Less Memory Recognised by Linux

[rajesh.bahl]

Dear All,

Need help in resolving this issue:-

Earlier it was told that UNIX does not use BIOS services.
Does linux acts the same way ?

I am having a Lenovo make PC having Intel 945 chipset  with 4 GB memory installed. Hardware setup shows 4 GB memory installed.
I installed Centos 4.4 which got  installed without problem. The issue is that the system after installation shows nearly 3 GB of memory. I later installed hugemem kernel also with the hope that balance memory can be recognised but it did not happen.Again the memory was shown as same (nearly 3 GB) despite booting with hugemem kernel.

Later I found that there are two parameters in BIOS Setup of the machine:

Memory used by OS : 3035 MB
Memory used by devices: 1061MB

Is it because of these parameters that the OS can not use memory beyond 3 GB? Is there any way to overcome this limit and use full 4 GB of memory ?


rajesh.bahl

[Ricky]

yes, most probably its your bios at fault. !

[coolpcguy]

Well it's not BIOS  fault. in order to use all of 4Gb you need 2 things- a PAE(Physical Address Extension)-enabled processor and a PAE-enabled Linux kernel. all LINUX kernels version 2.6 upwards support PAE so you have to confirm that because I DON'T know what version of kernel Cent OS is running on. if the kernel is 2.6 and above please let us know which processor do you have

[Ricky]

Well, mostly without all you explained, OS can use upto 2GB of memory only but here he said that its using 3 GB out of 4 then I guess OS is well aware of memory but BIOS is I think set to use 1/3rd part of memory for graphic etc.
..
Just a view !