Date: Tue, 23 Aug 2005 07:05:00 -0500 From: Eric Anderson <anderson@centtech.com> To: Gary Jennejohn <fbsd@jennejohn.org> Cc: freebsd-hackers@freebsd.org Subject: Re: IBM Active Protection System Approach Message-ID: <430B10EC.1080006@centtech.com> In-Reply-To: <200508221720.j7MHKpNb022773@peedub.jennejohn.org> References: <200508221720.j7MHKpNb022773@peedub.jennejohn.org>
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Gary Jennejohn wrote: > Borja Marcos writes: >=20 >>>S=F8ren Schmidt writes: >>>I think this will need to be tailored to the exact type of "mishap" =20 >>>one wants to protect against. >> >> I think that the main purpose of the shock detection system is =20 >>to allow data to be recovered from the disk in case the laptop is =20 >>broken. By parking the heads asap you can avoid damaging the plates =20 >>with the head. >> >> At least that's what I read. The disk won't be necessary usable =20 >>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 =20 >>softupdates and the disk cache, isn't it? >> >=20 >=20 > 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. The idea is for the laptop to recognize when it has begun a fall or=20 other sudden change in acceleration, so it parks the heads well before=20 impact time. > A scenario where the user bumps the laptop while in use might be > helped, though. Eric --=20 ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------
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