4GB in WOW

[onequestionone@yahoo.com]

Dear All,

My question is, can I allocate 4GB of physical memory when I run my
32bit application in Windows 64bit edition in a machine that has 16GB
memory. I already tried allocating of 3GB by configuring 32bit windows
but I need more. I think it may be possible because in 64bit I don't
have 1GB OS preallocated and WIN64 is running from somewhere else.
My program is a in memory database and need not to use virtual memory
and all its data should be in physical RAM.

Thanks for any reply,
John

 

[jacky kwok]

Re: 4GB in WOW

onequestionone@yahoo.com wrote:
> Dear All,
>
> My question is, can I allocate 4GB of physical memory when I run my
> 32bit application in Windows 64bit edition in a machine that has 16GB
> memory. I already tried allocating of 3GB by configuring 32bit windows
> but I need more. I think it may be possible because in 64bit I don't
> have 1GB OS preallocated and WIN64 is running from somewhere else.
> My program is a in memory database and need not to use virtual memory
> and all its data should be in physical RAM.
>
> Thanks for any reply,
> John
>


refer "http://msdn2.microsoft.com/en-us/isv/Bb190528.aspx"


In theory, 32 bit application can used near 4G virtual address space in
some condition.



--
Jacky Kwok
jacky@alumni_DOT_cuhk_DOT_edu_DOT_hk

 

[Charlie Russel - MVP]

Re: 4GB in WOW

You don't allocate memory - the OS does. That being said, yes, your 32-bit
application will have a full 4GB of memory address space, IF it was written
to be large memory aware. (If it can use the /3GB switch on 32-bit windows,
then yes, it can.)

How that 4GB of memory address space is actually assigned to physical RAM is
in the control of the OS. But with 16GB in the machine, you should be just
fine.

--
Charlie.
http://msmvps.com/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel


<onequestionone@yahoo.com> wrote in message
news:1185926316.271087.149290@m37g2000prh.googlegroups.com...
> Dear All,
>
> My question is, can I allocate 4GB of physical memory when I run my
> 32bit application in Windows 64bit edition in a machine that has 16GB
> memory. I already tried allocating of 3GB by configuring 32bit windows
> but I need more. I think it may be possible because in 64bit I don't
> have 1GB OS preallocated and WIN64 is running from somewhere else.
> My program is a in memory database and need not to use virtual memory
> and all its data should be in physical RAM.
>
> Thanks for any reply,
> John
>

 

[onequestionone@yahoo.com]

Re: 4GB in WOW

On Jul 31, 4:58 pm, onequestion...@yahoo.com wrote:
> Dear All,
>
> My question is, can I allocate 4GB of physical memory when I run my
> 32bit application in Windows 64bit edition in a machine that has 16GB
> memory. I already tried allocating of 3GB by configuring 32bit windows
> but I need more. I think it may be possible because in 64bit I don't
> have 1GB OS preallocated and WIN64 is running from somewhere else.
> My program is a in memory database and need not to use virtual memory
> and all its data should be in physical RAM.
>
> Thanks for any reply,
> John

Thanks for your replies. My program is an in-memory database and
somehow it is able to block physical RAM not virtual memory that OS
swap between HDD and RAM. At startup it blocks memory and other
programs can not access to that portion. My question is, what is the
behavior of WIN64? Can it allocate 4GB of physical memory for each
instance of 32bit application running in 64bit machine with WIN64?

John

 

[Charlie Russel - MVP]

Re: 4GB in WOW

Again, it doesn't "block physical memory". It may (and most likely does)
request an allocation of memory which it tells the OS can't be swapped. That
is not the same thing. It can not directly access physical RAM - that is and
MUST BE the job of the operating system.

If you're writing this program, use the LARGEMEMORYAWARE switch to compile
it. If this is done, then it will use 4GB in WOW64.

There is a great deal of confusion out there about RAM, virtual memory,
virtual memory address space, and swapping.

--
Charlie.
http://msmvps.com/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel


<onequestionone@yahoo.com> wrote in message
news:1185982589.252433.32500@j4g2000prf.googlegroups.com...
> On Jul 31, 4:58 pm, onequestion...@yahoo.com wrote:
>> Dear All,
>>
>> My question is, can I allocate 4GB of physical memory when I run my
>> 32bit application in Windows 64bit edition in a machine that has 16GB
>> memory. I already tried allocating of 3GB by configuring 32bit windows
>> but I need more. I think it may be possible because in 64bit I don't
>> have 1GB OS preallocated and WIN64 is running from somewhere else.
>> My program is a in memory database and need not to use virtual memory
>> and all its data should be in physical RAM.
>>
>> Thanks for any reply,
>> John
>
> Thanks for your replies. My program is an in-memory database and
> somehow it is able to block physical RAM not virtual memory that OS
> swap between HDD and RAM. At startup it blocks memory and other
> programs can not access to that portion. My question is, what is the
> behavior of WIN64? Can it allocate 4GB of physical memory for each
> instance of 32bit application running in 64bit machine with WIN64?
>
> John
>

 

[Homer J. Simpson]

Re: 4GB in WOW

Personally, if this in-memory database fits within 4GB, and I had a machine
with 16GB, I'd experiment with converting it back into a regular database,
only, copying the database file to a ramdisk at startup. However I've yet
to come across a 64-bit ramdisk driver.

Stupid, or not?

 

[Charlie Russel - MVP]

Re: 4GB in WOW

I'd experiment with converting it to a 64bit database app and have 16 GB to
play with.

More to the point, you'd have 8 TB of virtual memory address space to work
with.

--
Charlie.
http://msmvps.com/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel


"Homer J. Simpson" <root@127.0.0.1> wrote in message
news:OkrUfaQ1HHA.5980@TK2MSFTNGP04.phx.gbl...
> Personally, if this in-memory database fits within 4GB, and I had a
> machine with 16GB, I'd experiment with converting it back into a regular
> database, only, copying the database file to a ramdisk at startup.
> However I've yet to come across a 64-bit ramdisk driver.
>
> Stupid, or not?
>