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From: Rdavies on 4 Mar 2010 06:05
Hi All,
Wonder if anybody can help me out...
I am trying to make use of AWE on Vista 32bit to allow access to
memory over the 4GByte boundary.
The problem is that my I don't seem to be able to find a way to make
the AWE extension to access the memory above 4GB.
My system is a Dell Dimension 9200 with 6Gbytes of memory.
If I do a system properties Vista is telling me that 6Gbytes is
actually installed.
However, GlobalMemoryStatusEx is not seeing more than 4Gbytes, and
stranger still ulAvailaExtenedVirtual is always returning zero? (This
is using the example from the GlobalMemoryStatusEx MSDN page).
Also the max amount of memory I can use allocate using
AllocateUserPhysicalPages (AWE function) is aprox 1.8Gbytes?

I have /pae enabled on boot and the processor installed supports PAE,
confirmed using IsProcessorFeaturePresent(PF_PAE_ENABLED).

So I do get GlobalMemoryStatusEx to return the correct size?
Also is there a way to control AWE to only allocate memory above the
4GB limit (assuming I can get the code to see above the 4Gb limit).

Thanks in advance

- Richard
From: Rdavies on 4 Mar 2010 09:26
On Mar 4, 11:05 am, Rdavies <rdavies_2...(a)yahoo.com> wrote:
> Hi All,
> Wonder if anybody can help me out...
> I am trying to make use of AWE on Vista 32bit to allow access to
> memory over the 4GByte boundary.
> The problem is that my I don't seem to be able to find a way to make
> the AWE extension to access the memory above 4GB.
> My system is a Dell Dimension 9200 with 6Gbytes of memory.
> If I do a system properties Vista is telling me that 6Gbytes is
> actually installed.
> However, GlobalMemoryStatusEx is not seeing more than 4Gbytes, and
> stranger still ulAvailaExtenedVirtual is always returning zero? (This
> is using the example from the GlobalMemoryStatusEx MSDN page).
> Also the max amount of memory I can use allocate using
> AllocateUserPhysicalPages (AWE function) is aprox 1.8Gbytes?
>
> I have /pae enabled on boot and the processor installed supports PAE,
> confirmed using IsProcessorFeaturePresent(PF_PAE_ENABLED).
>
> So I do get GlobalMemoryStatusEx to return the correct size?
> Also is there a way to control AWE to only allocate memory above the
> 4GB limit (assuming I can get the code to see above the 4Gb limit).
>
> Thanks in advance
>
> - Richard

OK, so if I'd only looked the MSDN page more carefully then I would
have seen that ulAvailaExtenedVirtual is always set to 0....

But I still have the question on how to make AWE use memory above the
4GB limit.
From: David Schwartz on 7 Mar 2010 12:58
On Mar 4, 6:26 am, Rdavies <rdavies_2...(a)yahoo.com> wrote:

> But I still have the question on how to make AWE use memory above the
> 4GB limit.

You have 32-bit Windows. You need 64-bit Windows to access memory
above the 4GB limit. While AWE will allow a 32-bit process to access
more memory than can fit in its virtual address space, a process can
only access memory the operating system can access.

DS
From: Rdavies on 8 Mar 2010 13:19
On Mar 7, 5:58 pm, David Schwartz <dav...(a)webmaster.com> wrote:
> On Mar 4, 6:26 am, Rdavies <rdavies_2...(a)yahoo.com> wrote:
>
> > But I still have the question on how to make AWE use memory above the
> > 4GB limit.
>
> You have 32-bit Windows. You need 64-bit Windows to access memory
> above the 4GB limit. While AWE will allow a 32-bit process to access
> more memory than can fit in its virtual address space, a process can
> only access memory the operating system can access.
>
> DS

Hi DS,

I hear you... but from looking at the MSDN doc the whole point of PAE
+ AWE is to allow 32bit applications to get to greater than 4G of
memory.
"http://msdn.microsoft.com/en-us/library/aa366796(VS.85).aspx", take a
look at the last paragraph.... "AWE does not require PAE or 4GT but is
often used together with PAE to allocate more than 4 GB of physical
memory from a single 32-bit process."

Very strange, anybody else have any comments.

Richard
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