Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261663AbVEPOdi (ORCPT ); Mon, 16 May 2005 10:33:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261668AbVEPOdi (ORCPT ); Mon, 16 May 2005 10:33:38 -0400 Received: from mail.dvmed.net ([216.237.124.58]:54939 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S261663AbVEPOdg (ORCPT ); Mon, 16 May 2005 10:33:36 -0400 Message-ID: <4288AF3A.2000008@pobox.com> Date: Mon, 16 May 2005 10:33:30 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.6) Gecko/20050328 Fedora/1.7.6-1.2.5 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Matthias Andree CC: linux-kernel@vger.kernel.org Subject: Re: Disk write cache (Was: Hyper-Threading Vulnerability) References: <1115963481.1723.3.camel@alderaan.trey.hu> <20050515145241.GA5627@irc.pl> <200505151121.36243.gene.heskett@verizon.net> <20050516111859.GB13387@merlin.emma.line.org> In-Reply-To: <20050516111859.GB13387@merlin.emma.line.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: 0.0 (/) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1029 Lines: 29 Matthias Andree wrote: > On Sun, 15 May 2005, Mikulas Patocka wrote: > > >>Note that disk can still ignore FLUSH CACHE command cached data are small >>enough to be written on power loss, so small FLUSH CACHE time doesn't >>prove disk cheating. > > > Have you seen a drive yet that writes back blocks after power loss? > > I have heard rumors about this, but all OEM manuals I looked at for > drives I bought or recommended simply stated that the block currently > being written at power loss can become damaged (with write cache off), > and that the drive can lose the full write cache at power loss (with > write cache on) so this looks like daydreaming manifested as rumor. Upon power loss, at least one ATA vendor's disks try to write out as much data as possible. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/