Re: Memory Management in Win NT/2000

From: Jim Nugent (njim2k-nntp_at_yahoo.com)
Date: 02/05/05 

Date: Sat, 5 Feb 2005 12:55:50 -0600

"Abhishek" <abhi_narulkar@rediffmail.com> wrote in message
news:%23xDidlnCFHA.2960@TK2MSFTNGP14.phx.gbl...
> Hello,
> I would like to understand the fundamental of Virtual Memory
> Management in Windows 2000.
> My question is does the Windows 2000 starts using Virtual Memory right
from
> the word go..?
> For example lets say I have 200 MB of free physical memory, and I want to
> execute a program which requires
> a total of 10 MB of memory. Though what I know is that Windows NT/2000
> allocates 4 GB of address space
> to the process, but what I am not sure is whether out of 10 MB requirement
> of the process, how much of the
> actual physical memory is allocated to the process. Assuming there is no
> other user process running on the system and
> all the physical memory can be used. Now in this case whether Windows
> NT/2000 would keep only a portion of the
> 10 MB in physical memory and rest on disk(Virtual Memory) or whether it
> would put all the 10 MB in memory so that
> the process has minimum page faults and thus improve performance.
> I hope I was able to explain my doubt,

It will try to load the whole program. This is in contrast to, say, AT&T
Unix where it would create the necessary control structures, and then "fault
the pages in" as they are referenced. Since the code is "pure" it can use
the executable for this purpose and never has to write code to the page file
because it never gets "dirty." It can throw pages way and get them later
from the executable.

I don't know if Windows is this smart, or is willing to sacrifice the
performance. 

--
Jim
"Remember, an amateur built the Ark; professionals built the Titanic."

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