Re: 32-bit programs on Windows x64

On Jul 3, 7:52 am, Tim Slattery <Slatter...@xxxxxxx> wrote:
"Peter Olcott" <NoS...@xxxxxxxxxxxxx> wrote:
Can two 32-bit programs each have access to 4.0 GB of RAM,
if there is 8.0 GB of RAM on the system?

On a 32-bit system, each process gets a 4GB virtual memory space. At
any time, bits of this space are in physical RAM, or on disk, or
noplace (since they haven't been allocated yet). The OS keeps track of
where everything is.

If you've got 8GB of RAM, then you must have a 64-bit system. I'm not
sure what the virtual memory space for each process is on a 64-bit
system, but I'm sure it's much larger than the 4GB, 32-bit limit.

Either way, the amount of physical RAM is *not* a limiting factor.
Since with more physical RAM you can have more bits of the VM spaces
in RAM, things will run faster. But things will continue to run even
with small amounts of physical RAM, just more slowly.

--
Tim Slattery
MS MVP(Shell/User)
Slatter...@xxxxxxxxxxx://members.cox.net/slatteryt

64-bit vs. 32-bit architecture
Address space 64-bit Windows 32-bit Windows
Virtual memory 16 terabytes 4 GB
Paging file 512 terabytes 16 terabytes
Paged pool 128 GB 470 MB
Non-paged pool 128 GB 256 MB
System cache 1 terabyte 1 GB

What I am trying to confirm is whether or not 32-bit applications are
limited to being placed in the lowest 4.0 GB of RAM, thus the total
available RAM available to all 32-bit applications could possibly be
constrained to 4.0 GB. Alternatively, each application could have its
virtual address space map to as much as 4.0 GB of actual RAM. I am
guessing that the latter is true.
.

Relevant Pages

  • Re: should I go for 64bit version of Fedora 11 ?
    ... |> Any software that can make use of more than 3 GB of virtual memory space ... |> will benefit from a 64 bit install. ... Leaving aside any x86 architecturable hobbling that may be cleaner in the ... of RAM or mmap>4GB of a file) 32-bit would use physically smaller ...
    (Fedora)
  • Re: Pagefile.sys
    ... What is meant by such wording is "set the system to use no page file space at all." ... The reason is that when programs ask for an allocation of Virtual memory space, they may ask for a great deal more than they ever actually bring into use - the total may easily run to hundreds of megabytes. ... If there is a page file available, the system can assign them to it - if there is not, they have to be assigned to RAM, locking it out from any actual use. ...
    (microsoft.public.windowsxp.basics)
  • Re: 32-bit programs on Windows x64
    ... if there is 8.0 GB of RAM on the system? ... each process gets a 4GB virtual memory space. ... the amount of physical RAM is *not* a limiting factor. ...
    (microsoft.public.vc.mfc)
  • Re: OS X on my G3
    ... given sufficient RAM and hard drive space. ... It isn't easy to upgrade the RAM as it requires opening up the machine ... which will leave you less for applications and data. ... or you can find another way to install the software via ...
    (comp.sys.mac.hardware.misc)
  • Re: where do you store app wide data?
    ... Not the JVM.. ... Java applications. ... thats the fault of whoever wrote the application - not Java. ... Files are not stored in RAM when you close them. ...
    (alt.php)
Loading