From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 23 07:04:21 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 781FF16A41F; Tue, 23 Aug 2005 07:04:21 +0000 (GMT) (envelope-from julian@elischer.org) Received: from delight.idiom.com (delight.idiom.com [216.240.32.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id 33B3743D45; Tue, 23 Aug 2005 07:04:20 +0000 (GMT) (envelope-from julian@elischer.org) Received: from idiom.com (idiom.com [216.240.32.1]) by delight.idiom.com (Postfix) with ESMTP id 96CDD1FDF10; Tue, 23 Aug 2005 00:04:20 -0700 (PDT) Received: from [192.168.2.2] (home.elischer.org [216.240.48.38]) by idiom.com (8.12.11/8.12.11) with ESMTP id j7N74I5d056905; Tue, 23 Aug 2005 00:04:19 -0700 (PDT) (envelope-from julian@elischer.org) Message-ID: <430ACA72.7070303@elischer.org> Date: Tue, 23 Aug 2005 00:04:18 -0700 From: Julian Elischer User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.7) Gecko/20050424 X-Accept-Language: en, hu MIME-Version: 1.0 To: "M. Warner Losh" References: <5FFDC44D-F094-4856-8FAC-4D14EB77B47A@sarenet.es> <430A8E2B.6040408@elischer.org> <20050822.213857.78011913.imp@bsdimp.com> In-Reply-To: <20050822.213857.78011913.imp@bsdimp.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org, sos@freebsd.org, borjamar@sarenet.es Subject: Re: IBM Active Protection System Approach X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 Aug 2005 07:04:21 -0000 M. Warner Losh wrote: > In message: <430A8E2B.6040408@elischer.org> > Julian Elischer writes: > : You have about 1/4 a second to get the heads in once you detect that > : you are falling. > > Yes. For a 4' fall, we know it takes 1/2 a second to reach the > ground: > s = 1/2 a t^2 + v0 t + s0 > > s0 = 0, a = 32 f/s^2, v0 = 0, s = 4, solve for t gives 1/2 a second to > make the fall. Sos was saying 10's of ms to retract the heads, so > even a 300ms response time wouldn't be fatal, but it would be pushing > the limits. > > For a 2' fall, you have even less time. More like 350ms. 1' is 250ms... > > Warner I decided that you assume it's being picked up and slips out of your grasp and then dropped a pen from about 2' and said "yep, something like 1/3rd of a second.. I'll say something shorter than that" :-)