X-Spam-Check-By: sourceware.org Date: Wed, 14 Dec 2005 17:00:53 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: Error reported dd'ing close of end of block device with skip Message-ID: <20051214160053.GK2399@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2i Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com 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 -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat, Inc. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/