From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751612Ab0CQDBV (ORCPT ); Tue, 16 Mar 2010 23:01:21 -0400 Received: from ppp167-251-209.static.internode.on.net ([59.167.251.209]:60017 "EHLO cheesypoof.guarana.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079Ab0CQDBU (ORCPT ); Tue, 16 Mar 2010 23:01:20 -0400 X-Greylist: delayed 613 seconds by postgrey-1.27 at vger.kernel.org; Tue, 16 Mar 2010 23:01:19 EDT Date: Wed, 17 Mar 2010 13:51:01 +1100 From: Kevin Easton To: James Bottomley Cc: linux-kernel@vger.kernel.org, Tejun Heo Subject: Re: ATA 4 KiB sector issues. Message-ID: <20100317025101.GA13339@guarana.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1268752993.21384.23.camel@mulgrave.site> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org James Bottomley wrote: > On Wed, 2010-03-17 at 00:20 +0900, Tejun Heo wrote: ... > > Well, the thing is that > > > > * Anything remotely modern (>= XP) doesn't give a hoot about cylinder > > alignment. > > > > * Anything older (<= 2000) is very likely to get confused with custom > > geometry starting from the BIOS itself. For those cases, the only > > thing we can do is aligning partitions to cylinders abiding BIOS > > supplied geometry parameters which will usually be 255/63. > > > > So, using custom geometry doesn't help compatibility at all. > > Our partitioning tool still obey the integral cylinder rule ... we can > argue about whether they should, but what we need is a strategy for > fixing what is rather than what should be. James / Tejun, Can't we fix the problem by defaulting to aligning partitions to start on an LBA that is a multiple of 64260 ? Such partitions will always be 4KiB-aligned, *and* start-of-cylinder aligned (assuming 255/63, as seems to be the norm). Sure, that reduces your partition granularity to almost-32-MiB, but that's pretty small potatoes these days (and it's only a *default*, so you could always override that if you really cared, and didn't need the compatibility). - Kevin