What are FastIoRead,FastIowrite functions?

NTFSD
1

Hi to all

What are FastIoRead,FastIowrite functions?

What is the purpose of them?

Can we use it in Kernel mode programs?

Thanking u

2

Fast I/O requests are sent by the I/O Manager to optimize performance since
it is more efficient to send a Fast I/O request than to prepare an IRP and
then dispatch it.
How exactly do you want to use Fast I/O in your driver?

Regards,
Ayush Gupta
http://www.linkedin.com/in/guptaayush

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:bounce-370825-
xxxxx@lists.osr.com] On Behalf Of xxxxx@gmail.com
Sent: Tuesday, June 23, 2009 9:56 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] What are FastIoRead,FastIowrite functions?

Hi to all

What are FastIoRead,FastIowrite functions?

What is the purpose of them?

Can we use it in Kernel mode programs?

Thanking u

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars
(including our new fs mini-filter seminar) visit:
http://www.osr.com/seminars

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3

You are saying that…

that methods allows the I/O system to bypass generating an IRP and instead go directly to the file system driver or cache manager to complete an I/O request.

Whether this technique is used in Windows XP & vista Operating systems?

Will it increase the performance?

only file system drivers have any use for fast I/O routines.?

with regards

4

Yes the I/O manager attempts a Fast I/O first. If you disallow a fast i/o
then it builds an IRP and sends it.
Yes… it is helpful in improving system performance.
It is present in all Windows OS and is not specific to Vista or XP.

Regards,
Ayush

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:bounce-370875-
xxxxx@lists.osr.com] On Behalf Of xxxxx@gmail.com
Sent: Tuesday, June 23, 2009 8:04 PM
To: Windows File Systems Devs Interest List
Subject: RE:[ntfsd] What are FastIoRead,FastIowrite functions?

You are saying that…

that methods allows the I/O system to bypass generating an IRP and
instead go directly to the file system driver or cache manager to
complete an I/O request.

Whether this technique is used in Windows XP & vista Operating systems?

Will it increase the performance?

only file system drivers have any use for fast I/O routines.?

with regards

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars
(including our new fs mini-filter seminar) visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer