From owner-freebsd-hackers@FreeBSD.ORG Mon Aug 22 17:20:54 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A460716A41F for ; Mon, 22 Aug 2005 17:20:54 +0000 (GMT) (envelope-from garyj@jennejohn.org) Received: from peedub.jennejohn.org (J8aea.j.pppool.de [85.74.138.234]) by mx1.FreeBSD.org (Postfix) with ESMTP id C239C43D45 for ; Mon, 22 Aug 2005 17:20:53 +0000 (GMT) (envelope-from garyj@jennejohn.org) Received: from jennejohn.org (localhost [127.0.0.1]) by peedub.jennejohn.org (8.13.4/8.11.6) with ESMTP id j7MHKpNb022773 for ; Mon, 22 Aug 2005 19:20:52 +0200 (CEST) (envelope-from garyj@jennejohn.org) Message-Id: <200508221720.j7MHKpNb022773@peedub.jennejohn.org> X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.0.4 To: freebsd-hackers@freebsd.org In-reply-to: Your message of "Mon, 22 Aug 2005 17:55:42 +0200." <5FFDC44D-F094-4856-8FAC-4D14EB77B47A@sarenet.es> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Date: Mon, 22 Aug 2005 19:20:51 +0200 From: Gary Jennejohn X-Mailman-Approved-At: Tue, 23 Aug 2005 11:54:37 +0000 Subject: Re: IBM Active Protection System Approach X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Gary Jennejohn List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Aug 2005 17:20:54 -0000 Borja Marcos writes: > > Søren Schmidt writes: > > I think this will need to be tailored to the exact type of "mishap" > > one wants to protect against. > > I think that the main purpose of the shock detection system is > to allow data to be recovered from the disk in case the laptop is > broken. By parking the heads asap you can avoid damaging the plates > with the head. > > At least that's what I read. The disk won't be necessary usable > after being dropped, but at least the plates should be readable. > > In that case, priority number one would be a fast parking of the > head. However, it could lead to a worst-case data loss with > softupdates and the disk cache, isn't it? > It seems to me that the worst-case scenario, dropping the laptop, would result in extremely high G-loading in microsecomds rather than milliseconds. Not much can be done to save the disk in such a short time. A scenario where the user bumps the laptop while in use might be helped, though. --- Gary Jennejohn / garyjATjennejohnDOTorg gjATfreebsdDOTorg garyjATdenxDOTde