About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

January 3, 2008

Hy guys!

i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

installed and have read that exist a option called "/LARGEADDRESSAWARE" that

can use for improve the memory allocation for my application.

The question is : how i can enable this option ? In boot.ini as the /3G on

x86?

Thanks in advance.

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Unless I am mis-interpreting something, your information is

not entirely correct.

If you go to http://www.microsft.com and enter 'LARGEADDRESSAWARE'

in the search box you will be given links to information

indicating this is a programming option for the linker at

compile time.

InputIO wrote:

> Hy guys!

>

> i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

> installed and have read that exist a option called "/LARGEADDRESSAWARE"

> that can use for improve the memory allocation for my application.

>

> The question is : how i can enable this option ? In boot.ini as the /3G

> on x86?

>

> Thanks in advance.

>

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Hi Theo,

thanks for your reply !

I try to read some KB Articles but not understand how to enable the

"LARGEADDRESSAWARE" option.

The question is : i need edit a boot.ini file and add /LARGEADDRESSAWARE

after the sting multi(0)disk(0)rdisk(0).... ?!!?!?!

Thanks in advance.

"Theo" <theo@discussions.microsoft.com> ha scritto nel messaggio

news:Ob3rmTiTIHA.4272@TK2MSFTNGP06.phx.gbl...

> Unless I am mis-interpreting something, your information is not entirely

> correct.

>

> If you go to http://www.microsft.com and enter 'LARGEADDRESSAWARE' in the search

> box you will be given links to information indicating this is a

> programming option for the linker at compile time.

>

> InputIO wrote:

>> Hy guys!

>>

>> i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

>> installed and have read that exist a option called "/LARGEADDRESSAWARE"

>> that can use for improve the memory allocation for my application.

>>

>> The question is : how i can enable this option ? In boot.ini as the /3G

>> on x86?

>>

>> Thanks in advance.

>>

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Hi,

LARGEADDRESSWARE is not an option (or switch) in BOOT.INI

As Theo mentioned, it is used along with the compiler, it doesn't have

anything to do with W2K3.

More info can be found

http://blogs.msdn.com/oldnewthing/archive/2004/08/12/213468.aspx

http://www.eggheadcafe.com/community/aspnet/2/81127/largeaddressaware-issue.aspx

and elsewhere on the web by googling "LARGEADDRESSWARE switch compiler"

Carlos

"InputIO" wrote:

> Hi Theo,

>

> thanks for your reply !

>

> I try to read some KB Articles but not understand how to enable the

> "LARGEADDRESSAWARE" option.

>

> The question is : i need edit a boot.ini file and add /LARGEADDRESSAWARE

> after the sting multi(0)disk(0)rdisk(0).... ?!!?!?!

>

> Thanks in advance.

>

> "Theo" <theo@discussions.microsoft.com> ha scritto nel messaggio

> news:Ob3rmTiTIHA.4272@TK2MSFTNGP06.phx.gbl...

> > Unless I am mis-interpreting something, your information is not entirely

> > correct.

> >

> > If you go to http://www.microsft.com and enter 'LARGEADDRESSAWARE' in the search

> > box you will be given links to information indicating this is a

> > programming option for the linker at compile time.

> >

> > InputIO wrote:

> >> Hy guys!

> >>

> >> i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

> >> installed and have read that exist a option called "/LARGEADDRESSAWARE"

> >> that can use for improve the memory allocation for my application.

> >>

> >> The question is : how i can enable this option ? In boot.ini as the /3G

> >> on x86?

> >>

> >> Thanks in advance.

> >>

>

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

InputIO wrote:

> Hy guys!

>

> i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

> installed and have read that exist a option called "/LARGEADDRESSAWARE"

> that can use for improve the memory allocation for my application.

First: it is only used with 32-bit programs.

editbin is one tool that can set the flag. It comes with visual studio.

> The question is : how i can enable this option ? In boot.ini as the /3G

> on x86?

That option is for 32-bit Windows only. In 64-bit the application

automatically gets 4GB of virtual address space when the

LARGEADDRESSAWARE flag is set in the image header

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

"LARGEMEMORYADDRESSAWARE" is a flag used by the developer compiling a 32-bit

application to enable it to see >2GB of memory. The operating system needs

to make that memory available to the 32-bit application if it asks for it.

With Windows x64 Edition, you don't need to do ANYTHING to allow that 32-bit

application to see >2GB of memory. It happens automatically, and every

32-bit application automatically has a full 4GB of memory address space

available to it. If you're running a 32-bit application, you need to add a

/3GB switch to your boot up string in boot.ini to allow 32-bit applications

to see 3GB of virtual memory address space. That switch is unnecessary in

x64 Windows.

As an end user or administrator, there is nothing you need to do, or can do,

about LARGEMEMORYADDRESSAWARE. That is purely a developer flag.

--

Charlie.

http://msmvps.com/xperts64

http://mvp.support.microsoft.com/profile/charlie.russel

"InputIO" <InputIO@xxx.com> wrote in message

news:eps0ANiTIHA.6036@TK2MSFTNGP03.phx.gbl...

> Hy guys!

>

> i have a server with windows server 2003 ent. x64 Sp2 with 4Gbyte RAM

> installed and have read that exist a option called "/LARGEADDRESSAWARE"

> that can use for improve the memory allocation for my application.

>

> The question is : how i can enable this option ? In boot.ini as the /3G

> on x86?

>

> Thanks in advance.

>

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Charlie Russel - MVP wrote:

> With Windows x64 Edition, you don't need to do ANYTHING

> to allow that 32-bit application to see >2GB of memory. It happens

> automatically, and every 32-bit application automatically has a full 4GB

> of memory address space available to it.

Just to clear that up. I say something else in my post.

http://support.microsoft.com/kb/888732

Unless the flag in set, the application only gets 2GB in both 32-bit and

64-bit Windows

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

No, the Application GETS 4 GB in x64. It it can't USE or SEE the 4GB unless

the application is compiled accordingly. But the memory address space is

allocated regardless. This is _different_ from 32-bit Windows, where the

application only GETS 2GB unless you boot with the /3GB switch.

--

Charlie.

http://msmvps.com/xperts64

http://mvp.support.microsoft.com/profile/charlie.russel

"jorgen" <na@invalid> wrote in message

news:en2gCIjTIHA.2000@TK2MSFTNGP05.phx.gbl...

> Charlie Russel - MVP wrote:

>> With Windows x64 Edition, you don't need to do ANYTHING to allow that

>> 32-bit application to see >2GB of memory. It happens automatically, and

>> every 32-bit application automatically has a full 4GB of memory address

>> space available to it.

>

> Just to clear that up. I say something else in my post.

>

> http://support.microsoft.com/kb/888732

>

> Unless the flag in set, the application only gets 2GB in both 32-bit and

> 64-bit Windows

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Charlie Russel - MVP wrote:

> No, the Application GETS 4 GB in x64. It it can't USE or SEE the 4GB

> unless the application is compiled accordingly. But the memory address

> space is allocated regardless. This is _different_ from 32-bit Windows,

> where the application only GETS 2GB unless you boot with the /3GB switch.

That can very easily be misunderstood. I wouldn't use the word GET, when

it is not available to the application.

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

jorgen wrote:

:: Charlie Russel - MVP wrote:

::: No, the Application GETS 4 GB in x64. It it can't USE or SEE the

::: 4GB unless the application is compiled accordingly. But the

::: memory address space is allocated regardless. This is _different_

::: from 32-bit Windows, where the application only GETS 2GB unless

::: you boot with the /3GB switch.

::

:: That can very easily be misunderstood. I wouldn't use the word

:: GET, when it is not available to the application.

But it IS available, it is up to the application to be able to use it.

Bo Persson

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

jorgen wrote:

> Charlie Russel - MVP wrote:

>> No, the Application GETS 4 GB in x64. It it can't USE or SEE the 4GB

>> unless the application is compiled accordingly. But the memory address

>> space is allocated regardless. This is _different_ from 32-bit

>> Windows, where the application only GETS 2GB unless you boot with the

>> /3GB switch.

>

> That can very easily be misunderstood. I wouldn't use the word GET, when

> it is not available to the application.

"and every 32-bit application automatically has a full 4GB of memory

address space available to it. "

maybe i just misunderstood that part. I thought you claimed that all

applications would get 4GB with or without the LARGEADDRESSAWARE flag

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Bo Persson wrote:

> But it IS available, it is up to the application to be able to use it.

Yes, if the LARGEADDRESSAWARE flag is set

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

clearly you did.

The problem is that we're talking about two different things here. And

neither of them is RAM.

One is the ability of a 32-bit application to use >2GB of memory address

space. Unless it is compiled with the LARGEMEMORYADDRESSAWARE flag, it

simply can't. Full stop.

The second is the availability of memory address space to an application

from the OS. In 32-bit Windows, there is a TOTAL of 4GB of flat virtual

memory address space. That is normally divided 2GB for the OS, and 2GB for

applications. In x64 Windows, there is a total of 16 TB of flat virtual

memory address space. (yes, I said TB!) That is divided 8 TB for the OS, and

8 TB for applications.

If an application is compiled using the LARGEMEMORYADDRESSAWARE flag, then

it can see >2GB of virtual memory address space IFF (if and only if) the OS

makes that memory address space available to the application. With _some_

versions of 32-bit Windows, that is possible using the /3GB switch. There's

a price for using that switch - you've now starved the OS itself from having

enough virtual memory address space to function optimally, since it only has

4 GB of virtual memory address space in total available. With 64-bit

Windows, each 32-bit application gets it's own 4 GB of virtual memory

address space (via WOW64).

Just so you're aware, several of the whitepapers up on microsoft.com on x64

Windows are ones that I wrote for them.

--

Charlie.

http://msmvps.com/xperts64

http://mvp.support.microsoft.com/profile/charlie.russel

"jorgen" <na@invalid> wrote in message

news:essZhfjTIHA.1208@TK2MSFTNGP03.phx.gbl...

> jorgen wrote:

>> Charlie Russel - MVP wrote:

>>> No, the Application GETS 4 GB in x64. It it can't USE or SEE the 4GB

>>> unless the application is compiled accordingly. But the memory address

>>> space is allocated regardless. This is _different_ from 32-bit Windows,

>>> where the application only GETS 2GB unless you boot with the /3GB

>>> switch.

>>

>> That can very easily be misunderstood. I wouldn't use the word GET, when

>> it is not available to the application.

>

> "and every 32-bit application automatically has a full 4GB of memory

> address space available to it. "

>

> maybe i just misunderstood that part. I thought you claimed that all

> applications would get 4GB with or without the LARGEADDRESSAWARE flag

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

jorgen wrote:

:: Bo Persson wrote:

::

::: But it IS available, it is up to the application to be able to

::: use it.

::

:: Yes, if the LARGEADDRESSAWARE flag is set

That is a statement of conformance, the program must also be ABLE to

use the extra space.

http://blogs.msdn.com/oldnewthing/archive/2004/08/12/213468.aspx

Bo Persson

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Charlie Russel - MVP wrote:

> clearly you did.

>

> The problem is that we're talking about two different things here. And

> neither of them is RAM.

We are actually talking about the same thing. And I do differentiate

between RAM, physical address space, virtual address space, between user

space and kernel space etc.

I just thought you said, that every 32-bit application automatically was

able to grow to 4GB in 64-bit Windows - even without the flag in the

image header. Nothing more than that :)

January 3, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Bo Persson wrote:

> That is a statement of conformance, the program must also be ABLE to

> use the extra space.

>

> http://blogs.msdn.com/oldnewthing/archive/2004/08/12/213468.aspx

Yes, I'm aware of that. But if the flag is NOT set, the application

won't be able to grow beyond 2GB. That was the confusion in the thread :)

January 4, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Sorry but i still to don't understand.... :-(

1 case : 32 bit application on windows server x64

in this case it's mandatory compile my application with the flag

/LARGEADDRESSAWAR for see >2 Gb of memory or not ?

2 case: 64 bit aplication on windows server x64

in this case i need make anything on my server or my application for use

more than 2GB ?

3 case : 23 bit application on window server 32 bit

in this case after set the /3GB flag in boot.ini i nedd make anything on my

server or application for use more than 2GB ?

Thanks in advance.

bye :)

"jorgen" <na@invalid> ha scritto nel messaggio

news:ee$4$1jTIHA.4696@TK2MSFTNGP05.phx.gbl...

> Charlie Russel - MVP wrote:

>> clearly you did.

>>

>> The problem is that we're talking about two different things here. And

>> neither of them is RAM.

>

> We are actually talking about the same thing. And I do differentiate

> between RAM, physical address space, virtual address space, between user

> space and kernel space etc.

>

> I just thought you said, that every 32-bit application automatically was

> able to grow to 4GB in 64-bit Windows - even without the flag in the image

> header. Nothing more than that :)

January 4, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

InputIO wrote:

:: Sorry but i still to don't understand.... :-(

::

:: 1 case : 32 bit application on windows server x64

::

:: in this case it's mandatory compile my application with the flag

:: /LARGEADDRESSAWAR for see >2 Gb of memory or not ?

Yes.

::

:: 2 case: 64 bit aplication on windows server x64

::

:: in this case i need make anything on my server or my application

:: for use more than 2GB ?

No.

::

:: 3 case : 23 bit application on window server 32 bit

::

:: in this case after set the /3GB flag in boot.ini i nedd make

:: anything on my server or application for use more than 2GB ?

You still need the /LARGEADDRESSAWARE flag, for the application to

even attempt to use > 2GB.

Bo Persson

January 4, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

There's a bit of confusion in this thread, although the technical details

came out fine in the end.

To sum up:

- 32-bit applications can opt-in to use >2 GB of virtual address space by

using /LARGEADDRESSAWARE when they are built by the developer. There are

some compataiblity implications that the developer must handle correctly to

support this, which is why by default 32-bit applications never get more

than 2 GB in the first place. Just forcing this on by using editbin could

easily result in corruptions, crashes, or other major failures.

- Such applications will only actually be able to allocate >2 GB if the OS

they are running on is also configured to support this. For 32-bit versions

of Windows, this requires special boot modes and even then can never get

more than a total of 3 GB. For 64-bit versions of Windows, there is NO

special boot mode required and can grow to a full 4 GB. Standard 32-bit

applications (i.e., those without /LARGEADDRESSAWARE) will still never get

>2 GB no matter how the OS is configured.

- 64-bit applications always have access to at least 8 TB of virtual address

space.

How much physical RAM an application uses is a slightly different matter,

but as an approximiation you need as much Virtual Address Space as you have

physical memory allocated at a given time plus some more for other things

like memory-mapped files, Direct3D devices, EXE and DLL size, etc.

There's a nice summary of this in the DirectX SDK article "64-bit

programming for Game Developers"

http://msdn2.microsoft.com/en-us/library/bb147385.aspx ,as well information

in many of the whitepapers Charlie pointed to on MSDN's websites.

--

Chuck Walbourn

SDE, XNA Developer Connection

This posting is provided "AS IS" with no warranties, and confers no rights.

January 4, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

Bo is correct on all three points.

--

Charlie.

http://msmvps.com/xperts64

http://mvp.support.microsoft.com/profile/charlie.russel

"InputIO" <InputIO@xxx.com> wrote in message

news:eUM8CNuTIHA.4272@TK2MSFTNGP06.phx.gbl...

> Sorry but i still to don't understand.... :-(

>

> 1 case : 32 bit application on windows server x64

>

> in this case it's mandatory compile my application with the flag

> /LARGEADDRESSAWAR for see >2 Gb of memory or not ?

>

> 2 case: 64 bit aplication on windows server x64

>

> in this case i need make anything on my server or my application for use

> more than 2GB ?

>

> 3 case : 23 bit application on window server 32 bit

>

> in this case after set the /3GB flag in boot.ini i nedd make anything on

> my server or application for use more than 2GB ?

>

> Thanks in advance.

>

> bye :)

>

> "jorgen" <na@invalid> ha scritto nel messaggio

> news:ee$4$1jTIHA.4696@TK2MSFTNGP05.phx.gbl...

>> Charlie Russel - MVP wrote:

>>> clearly you did.

>>>

>>> The problem is that we're talking about two different things here. And

>>> neither of them is RAM.

>>

>> We are actually talking about the same thing. And I do differentiate

>> between RAM, physical address space, virtual address space, between user

>> space and kernel space etc.

>>

>> I just thought you said, that every 32-bit application automatically was

>> able to grow to 4GB in 64-bit Windows - even without the flag in the

>> image header. Nothing more than that :)

>

January 4, 2008

Re: About "LARGEADDRESSAWARE" option in W2K3 SP2 x64

correct. ;)

--

Charlie.

http://msmvps.com/xperts64

http://mvp.support.microsoft.com/profile/charlie.russel

"Chuck Walbourn [MSFT]" <chuckw@online.microsoft.com> wrote in message

news:OnDDZ4wTIHA.1168@TK2MSFTNGP02.phx.gbl...

> There's a bit of confusion in this thread, although the technical details

> came out fine in the end.

>

> To sum up:

>

> - 32-bit applications can opt-in to use >2 GB of virtual address space by

> using /LARGEADDRESSAWARE when they are built by the developer. There are

> some compataiblity implications that the developer must handle correctly

> to support this, which is why by default 32-bit applications never get

> more than 2 GB in the first place. Just forcing this on by using editbin

> could easily result in corruptions, crashes, or other major failures.

>

> - Such applications will only actually be able to allocate >2 GB if the OS

> they are running on is also configured to support this. For 32-bit

> versions of Windows, this requires special boot modes and even then can

> never get more than a total of 3 GB. For 64-bit versions of Windows, there

> is NO special boot mode required and can grow to a full 4 GB. Standard

> 32-bit applications (i.e., those without /LARGEADDRESSAWARE) will still

> never get

> >2 GB no matter how the OS is configured.

>

> - 64-bit applications always have access to at least 8 TB of virtual

> address space.

>

> How much physical RAM an application uses is a slightly different matter,

> but as an approximiation you need as much Virtual Address Space as you

> have physical memory allocated at a given time plus some more for other

> things like memory-mapped files, Direct3D devices, EXE and DLL size, etc.

>

> There's a nice summary of this in the DirectX SDK article "64-bit

> programming for Game Developers"

> http://msdn2.microsoft.com/en-us/library/bb147385.aspx ,as well

> information in many of the whitepapers Charlie pointed to on MSDN's

> websites.

>

> --

> Chuck Walbourn

> SDE, XNA Developer Connection

>

> This posting is provided "AS IS" with no warranties, and confers no

> rights.

>

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