Date: Mon, 22 Aug 2005 17:26:17 +0200 From: =?ISO-8859-1?Q?S=F8ren_Schmidt?= <sos@FreeBSD.org> To: m.ehinger@ltur.de Cc: freebsd-hackers@FreeBSD.org Subject: Re: IBM Active Protection System Approach Message-ID: <A95A177C-8C1B-47F6-8344-B818F6A97EAF@FreeBSD.org> In-Reply-To: <OF828DE8D9.036E29C8-ONC1257065.002A679F-C1257065.002CBB28@gateway-inter.net> References: <OF828DE8D9.036E29C8-ONC1257065.002A679F-C1257065.002CBB28@gateway-inter.net>
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On 22/08/2005, at 10:08, m.ehinger@ltur.de wrote: > what would be the best approach to implement aps on FreeBSD? > > I got an Accelerometer driver which will deliver data. First =20 > Version is available at > https://sourceforge.net/project/showfiles.php?=20 > group_id=3D138242&package_id=3D160977 > > We have to poll the device for information quiet often to detect a =20 > possible shock early enough to park disk drive heads. Urhm, what type of "accidents" is it we want to protect against here ? It will take several tens of mS to get the heads parked if not =20 hundreds, and the worst case scenario would be that the "accident" =20 will happen just as the heads are on the way to the parking zone =20 which would *really* destroy data on there, unless the disk has =20 special HW to just quickly lift the heads or something. > What else must be done to prevent a possible data loss? I think this will need to be tailored to the exact type of "mishap" =20 one wants to protect against. If this is a way to protect against dropping a notebook on the floor =20 then there won't be time for much else than trying to rush the heads =20 to the parking zone. In other setups a flush of buffers (OS level as well as HW level) =20 could be preferred if power loss or HW failure was imminent. - S=F8ren
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