Is 4GB the max on a 32 bit OS?

[Scott Ledyard]

Thanks for the info, Gavin.

>I'm not sure if disabling devices in the BIOS might get
>you a little more RAM.

Reminds me of the days when we tried to get more than 640K!

Scott
On 1/18/07, Gavin McCullagh <gmccullagh at gmail.com> wrote:
>
> Hi,
>
> On Thu, 18 Jan 2007, Scott Ledyard wrote:
>
> > Can the x86 versions of Ubuntu (or any OS) employ more than 4GB of RAM?
>
> Probably not without a custom kernel.  Linux kernels can indeed do this,
> but I've been told that there is a considerable performance cost in doing
> so.
>         http://kerneltrap.org/node/2450
>
> I've never used the >4GB stuff myself but I believe it can be done.  one
> would want to have good reason to bother I suspect.
>
> > I read with interest how to size an LTSP server and noticed that people
> have
> > recommended lots of RAM. But, I've also heard that a 32 bit processor
> cannot
> > physically address more than 4GB of memory. True?
>
> In practice yes, for most people.
>
> Another thing to bear in mind is that if you do put 4GB RAM in a 32-bit
> machine you probably won't even be able to address the full 4GB.  The PCI
> devices are apparently mapped into the 4GB address space too.  So, there
> is
> less address space available for RAM.
>
> For example, this dell poweredge has 4x 1GB ram sticks in it:
>
> gavinmc at moodle:~$ cat /proc/meminfo
> MemTotal:      3370992 kB
> ...
>
> I guess in practice it would make no difference to put 3.5GB of ram in it
> as it seemingly can't address more than 3.4GB.  The amount used seems to
> vary from machine to machine, presumably depending on the nature and
> number
> of pci devices.  I'm not sure if disabling devices in the BIOS might get
> you a little more RAM.
>
> Gavin
>
>
> --
> edubuntu-users mailing list
> edubuntu-users at lists.ubuntu.com
> Modify settings or unsubscribe at:
> https://lists.ubuntu.com/mailman/listinfo/edubuntu-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://lists.ubuntu.com/archives/edubuntu-users/attachments/20070118/f7ee21db/attachment.htm