From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: impact of 4k sector size on the IO & FS stack Date: Sun, 11 Mar 2007 20:44:24 -0400 Message-ID: <45F4A268.3000405@garzik.org> References: <45F48809.2060908@emc.com> <20070312000253.20eab1a3@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Ric Wheeler , linux-scsi , linux-fsdevel@vger.kernel.org, Linux-ide To: Alan Cox Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:46172 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090AbXCLAo3 (ORCPT ); Sun, 11 Mar 2007 20:44:29 -0400 In-Reply-To: <20070312000253.20eab1a3@lxorguk.ukuu.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Alan Cox wrote: > I would be interested to know what the disk vendors intend to use as > their strategy when (with ATA) they have a 512 byte write from an older > file system/setup into a 4K block. The case where errors magically appear Well, you have logical and physical sector size changes. First generation of 1K sector drives will continue to use the same 512-byte ATA sector size you are familiar with. A single 512-byte write will cause the drive to perform a read-modify-write cycle. This configuration is physical 1K sector, logical 512b sector. A future configuration will change the logical ATA interface away from 512-byte sectors to 1K or 4K. Here, it is impossible to read a quantity smaller than 1K or 4K, whatever the sector size is. Jeff