dennis;738953 Wrote:
Applications don't address physical memory, they only access their
virtual address space. So it doesn't matter where in physical ram an
application's virtual address space points to. It can be below or above
4G, it doesn't matter.

Dennis, You have absolutely no idea what your talking about do
you?...Please stop wasting yours and our time talking such complete
rubbish.

I have never heard so much bull****.

dmex


--
dmex

*'' (http://www.VistaX64.com)
*

If you want to argue that PAE is treated as a value-added item and therefore
Marketing decided to "withhold" some of its functionality from Windows
clients for price differentiation purposes, go ahead. They do that stuff
all the time. That's why the Snipping Tool isn't in Vista Home Basic.
However I personally don't think there was anything like that decision
making involved with PAE.

PAE showed up around 8 years ago, if I remember correctly. Think back to
what Windows client computers were back then. A typical consumer box at
Best Buy or Comp USA was going out the door with WinME and 128mb of ram with
mobos whose memory controllers were limited to 512mb of ram. The hardware
simply didn't support any more. DDR hadn't even shown up.

By late 2001 machines were being sold with XP Home and 256mb of ram. It
cost the buyer a couple of hundred bucks to upgrade to 512mb and mobos with
three memory slots did not support anything more than 768mb. The four-slot
ones could support 2GB but 512mb memory sticks were horribly expensive and
machines usually sold with 256mb (two sticks). A few folks added more.

While all this was going on Enterprise class server boxes that could support
4+GB cost between $10k and $20k. The push for 4+GB was coming from medium
and large enterprises with large SQL and Exchange loads. Enter PAE (there
were other schemes as well). MS was not solving a general problem with PAE.
They were addressing a need expressed by enterprise users. So they
developed Windows 2000 Advanced Server and all later Enterprise server
editions to enable PAE if needed. There wasn't a need to address the issue
on the client side. So why would they?

When Intel developed the data execution bit for the later Pentium 4s in
order to support DEP it turned out that PAE could also address a conflict
sometimes encountered with DEP. That's when MS wrote PAE support into the
service packs that were releasing for W2k and XP. But only to address the
problem. Folks weren't running desktops with 4GB of memory at that time,
much less ones with more than 4GB. However, workstation users were and
that's when MS wrote XP Pro x64 to address that memory need. I don't think
MS has ever considered PAE as a suitable solution for consumers and
workstation users in addressing memory needs. There can be a perf hit with
it and I think the judgement to provide 64bit consumer operating systems
like Vista was the better choice.

"dennis" wrote in message
...
Colin Barnhorst wrote:
Where do you get the idea that MS chose not to let the clients "go
there." They inherently don't "go there." The only "choice" MS made was
to program a capability into the Windows Server editions that enables
them to "go there." The capability to enable PAE to leverage additional
addressable memory is something that has to be programmed into an OS, not
something that is programmed out of one.

Okay, again. You said it yourself: both xp and vista comes with a PAE
kernel, to support DEP.

When you enter PAE mode the CPU makes it both mathematically and
technically possible to address more than 4GB. So now the OS developer has
a *choice*. Microsoft choose *not* to support more than 4GB in the PAE
kernel (starting from XP/SP2), because there exist bad drivers out there.
*This* is what we're talking about, at least I am.

dmex wrote:

Dennis, You have absolutely no idea what your talking about do
you?...Please stop wasting yours and our time talking such complete
rubbish.

I have never heard so much bull****.

Come again?

It is a nice story, but still not what we are talking about. We are
talking about what is technically possible. And the fact is, you can
address more than 4GB in PAE mode. Microsoft just choose not to do so in
XP/SP2 and Vista.

Colin Barnhorst wrote:
If you want to argue that PAE is treated as a value-added item and
therefore Marketing decided to "withhold" some of its functionality from
Windows clients for price differentiation purposes, go ahead. They do
that stuff all the time. That's why the Snipping Tool isn't in Vista
Home Basic. However I personally don't think there was anything like
that decision making involved with PAE.

PAE showed up around 8 years ago, if I remember correctly. Think back
to what Windows client computers were back then. A typical consumer box
at Best Buy or Comp USA was going out the door with WinME and 128mb of
ram with mobos whose memory controllers were limited to 512mb of ram.
The hardware simply didn't support any more. DDR hadn't even shown up.

By late 2001 machines were being sold with XP Home and 256mb of ram. It
cost the buyer a couple of hundred bucks to upgrade to 512mb and mobos
with three memory slots did not support anything more than 768mb. The
four-slot ones could support 2GB but 512mb memory sticks were horribly
expensive and machines usually sold with 256mb (two sticks). A few
folks added more.

While all this was going on Enterprise class server boxes that could
support 4+GB cost between $10k and $20k. The push for 4+GB was coming
from medium and large enterprises with large SQL and Exchange loads.
Enter PAE (there were other schemes as well). MS was not solving a
general problem with PAE. They were addressing a need expressed by
enterprise users. So they developed Windows 2000 Advanced Server and
all later Enterprise server editions to enable PAE if needed. There
wasn't a need to address the issue on the client side. So why would they?

When Intel developed the data execution bit for the later Pentium 4s in
order to support DEP it turned out that PAE could also address a
conflict sometimes encountered with DEP. That's when MS wrote PAE
support into the service packs that were releasing for W2k and XP. But
only to address the problem. Folks weren't running desktops with 4GB of
memory at that time, much less ones with more than 4GB. However,
workstation users were and that's when MS wrote XP Pro x64 to address
that memory need. I don't think MS has ever considered PAE as a
suitable solution for consumers and workstation users in addressing
memory needs. There can be a perf hit with it and I think the judgement
to provide 64bit consumer operating systems like Vista was the better
choice.

Dennis, Colin's original statement was right, it is mathematically
impossible to address more using 32 bits. It is possible using 32 bits
AND something else to physically achieve what "Looks like" addressing
more but this is by ADDING something - the limit is real if nothing
extra is added.

The Commodore 64 really had 64K, but also a 32K ROM BASIC and a IIRC 2K
which today we might call an OS or BIOS.

64K WAS the physical limit, but the ROM overlaid it and could be turned
off, which we did all the time to load games. I personally wrote
software that could both use the BASIC and page it our for storage, then
back in again for use. But I could NOT use BASIC routines and the
underlying RAM at the same time.

So I think we are down to semantics here where nobody is actually
"Wrong" but disagree about descriptions. I never owned a 96K Commodore
but was able to use more than 64K.

Note Colin's mention somewhere here of a "Performance Hit", that is why.


dennis wrote:
It is a nice story, but still not what we are talking about. We are
talking about what is technically possible. And the fact is, you can
address more than 4GB in PAE mode. Microsoft just choose not to do so in
XP/SP2 and Vista.

Colin Barnhorst wrote:
If you want to argue that PAE is treated as a value-added item and
therefore Marketing decided to "withhold" some of its functionality
from Windows clients for price differentiation purposes, go ahead.
They do that stuff all the time. That's why the Snipping Tool isn't
in Vista Home Basic. However I personally don't think there was
anything like that decision making involved with PAE.

PAE showed up around 8 years ago, if I remember correctly. Think back
to what Windows client computers were back then. A typical consumer
box at Best Buy or Comp USA was going out the door with WinME and
128mb of ram with mobos whose memory controllers were limited to 512mb
of ram. The hardware simply didn't support any more. DDR hadn't even
shown up.

By late 2001 machines were being sold with XP Home and 256mb of ram.
It cost the buyer a couple of hundred bucks to upgrade to 512mb and
mobos with three memory slots did not support anything more than
768mb. The four-slot ones could support 2GB but 512mb memory sticks
were horribly expensive and machines usually sold with 256mb (two
sticks). A few folks added more.

While all this was going on Enterprise class server boxes that could
support 4+GB cost between $10k and $20k. The push for 4+GB was coming
from medium and large enterprises with large SQL and Exchange loads.
Enter PAE (there were other schemes as well). MS was not solving a
general problem with PAE. They were addressing a need expressed by
enterprise users. So they developed Windows 2000 Advanced Server and
all later Enterprise server editions to enable PAE if needed. There
wasn't a need to address the issue on the client side. So why would
they?

When Intel developed the data execution bit for the later Pentium 4s
in order to support DEP it turned out that PAE could also address a
conflict sometimes encountered with DEP. That's when MS wrote PAE
support into the service packs that were releasing for W2k and XP.
But only to address the problem. Folks weren't running desktops with
4GB of memory at that time, much less ones with more than 4GB.
However, workstation users were and that's when MS wrote XP Pro x64 to
address that memory need. I don't think MS has ever considered PAE as
a suitable solution for consumers and workstation users in addressing
memory needs. There can be a perf hit with it and I think the
judgement to provide 64bit consumer operating systems like Vista was
the better choice.

dennis wrote:
SCSIraidGURU wrote:
You can only access a theoretical maximum of 4GB in 32-bit OS. Most
computers are lucky to address 3.25 GB with newer video cards installed.
64-bit Ultimate can address 128GB of RAM and huge paging file. /pae
switch does not allow you to break the 4GB 32-bit rule. I used it to
help NUMA memory management on my AMD server boards.
2^ 32 =4294967296
=4GB

I suspect that you don't know fully how memory access works in a x86 cpu
running in paging mode. The only thing that cannot change is the size of
the virtual address space, which is always 4GB. The physical one can be
much larger.

Btw, 32bit xp/vista supports up to 16TB per paging file when the PAE
kernel is loaded.


Yes but that is paging, and there will be a performance hit because you
can't suddenly yank the rug (OS) from under the CPU.

Charlie Tame wrote:
Dennis, Colin's original statement was right, it is mathematically
impossible to address more using 32 bits. It is possible using 32 bits
AND something else to physically achieve what "Looks like" addressing
more but this is by ADDING something - the limit is real if nothing
extra is added.

Note Colin's mention somewhere here of a "Performance Hit", that is why.


PAE mode adds another layer to the page table, and extends it from 32 to
64 bits. This allows for more than 32 bit to be used for addressing
memory. So it is very mathematically possible to address more than 4GB.

The "performance hit" is very small. Most people are already running in
PAE mode, due to DEP support.

Charlie Tame wrote:

Yes but that is paging, and there will be a performance hit because you
can't suddenly yank the rug (OS) from under the CPU.

Windows only runs in one mode: paging mode. Thus, the OS needs to supply
the CPU with a page table to lookup the physical address. What PAE does
is to change the layout of this table.

dennis wrote:
Charlie Tame wrote:
Dennis, Colin's original statement was right, it is mathematically
impossible to address more using 32 bits. It is possible using 32 bits
AND something else to physically achieve what "Looks like" addressing
more but this is by ADDING something - the limit is real if nothing
extra is added.

Note Colin's mention somewhere here of a "Performance Hit", that is why.


PAE mode adds another layer to the page table, and extends it from 32 to
64 bits. This allows for more than 32 bit to be used for addressing
memory. So it is very mathematically possible to address more than 4GB.

The "performance hit" is very small. Most people are already running in
PAE mode, due to DEP support.


Yes, I am just saying there are bigger fish to fry and I think there is
nitpicking but no real argument... been there done that (with you) and
it really does not help anyone. We all face a bigger problem with ISPs
now. FWIW I think Microsoft has done a good job trying to stay impartial
and an even better job at keeping the business in friendly territories....

Applications use both Physical RAM and Paging file. You can disable all
paging and still get programs to function. Applications like many A/V
and CAD apps will not work without paging to swap pages with. The
paging file in Vista does more than just virtual memory.


--
SCSIraidGURU

Michael A. McKenney
'www.SCSIraidGURU.com' (http://www.SCSIraidGURU.com)

Supermicro X7DWA-N server board
pair of Intel E5430 quad core 2.66 GHz Xeons
16GB DDR667
SAS RAID
eVGA 8800 GTS 640 MB video card