From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756251AbYIKVJT (ORCPT ); Thu, 11 Sep 2008 17:09:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753346AbYIKVJK (ORCPT ); Thu, 11 Sep 2008 17:09:10 -0400 Received: from caffeine.csclub.uwaterloo.ca ([129.97.134.17]:54313 "EHLO caffeine.csclub.uwaterloo.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753020AbYIKVJJ (ORCPT ); Thu, 11 Sep 2008 17:09:09 -0400 Date: Thu, 11 Sep 2008 17:09:08 -0400 To: "H. Peter Anvin" Cc: Harun Scheutzow , linux-kernel@vger.kernel.org Subject: Re: vfat file system extreme fragmentation on multiprocessor Message-ID: <20080911210908.GC31271@csclub.uwaterloo.ca> References: <0ML29c-1KdqyO1YV1-0001g5@mrelayeu.kundenserver.de> <20080911191049.GB31271@csclub.uwaterloo.ca> <48C97338.5080502@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48C97338.5080502@zytor.com> User-Agent: Mutt/1.5.13 (2006-08-11) From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 11, 2008 at 12:36:24PM -0700, H. Peter Anvin wrote: > Lennart Sorensen wrote: > > > >I don't think fat filesystems have any concept of reserving space for > >expanding files. It's a pretty simple filesystem after all designed for > >a single cpu machine with a non-multitasking OS (if you can call DOS an > >OS). Space tends to be allocated from the start of the disk wherever > >free space is found since otherwise you would have to go searching for > >the free space, which isn't that efficient. > > > > Well, you can always do that in-memory. It still involves searching no matter where you do it. With FAT-16 that means up to 2^16 clusters to search through. With FAT-32 even more. It doesn't have a cluster bitmap to speed things up. -- Len Sorensen