FltXXX functions vs. ZwXXX functions (Filter Manager Beta)

NTFSD
2

Nir,

Unless you have a good reason not to, you should use the FltXxx APIs. They are more efficient then calling the Zw API (which trap back into the kernel) and we want to limit recursive IO to the top of the stack to only those cases that are necessary.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no rights

From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Nir Livni
Sent: Wednesday, January 26, 2005 1:31 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] FltXXX functions vs. ZwXXX functions (Filter Manager Beta)

Hi,
When using the Filter Manager framework ,
Is there a reason for me to prefer the FltXXX functions over the ZwXXX functions ?
What is the difference , for example, between FltCreateFile and ZwCreateFile, other than the ability to control which other filters will filter this IRP ?
?
Thanks,
Nir

Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Neal Christiansen wrote:

Nir,

Unless you have a good reason not to, you should use the FltXxx APIs. They are more efficient then calling the Zw API (which trap back into the kernel) and we want to limit recursive IO to the top of the stack to only those cases that are necessary.

Is the information about the Fltxxx APIs published anywhere? I applied
to the IFS beta but was presumably rejected (as I didn’t get a reply)
don’t have any information about them.

Are they also in Win2000? What about NT4? I have a requirement for
backward compatibility with both (which is easily achievable with the
current filter API).

Tony

4

Tony,

Presently these APIs are only documented as part of the Beta IFSKit.
When Srv03 SP1 is released in a few months a new IFSKit will be released
which will contain all of the documentations.

You should have received a response for registering for the IFSKit beta.
You should get a response back within a few days. The only prerequisite
is that you have purchased an IFSKit. Please send an email to
xxxxx@microsoft.com to find out what is going on.

The filter manager will be supported on W2K. It will be released Q2,
2005 with the Windows 2000 SP4 SRP (security rollup). A pre-beta for
this is starting this week.

For info on the SRP go to:
http://www.microsoft.com/windows2000/server/evaluation/news/bulletins/ro
llup.asp

To register for the SRP beta go to: http://beta.microsoft.com
GuestID: Win2kURPTest

There will be no filter manager support for NT4.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Tony Hoyle
Sent: Friday, January 28, 2005 9:27 AM
To: Windows File Systems Devs Interest List
Subject: Re: [ntfsd] FltXXX functions vs. ZwXXX functions (Filter
Manager Beta)

Neal Christiansen wrote:

Nir,

Unless you have a good reason not to, you should use the FltXxx APIs.
They are more efficient then calling the Zw API (which trap back into
the kernel) and we want to limit recursive IO to the top of the stack to
only those cases that are necessary.

Is the information about the Fltxxx APIs published anywhere? I applied
to the IFS beta but was presumably rejected (as I didn’t get a reply)
don’t have any information about them.

Are they also in Win2000? What about NT4? I have a requirement for
backward compatibility with both (which is easily achievable with the
current filter API).

Tony

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com