Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm 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 X-Injected-Via-Gmane: http://gmane.org/ To: cygwin@cygwin.com From: Rolf Campbell Subject: Re: SPARSE files considered harmful - please revert Date: Tue, 20 May 2003 11:01:08 -0400 Lines: 30 Message-ID: References: <16072.6666.10124.338022@gargle.gargle.HOWL> <00f301c31e12$c29efdb0$6400a8c0@FoxtrotTech0001> <00be01c31e15$944d0d50$78d96f83@pomello> <005601c31e26$77671260$6400a8c0@FoxtrotTech0001> <20030519175913.GA24066@redhat.com> <008001c31e5e$39c0c680$6400a8c0@FoxtrotTech0001> <20030520024151.GA1812@redhat.com> Reply-To: IDontLikePersonalReplies@hotmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@main.gmane.org User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4b) Gecko/20030507 X-Accept-Language: en-us, en In-Reply-To: <20030520024151.GA1812@redhat.com> Christopher Faylor wrote: > On Mon, May 19, 2003 at 07:27:06PM -0400, Bill C. Riemers wrote: > >>>I think you need to read the documentation a little more closely. Either that >>>or provide references to the parts of the documentation that says that >>>normal RW operations would fragment a sparse file. >> >>It is rather obvious. Let say you have three blocks worth of data, and >>is written into a file with a physical block followed by a sparse block >>followed by a physical block. No disk space is reserved for the sparse >>block. Why should it be, as it would defeat the whole purpose of using >>sparse files? So physically on disk you have two consecutive physical >>blocks. What then happens if you open the file in RW mode, seek to the >>sparse block and write some data? > > > 1) You are assuming behavior that isn't documented. I can imagine that > the first block could occupy, say 16 blocks and depending on the size of > the hole, there could be no fragmentation. A agree that he is making an assumption, but he is probably right. Even if 16 blocks are reserved for adding intermediate blocks, you would still end up with out-of-order blocks in the file; which isn't as bad as real fragmentation, but isn't as good as all blocks in order. > 3) What no one seems to be mentioning is that we are trying to emulate > UNIX behavior here. If the above is an issue for Windows then it could > also be an issue for UNIX. > cgf And it is. -- 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/