From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964891AbVHSKHF (ORCPT ); Fri, 19 Aug 2005 06:07:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964917AbVHSKHE (ORCPT ); Fri, 19 Aug 2005 06:07:04 -0400 Received: from pythagoras.zen.co.uk ([212.23.3.140]:391 "EHLO pythagoras.zen.co.uk") by vger.kernel.org with ESMTP id S964891AbVHSKHB (ORCPT ); Fri, 19 Aug 2005 06:07:01 -0400 Message-ID: <4305AECE.3020508@dresco.co.uk> Date: Fri, 19 Aug 2005 11:05:02 +0100 From: Jon Escombe User-Agent: Mozilla Thunderbird 1.0.6-1.1.fc4 (X11/20050720) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jens Axboe CC: Pavel Machek , Adam Goode , Alejandro Bonilla Beeche , linux-kernel , hdaps devel Subject: Re: [Hdaps-devel] Re: HDAPS, Need to park the head for real References: <1124205914.4855.14.camel@localhost.localdomain> <20050816200708.GE3425@suse.de> <20050818204904.GE516@openzaurus.ucw.cz> <1124399756.28353.0.camel@lynx.auton.cs.cmu.edu> <20050818213823.GA4275@elf.ucw.cz> <20050819063602.GD6273@suse.de> In-Reply-To: <20050819063602.GD6273@suse.de> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Hops: 1 X-Originating-Pythagoras-IP: [82.68.23.174] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>>>Please make it "echo 1 > frozen", then userspace can do "echo 0 > frozen" >>>>after five seconds. >>>> >>>> >>>What if the code to do "echo 0 > frozen" is swapped out to disk? ;) >>> >>> >>Emergency head parker needs to be pagelocked for other reasons. You do >>not want to page it from disk while your notebook is in free fall. >> >> > >It's still a very bad idea imho, what if the head parker daemon is >killed for other reasons? The automatic timeout thawing the drive is >much saner. > > For hard disk protection, I prefer the idea of the userspace code thawing the drive based on current accelerometer data, rather than simply waking up after x seconds (maybe you're running for a bus rather than falling off a table)... To get the best of both worlds, could we maybe take a watchdog timer approach, and have the timeout reset by the userspace component periodically re-requesting freeze? Regards, Jon. ______________________________________________________________ Email via Mailtraq4Free from Enstar (www.mailtraqdirect.co.uk)