From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: ATA 4 KiB sector issues. Date: Mon, 08 Mar 2010 10:29:56 -0800 Message-ID: <4B954224.6010208@zytor.com> References: <4B947393.2050002@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from terminus.zytor.com ([198.137.202.10]:60493 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751969Ab0CHSdH (ORCPT ); Mon, 8 Mar 2010 13:33:07 -0500 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: "Martin K. Petersen" Cc: Tejun Heo , "linux-ide@vger.kernel.org" , lkml , Daniel Taylor , Jeff Garzik , Mark Lord , tytso@mit.edu, hirofumi@mail.parknet.co.jp, Andrew Morton , Alan Cox , irtiger@gmail.com, Matthew Wilcox , aschnell@suse.de, knikanth@suse.de, jdelvare@suse.de, Karel Zak , Jim Meyering On 03/08/2010 07:18 AM, Martin K. Petersen wrote: > > Tejun> Partitioners maybe should only align partitions which will be > Tejun> used by Linux and default to the traditional layout for others > Tejun> while allowing explicit override. > > I don't think we take the partition type into account. Karel? > We should not take the partition type into account. The other aspect is that FAT partitions need to be formatted differently to maintain the alignment once set; I have recently contributed patches (which were accepted) into mkdosfs to do the right thing there. Looking at the Windows XP article, it looks like it is limited to certain BIOSes; unfortunately it doesn't say what the particular BIOS issue is. If we can find a system which actually exhibits the bug it might be possible to reverse-engineer a solution. > Tejun> Reportedly, commonly used partitioners aren't ready to handle > Tejun> drives larger than 2 TiB in any configuration and alignment isn't > Tejun> done properly for drives with 4 KiB physical sectors. 4 KiB > Tejun> logical sector support is broken in both the kernel > > Huh, what? My homedir is on a 4KiB LBS/PBS drive and has been for ~2 > years. For > 2 TiB drives with 4 KiB logical sectors and MS-DOS partition tables, it is. > Tejun> Unfortunately, the transition to 4 KiB sector size, physical only > Tejun> or logical too, is looking fairly ugly. Hopefully, a reasonable > Tejun> solution can be reached in not too distant future but even with > Tejun> all the software side updated, it looks like it's gonna cause > Tejun> significant amount of confusion and frustration. > > With regards to XP compatibility I don't think we should go too much out > of our way to accommodate it. XP has been disowned by its master and I > think virtualization will take care of the rest. I think that's is wildly optimistic, but I do observe there is a fix from Microsoft in the article you reference. > FWIW, recent fdisk has a command line flag that will enable/disable DOS > compatible layout. Yes, unfortunately it is still on by default. -hpa