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How much memory can a 32-bit kernel address?

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Hemant Shah

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Oct 19, 2007, 12:47:25 PM10/19/07
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I have a 32-bit system with 4GB of memory.
How much more memory can I add to it?

Thanks.


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ray

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Oct 19, 2007, 1:07:02 PM10/19/07
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On Fri, 19 Oct 2007 16:47:25 +0000, Hemant Shah wrote:

>
> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?
>
> Thanks.

As memory serves, I believe you could add 60gb - you might want to check
wikipedia for details.

[H]omer

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Oct 19, 2007, 1:39:18 PM10/19/07
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Verily I say unto thee, that Hemant Shah spake thusly:

> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?
>
> Thanks.

In a 32 bit system, normally you will be limited to 4GB unless your
kernel was compiled with the flag:

CONFIG_HIGHMEM64G=y

This is not an issue on 64 bit systems running a 64 bit kernel.

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Jean-David Beyer

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Oct 19, 2007, 1:45:26 PM10/19/07
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Hemant Shah wrote:
> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?
>
> Thanks.
>
>
I have a 32-bit system with 8 GBytes of memory. If I used 2 GByte memory
modules instead of the 1 GByte modules I have, I could go up to 16 GBytes.
That is the limit of the motherboard.
The Intel E7501 chipset allows me to go to 64 GBytes. I have 32-bit Xeon
processors. I run the kernel-PAE-2.6.18-8.1.14.el5 from Red Hat.

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alt

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Oct 19, 2007, 1:53:42 PM10/19/07
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On Fri, 19 Oct 2007 16:47:25 +0000, Hemant Shah wrote:


> I have a 32-bit system with 4GB of memory. How much more memory can I
> add to it?
>
> Thanks.


I think you're at the limit. 32bits all set to one is about 4096MB (4GB)

spi...@freenet.co.uk

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Oct 19, 2007, 2:10:27 PM10/19/07
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In the sacred domain of comp.os.linux.advocacy,
Hemant Shah <sh...@typhoon.xnet.com> didnst hastily scribble thusly:

> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?

I *think* the limit is 36 gigs.
(you need to enable PAE (paged address extension) in the kernel)
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| |can't move, with no hope of rescue. |
|Andrew Halliwell BSc(hons)|Consider how lucky you are that life has been |
| in |good to you so far... |
| Computer Science | -The BOOK, Hitch-hiker's guide to the galaxy.|

Chris Cox

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Oct 19, 2007, 4:00:54 PM10/19/07
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You're forgetting PAE memory access. Allows you to do page indirect
accesses to handle memory beyond what is allowable by straight
access.


http://en.wikipedia.org/wiki/Physical_Address_Extension

Message has been deleted

Hans-Peter Diettrich

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Oct 19, 2007, 6:09:44 PM10/19/07
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Hemant Shah wrote:

> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?

This depends on both your hardware (RAM slots, memory management...) and
kernel software. Usually the hardware imposes the stricter limit.

DoDi

graeme

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Oct 19, 2007, 9:12:33 PM10/19/07
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On Fri, 19 Oct 2007 16:47:25 +0000, Hemant Shah wrote:

> I have a 32-bit system with 4GB of memory. How much more memory can I
> add to it?

64GB max on x86 with correctly configured vanilla kernel IIRC. Your
motherboard won't go that high.

The Ghost In The Machine

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Oct 19, 2007, 2:05:21 PM10/19/07
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In comp.os.linux.advocacy, Hemant Shah
<sh...@typhoon.xnet.com>
wrote
on Fri, 19 Oct 2007 16:47:25 +0000 (UTC)
<ffan2t$8os$2...@new7.xnet.com>:

>
> I have a 32-bit system with 4GB of memory.
> How much more memory can I add to it?

Need a little more info. If you're running on a Xeon/PAE,
apparently you can have up to 64 gigabytes, even on a
32-bit architecture, through use of the Physical Address
Extension (PAE).

http://www.sybase.com/detail?id=1030009

Try

$ grep pae /proc/cpuinfo

to see if you have the PAE bit set, and therefore can access
more than about 4 GB of RAM.

http://osdir.com/ml/admin.managers/2003-05/msg00042.html

is a thread that may have some relevant information for you,
relating to the PAE extension, which apparently the
thread thinks is similar to the EMS extension, long ago
(I can't say, I for one do not have it). Therefore, there
will be a performance hit.

>
> Thanks.
>
>


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