allocation granularity size boundary

NTFSD
1

In the docs for ZwMapViewOfSection it has the following description for the
parameter

SectionOffset

Pointer to the offset, in bytes, from the beginning of the section to the
view. If this pointer is non-NULL, the given value is rounded down to the
next allocation granularity size boundary.

How does one know what the next allocation granularity size boundary is?

It appears to be 64K, but is there a define or something to determine what
it is?

Thanks,

Ken

2

> How does one know what the next allocation granularity size boundary is?

It appears to be 64K, but is there a define or something to determine what it is?

It is 64 KB, for i386 platforms. See the GetSystemInfo Win32 API for
getting the allocation granularity.

L.

3

Thanks for the info, but how can I get this information in a kernel driver?
I will need this information for ia64 and amd64.

Ken

From: Ladislav Zezula [mailto:xxxxx@volny.cz]
Sent: Wednesday, January 26, 2005 3:58 AM
To: Windows File Systems Devs Interest List
Subject: Re: [ntfsd] allocation granularity size boundary

How does one know what the next allocation granularity size boundary is?

It appears to be 64K, but is there a define or something to determine what
it is?

It is 64 KB, for i386 platforms. See the GetSystemInfo Win32 API for

getting the allocation granularity.

L.

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

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4

> Thanks for the info, but how can I get this information in a kernel driver?

See here:

http://www.osronline.com/showThread.CFM?link=70007

L.

5

You Da Man! Thanks!

From: Ladislav Zezula [mailto:xxxxx@volny.cz]
Sent: Thursday, January 27, 2005 1:43 AM
To: Windows File Systems Devs Interest List
Subject: Re: [ntfsd] allocation granularity size boundary

Thanks for the info, but how can I get this information in a kernel
driver?

See here:

http://www.osronline.com/showThread.CFM?link=70007
http:

L.

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

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6

Hmm, unfortunately the function and structure are not documented. I don’t
mind using the function but undocumented structures are kind of scary.

Hey Microsoft, is there a sanctioned way to get this information?

Can this API be added for the future?

Thanks,

Ken

From: Ken Galipeau [mailto:xxxxx@emc.com]
Sent: Thursday, January 27, 2005 8:19 AM
To: Windows File Systems Devs Interest List
Subject: RE: [ntfsd] allocation granularity size boundary

You Da Man! Thanks!

From: Ladislav Zezula [mailto:xxxxx@volny.cz]
Sent: Thursday, January 27, 2005 1:43 AM
To: Windows File Systems Devs Interest List
Subject: Re: [ntfsd] allocation granularity size boundary

Thanks for the info, but how can I get this information in a kernel
driver?

See here:

http://www.osronline.com/showThread.CFM?link=70007
http:

L.

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

You are currently subscribed to ntfsd as: unknown lmsubst tag argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

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

You are currently subscribed to ntfsd as: unknown lmsubst tag argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com</http:>