4GB memory on 32bit ? impossible ?

[Redmumba]

Physical Address Extension (PAE) is controlled by the kernel; if you're not comfortable with kernel hacking (and don't be afraid, its a nightmare your first time), then you can use the Ubuntu server kernel. The server kernel has PAE enabled by default.

sudo apt-get install linux-server linux-headers-server

Source: http://samiux.wordpress.com/2008/01/...32-bit-ubuntu/

Good luck!

[artin1982]

Physical Address Extension (PAE) is controlled by the kernel; if you're not comfortable with kernel hacking (and don't be afraid, its a nightmare your first time), then you can use the Ubuntu server kernel. The server kernel has PAE enabled by default.



Source: http://samiux.wordpress.com/2008/01/...32-bit-ubuntu/

Good luck!

Thanks but I think you didn't read my first post ...
I said I used server kernel and I also compiled kernel from kernel.org with PAE enabled ! but none of them are working

I've read all of these links before posting my question ...

[artin1982]

I think its my MB/Cpu problem

I tried with 64bit LiveCD and it recognized 4gb

[Redmumba]

Thanks but I think you didn't read my first post ...
I said I used server kernel and I also compiled kernel from kernel.org with PAE enabled ! but none of them are working

I've read all of these links before posting my question ...

Oops! Sorry, kind of rushed to the finish line there...

In that case, I noticed you haven't tried the "enable-pae" option through GRUB; simple append 'enable-pae' to the end of your GRUB line, see if that helps.

If not, I think you're spot on... its a motherboard issue; I hope its not a CPU issue, since PAE has been enabled since the Pentium Pro/Athlon processors!

If all else fails, 64-bit is a sure-fire way of getting that full 4GB of memory. Unless you've got a specific compatibility issue with going 64-bit, why not just take the plunge?

[dinub1]

OK. This may be a bit uneasy to visualize, but that is a known fact. 32 bit O/S's simply cannot see or access more than 4 GB of RAM.
Just imagine that the total number of memory addresses that a 32 bit O/S sees is 4 GB (2^32 bits). If you take into consideration that some adresses are already taken (mapped in memory) by peripherals, video card etc, and the O/S only can see 4 GB of RAM total, here the difference. The actual number you see as accessible memory is the free RAM Regardless if that is a Windows or Linux OS. Now if you use a 64 bit OS, that O/S can see much more memory addresses. This why if you use a 64 bit OS, it will alwways report the amount of installled RAM which in your case is 4 GB. This fact may be difficult to visulalize, but that is the way it is. It is not your motherboard or system faults, it's just a 32 bit O/S limitation that occurs in every system having 4 GB (or more) of RAM installed. If it happens that say your motherboard allows 8 GB of RAM to be installed, and you have that on your system, a 32 bit O/S will not report more than say over 3 GB of RAM, even if you know that physically you have more.

[artin1982]

I think I've found the problem !

in my grub line I have this option "vga=788" , seems its related to ATI driver ...
After removing it surprisly PAE worked properly !
but I had problem with 3D ..

no matter because I am changing my motherboard next week and the new motherboard will have the new Intel onboard graphic card ( 4500 series )


thanks everybody !

[Warren North]

Only problem I found so far in compatibility problems with the 64 bit Ubuntu. Even Windows 64 Bit will only run 64 bit programs I think?.
I do not think a lot is written yet for 64 bit. I feel I been better off waiting because when I used 64 bit Ubuntu it worked but it did not work with anything on my machine and I was stuck all the time. But I got to use 3.8 GB rather than 3.2. I just got over it and like running 3.2 with the 32 bit because it is much smoother. Unless being efficient is that important.

[artin1982]

Only problem I found so far in compatibility problems with the 64 bit Ubuntu. Even Windows 64 Bit will only run 64 bit programs I think?.
I do not think a lot is written yet for 64 bit. I feel I been better off waiting because when I used 64 bit Ubuntu it worked but it did not work with anything on my machine and I was stuck all the time. But I got to use 3.8 GB rather than 3.2. I just got over it and like running 3.2 with the 32 bit because it is much smoother. Unless being efficient is that important.

I think there are 2 problems ,
1-there is stability problem with some softwares and some of them doesn't support 64bit ..
2-number of 64bit users and developers and much less than 32bit users ... in 32bit when there is a bug many user will report it and there are many developers that will fix bugs very soon .. for example there was a bug in wine 64bit and it took about 2-3 months that they fixed it completely !

now I again checked and I see following mem report using 4GB in 32bit with PAE:

#free -m
             total       used       free     shared    buffers     cached
Mem:          4052        646       3406          0         60        316
-/+ buffers/cache:        270       3782
Swap:         3906          0       3906

3.95GB is it ok ?

[jacksaff]

There is no 64bit problem with linux.
Everything in the repositories (ie. a lot) is compiled to run on 64bit and there are libraries you can install that let 64bit linux run binaries compiled for a 32bit system (ia32libs from memory but I'm not sure).
Even flash plugins work fine in 64bit now. There really is no reason not to use it.
PAE will cause you more problems than using a 64bit distro.

[forger]

how can i find that cpu support PAE or no ?

I think the flag "pae" shows that:

cat /proc/cpuinfo | grep 'pae'

If it shows the "flags" line, then your processor probably supports PAE