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Date: Mon, 9 Feb 2009 18:44:42 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: dd in cygwin vs dd in linux - number of records is always 	different
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On Feb  9 17:27, Chris January wrote:
> On Mon, Feb 9, 2009 at 5:18 PM, Corinna Vinschen wrote:
> > I guess I'll ask on one of the Microsoft newsgroups if this is a known
> > effect and especially what I'm doing wrong or what I have to do to
> > get the desired behaviour.
> >
> > Btw., if anybody has an idea what's going wrong, please speak up :}
> 
> Maybe this excerpt from the CreateFile documentation applies?
> "Note  To read or write to the last few sectors of the volume, you
> must call DeviceIoControl and specify FSCTL_ALLOW_EXTENDED_DASD_IO.
> This signals the file system driver not to perform any I/O boundary
> checks on partition read or write calls. Instead, boundary checks are
> performed by the device driver."

You saved my day!  I never noticed that snippet in the docs.  Thank you
*SO* much.  I'll check in a patch to Cygwin which will use that on disk
devices.


Thanks again,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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