Date: Mon, 22 Aug 2005 21:38:57 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: julian@elischer.org Cc: freebsd-hackers@freebsd.org, sos@freebsd.org, borjamar@sarenet.es Subject: Re: IBM Active Protection System Approach Message-ID: <20050822.213857.78011913.imp@bsdimp.com> In-Reply-To: <430A8E2B.6040408@elischer.org> References: <A95A177C-8C1B-47F6-8344-B818F6A97EAF@FreeBSD.org> <5FFDC44D-F094-4856-8FAC-4D14EB77B47A@sarenet.es> <430A8E2B.6040408@elischer.org>
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In message: <430A8E2B.6040408@elischer.org>
Julian Elischer <julian@elischer.org> 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
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