Guest onequestionone@yahoo.com Posted July 31, 2007 Posted July 31, 2007 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
Guest jacky kwok Posted August 1, 2007 Posted August 1, 2007 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
Guest Charlie Russel - MVP Posted August 1, 2007 Posted August 1, 2007 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 >
Guest onequestionone@yahoo.com Posted August 1, 2007 Posted August 1, 2007 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
Guest Charlie Russel - MVP Posted August 1, 2007 Posted August 1, 2007 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 >
Guest Homer J. Simpson Posted August 2, 2007 Posted August 2, 2007 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?
Guest Charlie Russel - MVP Posted August 2, 2007 Posted August 2, 2007 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? >
Recommended Posts