From: Gregg N 

Rich wrote:
>    There is a different between soft faults and hard faults.  A soft
> fault is what a page is not in the working set of the process and while
> a page fault occurs the action to resolve the fault is to find the
> already loaded page in memory and to add it to the process working set.
> Soft faults are relatively cheap.  Another form of fault you might be
> seeing are with demand zero pages.  This is a page you have allocated
> but not yet touched.  One first reference a physical page is allocated
> and zero filled.  Finally, one form of hard fault you could be taking is
> with a non-private page such as a page (code or data) from an executable
> or a mapped file page that is not modified so gets loaded from and
> reloaded from the executable or mapped file.  I haven't looked so this
> may not help but it may be that perfmon distinguishes between the
> variations of page fault and you can see which is which.

Thanks for the explanation. I've always understood "working set"
to be a theoretical notion having more to do with caching than with paging.
For Windows, is this an actual table of some sort? What would cause a page
to be in memory but not in this table?

Gregg

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