X-Recipient: archive-cygwin AT delorie DOT com
X-Spam-Check-By: sourceware.org
X-Authority-Analysis: v=1.0 c=1 a=xe8BsctaAAAA:8 a=RjXWjYkkwJnsyY8aGOsA:9 a=neNzenzz71bmjqyXtoAuF2RZQ-cA:4 a=eDFNAWYWrCwA:10 a=rPt6xJ-oxjAA:10
Message-ID: <47508475.7000109@byu.net>
Date: Fri, 30 Nov 2007 14:45:25 -0700
From: Eric Blake <ebb9 AT byu DOT net>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071031 Thunderbird/2.0.0.9 Mnenhy/0.7.5.666
MIME-Version: 1.0
To: cygwin AT cygwin DOT com, steve AT kelker DOT net
Subject: Re: cp.exe chunk size
References: <14093712 DOT post AT talk DOT nabble DOT com>
In-Reply-To: <14093712.post@talk.nabble.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-IsSubscribed: yes
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

According to skelker on 11/30/2007 2:23 PM:
> Hi,
> Is there a reason that cp.exe uses 8KB chunk sizes to copy files?  This
> behavior leads to very fragmented files, especially when copying large
> files.

This has been brought up before, if you want to search the archives for
posix_fallocate.  The problem is not with cp.exe, but with the way that
the POSIX read/write functions are implemented on top of Windows system
calls in cygwin1.dll.  When cygwin 1.7.0 comes out, I will be
experimenting with using posix_fallocate to see if that can reduce the
fragmentation.  But in the meantime, you'll have to just live with it.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             ebb9 AT byu DOT net
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFHUIR184KuGfSFAYARAkVyAKDHRbMhsJhY+9CseozooXZygU8xewCghlGj
ujKefnP3WWUI4PTX5wGNCuo=
=AgaY
-----END PGP SIGNATURE-----

--
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/