Date: Wed, 26 Aug 2009 13:01:20 -0400 From: Jerry <gesbbb@yahoo.com> To: freebsd-questions@freebsd.org Subject: Re: hard disk failure - now what? Message-ID: <20090826130120.5d30aa8d@scorpio.seibercom.net> In-Reply-To: <20090826161038.GE11739@phenom.cordula.ws> References: <1338880b0908241129p75b6845cg26d21804e118364@mail.gmail.com> <ade45ae90908241313y495832edkd87004485602a42e@mail.gmail.com> <20090824224003.0b5ac2df.freebsd@edvax.de> <ade45ae90908241351o56e6649cv4dfc50a8fee5aeff@mail.gmail.com> <20090826161038.GE11739@phenom.cordula.ws>
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On Wed, 26 Aug 2009 18:10:38 +0200 cpghost <cpghost@cordula.ws> wrote: > On Mon, Aug 24, 2009 at 02:51:41PM -0600, Tim Judd wrote: > > >> Buy spinrite, no matter what. > > > > It's OS/FS independent. it works on the bits stored on the magnetic > > platters, NOT on a filesystem. TiVo, Linux, BSD and Mac OSX drives > > are treated the same. Bits on a magnetic platter. It's recovery > > stems from the randomization and movement of the head to the sector > > in question that allows it to salvage any bits it can (for example, > > other recovery will abandon 512bytes if 1 bit cannot be read. > > spinrite will recover 512bytes-1bit to a hard drive's spare sector > > once spinrite says "i'm done working with this sector".) It leads > > to a very successful rate. > > (Disclaimer: I'm not familiar with spinrite.) > > 512bytes-1bit may be read back, but you can't be sure that those are > the correct bytes! IIRC, sectors are usually protected by some kind of > ECC. Simply ignoring the ECC and reading raw magnetic data will all > too often result in corrupt sectors. > > Of course, if you have out-of-band error correction or at least error > detection mechanisms (like .PAR or md5/sha1 checksums), raw magnetic > recovery is better than nothing, if you're desperate. > > -cpghost. I have used Spinrite several times with excellent results. In fact, I recently used it to recover a Laptop drive that had become unusable. Spinrite tries to turn off ECC if possible. It is not the cheapest product; however, it works better than anything else I have tried on bonked discs. Use it on its highest recover level and it will recover the drive; although it may take a while. http://www.grc.com/intro.htm -- Jerry gesbbb@yahoo.com Lord, defend me from my friends; I can account for my enemies. Charles D'Hericault
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