Ger <No.### [at] ThankYou> wrote:
> Chambers wrote:
> > Been there, done that, crashed my PC at 2Gb utilized by POV-Ray alone :)
> >
> > Note to self: 3Gb in your system doesn't get around the fact that most
> > XP programs are only able to address 2...
> >
> Addendum to note: Having 8GB in your system doesn't prevent Povray from
> still having to use the swap space.

you guys are nuts! :P

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Chambers, Ger:

Thanks for that information. I thought until now, the operating system 
handles the RAM, and the programs just forward their RAM requests to Windows 
which would give them, what they need.

I don't knew that programs self address the RAM.

Bad to hear that software developers don't want to work with higher RAM 
addresses. Thought, if RAM is available, the programs could reach it 
dynamically, independent from intented borderlines (2 GB).

Thanks for the information, greetings,

Sven



"Chambers" <ben### [at] pacificwebguycom> schrieb im Newsbeitrag 
news:47a172b4@news.povray.org...
> nemesis wrote:
>> "Sven Littkowski" <sven [] jamaica-focus [] com> wrote:
>>> You passed the crash borderline and are on unknown ground now.
>>
>> Corageosly going where no other raytracer ever dared...
>>
>>> That will
>>> become the mother of all photon map files!
>>
>> ah, the 1 GB photon map!
>
> Been there, done that, crashed my PC at 2Gb utilized by POV-Ray alone :)
>
> Note to self: 3Gb in your system doesn't get around the fact that most XP 
> programs are only able to address 2...
>
> -- 
> ...Ben Chambers
> www.pacificwebguy.com

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Sven Littkowski wrote:
> Bad to hear that software developers don't want to work with higher RAM 
> addresses. Thought, if RAM is available, the programs could reach it 
> dynamically, independent from intented borderlines (2 GB).

The issue is that the numbers used to address memory get too big for the
processor to handle. 32-bit pointers simply cannot reference memory
beyond 4 GB -- you need a 64-bit processor with a 64-bit operating
system and 64-bit applications to go beyond that.

Now, I may be wrong, but my understanding is that the 32-bit version of
Windows XP can't use more than 2GB *total* for the entire system.
(That's 4 GB minus 2 GB worth of addresses hard-coded in to refer to
hardware peripherals...) Microsoft helpfully released a patch that makes
memory beyond 2 GB show up as available in the information pane, but XP
still can't actually use it. :-D

Vista can handle 4 GB just fine, but that is offset by the operating
system itself using twice as much memory...

(Nice time to switch to Linux, BTW. We've had a 64-bit version of the OS
available much longer than Microsoft, and have had time to work most of
the compatibility kinks out!)

-- 
William Tracy
afi### [at] gmailcom -- wtr### [at] calpolyedu

You know you've been raytracing too long when all your browser bookmarks
have something to do with raytracing.
    -- Taps a.k.a. Tapio Vocadlo

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"Sven Littkowski" <sven [] jamaica-focus [] com> wrote:

> Chambers, Ger:
> 
> Thanks for that information. I thought until now, the operating system
> handles the RAM, and the programs just forward their RAM requests to
> Windows which would give them, what they need.
> 
> I don't knew that programs self address the RAM.
> 
> Bad to hear that software developers don't want to work with higher RAM
> addresses. Thought, if RAM is available, the programs could reach it
> dynamically, independent from intented borderlines (2 GB).
> 
> Thanks for the information, greetings,
> 
> Sven
> 
> 

Sven,

I think you have things mixed up. Any modern program lets the operating
system handle the memory. For a program to bypass the OS and try and do the
memory management itself is a sure way to disaster.
The difference is that the older Windows versions don't access anything
above 3GB because they can't address it. It's out of their range. The newer
versions do address it, and in my case with 64bit linux 2^128 bytes is the
theoretical limit (340282366920938463463374607431768211456 which is a LOT).
Having programs go for the "higher" ram addresses is old style DOS
programming.

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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> 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
>

Post a reply to this message

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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