgraded the BIOS, but still it was the limitation of the BIOS to present the 4GBs to OS. After loading up PAE kernel running Fedora 6 with some tweaks, i was able to get more memory from the box. Initially i had 3.3 and it went to 3.7GB. 

Long story short, it was vendor/model specific issue for me and not so much kernel/OS.




________________________________________
From: rhelv6-list-bounces at redhat.com [rhelv6-list-bounces at redhat.com] On Behalf Of Jonathan M. Polom [s0nic0nslaught at gmail.com]
Sent: Monday, May 09, 2011 2:54 PM
To: Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list
Subject: Re: [rhelv6-list] RHEL6 x86 on system with 4 GB memory

On Tue, May 3, 2011 at 8:26 AM, Jonathan M. Polom
<s0nic0nslaught at gmail.com> wrote:
> On Tue, Apr 19, 2011 at 2:58 PM, Steve Allen
> <allen at doobie.itdl.ds.boeing.com> wrote:
>> "Jonathan M. Polom" <s0nic0nslaught at gmail.com> wrote:
>>> I have Red Hat 6 x86 installed on a Pentium 4 system with 4 GB system
>>> memory. Although the default kernel has PAE capability (no modules in
>>> lsmod but it's a requirement for the x86 variant so it's likely
>>> compiled in) it claims total system memory is about 3.3GB (via top or
>>> gnome performance monitor). How do you get RHEL6 to see >= 4GB memory?
>>> Is it a kernel argument or something else?
>>
>> PAE has to be enabled in the BIOS.  If you don't have that option in the
>> BIOS, you just can't do it.  I'm in the same position, 4GB RAM, but no
>> PAE in the BIOS, so all I get available is about 3.3GB.
>>
>> Steve
>>
>> _______________________________________________
>> rhelv6-list mailing list
>> rhelv6-list at redhat.com
>> https://www.redhat.com/mailman/listinfo/rhelv6-list
>>
>
> Didn't think to check the BIOS. Will do. Thanks.
>
> --
> Jon Polom
>

Sorry for resurrecting a dead thread but I just rechecked this issue.
The BIOS reports 4.0GB of memory installed but doesn't appear to have
an option to enable/disable PAE. So perhaps PAE isn't supported by the
BIOS? Or PAE is enabled by default. This is something I need to check
with my system vendor, however it still seems odd. Why would the BIOS
report 4.0GB of installed memory without being able to use all 4.0GB?
A colleague mentioned that it has to do with how the BIOS calculates
installed memory: installed memory size is calculated by the BIOS by
taking the difference between the highest and lowest memory addresses.
Is it typica for a BIOS to report 4.0GB (beyond the 32bit max address
without PAE) yet not support PAE?

Thanks,
Jon

_______________________________________________
rhelv6-list mailing list
rhelv6-list at redhat.com
https://www.redhat.com/mailman/listinfo/rhelv6-list