Date: Mon, 22 Aug 2005 19:47:07 -0700 From: Julian Elischer <julian@elischer.org> To: Borja Marcos <borjamar@sarenet.es> Cc: freebsd-hackers@freebsd.org, =?ISO-8859-1?Q?S=F8ren_Schmidt?= <sos@freebsd.org> Subject: Re: IBM Active Protection System Approach Message-ID: <430A8E2B.6040408@elischer.org> In-Reply-To: <5FFDC44D-F094-4856-8FAC-4D14EB77B47A@sarenet.es> References: <OF828DE8D9.036E29C8-ONC1257065.002A679F-C1257065.002CBB28@gateway-inter.net> <A95A177C-8C1B-47F6-8344-B818F6A97EAF@FreeBSD.org> <5FFDC44D-F094-4856-8FAC-4D14EB77B47A@sarenet.es>
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Borja Marcos wrote: >> 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. no, the aim is to detect the LACK of acceleration as the laptop goes into freefall. You have about 1/4 a second to get the heads in once you detect that you are falling. Quick by human standards but an eon in computer terms. > > 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? > > > > > Borja. > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
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