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Re: Error reported dd'ing close of end of block device with skip

On Dec 13 19:05, Loh, Joe wrote:
> We downloaded cygwin-inst-20051213.tar.bz2 and implemented the solution
> recommended below.  So far, our cursory testing indicates that we are
> able to do unbuffered read.  However, we are not seeing any "bug" that
> was referenced here.  What is the "bug" that is being referenced here?

The RDIOCDOP/RDSETBLK was incorrectly implemented when a request was
made to set the buffer size to 0 or 1 (aka "non-buffered").  But since
that's fixed in the above snapshot, you can't trip over it.

Btw., I just applied a patch which implements O_DIRECT, which will be
available in the next snapshot.  The same restriction as on Linux
applies, which is, the buffers used in read/write operations must be
sector-aligned.  Note that using O_DIRECT requires to rebuild the
application, so you'll be unable to experiment with this using the
current versions of dd(1).


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

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