Dear Ken,
Thanks for the explanation.
Paul Cheuk
Tel: (852) 2987 7232
Fax: (852) 2987 3542, (852) 2987 4843
|---------+---------------------------->
| | Ken Schaefer |
| | <[EMAIL PROTECTED]|
| | .com> |
| | |
| | 14/05/08 09:36 |
| | Please respond to|
| | "NT System Admin |
| | Issues" |
| | |
|---------+---------------------------->
>------------------------------------------------------------------------------------------------------------------------------|
|
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| To: "NT System Admin Issues"
<[email protected]>
|
| cc:
|
| Subject: RE: Why XP is doomed
|
>------------------------------------------------------------------------------------------------------------------------------|
Will this affect performance?
If you are asking this type of question, then I suspect that you are
probably not very familiar with the memory management architecture of
Windows, so this isn't really something you should be doing. Michael has
provided steps on how to configure this if you want to.
In Windows, only the kernel sees physical memory
All user mode applications (most of those processes you see listed in Task
Manager) see "virtual memory" that's presented to them by the kernel. On a
32bit version of Windows, each application sees 4GB of address space.
Each application sees its own *unique* 4GB of address space - the
application believes that there is nothing else running on the system. Out
of that 4GB of address space, the upper 2GB is reserved for the kernel, and
the application itself is free to use the lower 2GB. Because each process
has the same layout for reserved kernel space, this is actually shared
between all processes.
OK - so now the virtual memory manager needs to map all this memory to real
physical memory. E.g. iexplore.exe uses bytes 0x00000001 -> 0x0000000F to
store an image. The Windows VMM needs to store this somewhere in physical
memory. It does so by using mapping tables.
Now, what happens when you only have 1GB of physical RAM in your machine,
but each application, thnking it has up to 2GB available, starts actually
*using* all that virtual memory? The VMM runs out of physical memory to
store all this stuff. So it moves some stuff to the page file. If you have
no page file, nothing can be moved, and your applications will start
crashing with out-of-memory exceptions (because the VMM will deny them
memory allocations).
If you system has plenty of physical RAM, then is no need for page file. If
your machine doesn't, you need a page file to "fake" physical RAM.
Cheers
Ken
> -----Original Message-----
> From: paul cheuk [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, 14 May 2008 11:16 AM
> To: NT System Admin Issues
> Subject: RE: Why XP is doomed
>
> Dear Ken,
>
> How can I configure Windows to run without a page file? Will this
> affect the performance ?
>
> Thanks.
>
>
> Paul Cheuk.
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