> Note to self: 3Gb in your system doesn't get around the fact that most 
> XP programs are only able to address 2...
> 

I think there is a way to make it address up to 3GB; but if you have 
4GB, you can't use it all unless you have a 64-bit system.

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On Thu, 31 Jan 2008 14:43:59 -0200, Nicolas Alvarez wrote:

> I think there is a way to make it address up to 3GB; but if you have
> 4GB, you can't use it all unless you have a 64-bit system.

PAE lets you get around this.

Jim

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Respect!   :-)

Sven



"Ger" <No.### [at] ThankYou> schrieb im Newsbeitrag 
news:47a1f485@news.povray.org...
> And as an aside, I do have 8GB RAM and 12GB swap and still manage to have
> povray crash with an "out of memory" error :)
>
> -- 
> Ger

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Please more information on PAE. I would be very interested to hear your 
experiences with it. And a link (but i am gonna search for it now, too).

Thanks!

Sven



"Jim Henderson" <nos### [at] nospamcom> schrieb im Newsbeitrag 
news:47a21a2e$1@news.povray.org...
> On Thu, 31 Jan 2008 14:43:59 -0200, Nicolas Alvarez wrote:
>
>> I think there is a way to make it address up to 3GB; but if you have
>> 4GB, you can't use it all unless you have a 64-bit system.
>
> PAE lets you get around this.
>
> Jim
>

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On Thu, 31 Jan 2008 22:57:27 -0500, Sven Littkowski wrote:

> Please more information on PAE. I would be very interested to hear your
> experiences with it. And a link (but i am gonna search for it now, too).

Physical (or Paged) Address Extensions.  Wikipedia has an article on it.

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

Basically, it's very similar to the changes that led to 32-bit protected 
mode.  If you've programmed in x86 assembly, you know about 
segment:offset addressing.  PAE is a similar concept, but instead of 
using 16-bit registers, it uses 32-bit registers.  The upshot is that you 
can use it to address memory > 4 GB.

I've used it on Linux boxen that have 4 GB of memory or more (though at 
least with SUSE Linux, the PAE-enabled kernels are installed if you have 
> 2 GB of memory, and using it with less doesn't hurt anything.  I 
believe in OpenSUSE/SLE11, they're going to just use PAE kernels 
consistently as if you start with a machine with < 2 GB and then upgrade 
to > 4 GB, you need to switch out the kernel currently).

Jim
-- 
 Jim Henderson, CNA6, CDE, CNI, LPIC-1
 Novell Training Services

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Thanks, Jim. Hmm, sounds like it is made for Linux only. But let me research 
a while on Wikipedia and so on...

Sven



"Jim Henderson" <nos### [at] nospamcom> schrieb im Newsbeitrag 
news:47a2a1f3@news.povray.org...
> On Thu, 31 Jan 2008 22:57:27 -0500, Sven Littkowski wrote:
>
>> Please more information on PAE. I would be very interested to hear your
>> experiences with it. And a link (but i am gonna search for it now, too).
>
> Physical (or Paged) Address Extensions.  Wikipedia has an article on it.
>
> http://en.wikipedia.org/wiki/Physical_Address_Extension
>
> Basically, it's very similar to the changes that led to 32-bit protected
> mode.  If you've programmed in x86 assembly, you know about
> segment:offset addressing.  PAE is a similar concept, but instead of
> using 16-bit registers, it uses 32-bit registers.  The upshot is that you
> can use it to address memory > 4 GB.
>
> I've used it on Linux boxen that have 4 GB of memory or more (though at
> least with SUSE Linux, the PAE-enabled kernels are installed if you have
>> 2 GB of memory, and using it with less doesn't hurt anything.  I
> believe in OpenSUSE/SLE11, they're going to just use PAE kernels
> consistently as if you start with a machine with < 2 GB and then upgrade
> to > 4 GB, you need to switch out the kernel currently).
>
> Jim
> -- 
> Jim Henderson, CNA6, CDE, CNI, LPIC-1
> Novell Training Services
>
>

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On Fri, 01 Feb 2008 00:55:51 -0500, Sven Littkowski wrote:

> Hmm, sounds like it is made for Linux only.

No, it's a hardware-level implementation used by more than just Linux.  I 
just happen to use Linux almost exclusively, so I haven't run into it 
with other OSes.  For example, NetWare 5.1 (or maybe 6) required machines 
that had PAE functionality, even if the machine had no memory over 4 GB.

Which meant the minimum requirement was a Pentium Pro or P-II, the first 
platform that introduced PAE.  It's been around for a long time.

Jim

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Ah... Thanks, Jim. Good knowledge you got there.

But that means, ifit is not some software solution, I can't get it for my 
current system. A pity.

Thanks a lot,

Sven



"Jim Henderson" <nos### [at] nospamcom> schrieb im Newsbeitrag 
news:47a354b7@news.povray.org...
> On Fri, 01 Feb 2008 00:55:51 -0500, Sven Littkowski wrote:
>
>> Hmm, sounds like it is made for Linux only.
>
> No, it's a hardware-level implementation used by more than just Linux.  I
> just happen to use Linux almost exclusively, so I haven't run into it
> with other OSes.  For example, NetWare 5.1 (or maybe 6) required machines
> that had PAE functionality, even if the machine had no memory over 4 GB.
>
> Which meant the minimum requirement was a Pentium Pro or P-II, the first
> platform that introduced PAE.  It's been around for a long time.
>
> Jim

Post a reply to this message

On Fri, 01 Feb 2008 22:31:24 -0500, Sven Littkowski wrote:

> But that means, ifit is not some software solution, I can't get it for
> my current system. A pity.

Only if your system is a 486 or earlier.  As I said, it's in the 
hardware, you just need the software to be written to leverage it.

My original comment was in rsponse to Nicolas' statement that you'd have 
to have a 64-bit system in order to access memory over 4 GB; PAE lets you 
do that on 32-bit systems, so as long as the software is compiled for 
PAE, it can address memory > 4 GB.

Jim

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Nicolas Alvarez wrote:

>> Note to self: 3Gb in your system doesn't get around the fact that most 
>> XP programs are only able to address 2...
>>
> 
> I think there is a way to make it address up to 3GB; but if you have 
> 4GB, you can't use it all unless you have a 64-bit system.

There is a way, but it's not certain to be stable.

XP, being a 32bit OS, allows each program to address up to 4GB of 
memory.  However, this is partitioned into 2GB for the program and 2GB 
for the system.  How having more RAM (say, 3GB like in my system) helps, 
is that each individual program is really addressing a *different* 2GB 
of their own memory.  So although each only uses up to 2Gb locally, the 
total can be up to 4GB of RAM still.

The hack is to make programs think that they have 3GB, and the system 
has 1GB - but this isn't always guaranteed to work, and a lot of 
programs won't with it.

Programs that are compiled for 64bit, or are made aware of large 
addressing systems (I don't remember the MS name for the flag in the 
EXE), aren't limited like this, and will simply use whatever memory the 
system gives them.

-- 
...Ben Chambers
www.pacificwebguy.com

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