On Fri, Mar 27, 2009 at 10:37 AM, Edwin Lee <[email protected]>wrote:
> > Hi Ole, Thanks for the advice! > > > If you had not, then I have successfully made a bad hard > > drive start > > one final time by putting it in the freezer overnight. It > > might be > > worth trying if only for the practice. > > This sounds interesting. i think i will try this out over the weekend, just > for the heck of it! Just out of curiosity, what is the reasoning behind > this? > Hmm, interesting. Google says: http://www.pcmech.com/article/data-recovery-data-loss-and-drive-failures/ http://www.trisweb.com/archives/2005/06/15/hard-disk-recovery-the-freezer-trick/, > i found this document from Corsair through Wikipedia ( > http://www.corsairmemory.com/_faq/FAQ_flash_drive_wear_leveling.pdf). It > talks about wear levelling, and at the last paragraph: > > <quote> > Will my Corsair USB Flash drive last more than 10 years? > > Yes. All Corsair flash drives are built with memory components that can > handle AT LEAST 10,000 write cycles; typically they will handle an order of > magnitude more than this. So, this means that in order to exhaust the drive > in ten years, one would have to write to EVERY BLOCK in the device about 2.7 > times per day, every single day. We simply can’t conceive of such a usage > scenario; this would mean that on a fairly typical 8 GByte drive, one would > need to write over 21 GBytes of data to it every day for ten years! USB > flash drives simply are not used in this way. > > If one thinks he or she might actually try this, we suggest buying a > Corsair Flash Voyager GT or a Corsair Flash Survivor GT USB drive. They are > built with components guaranteed for 100,000 write cycles. With these, one > can write over 210 GBytes of data to the drive each day, for ten years! > </quote> > > i think i may get one of these Corsair drives! Based on my usage, it should > last at least as long as the portable hdd. My *impression* is that some types of flash storage (moreso for the embedded variety) are directly addressed by the OS; for these, using jffs2 or some other file system that implements wear levelling is a good idea to ensure longevity. However, most consumer flash drives have a controller that implements wear levelling, and they can therefore be relatively safely used with standard filesystems like ext*, or even fat / ntfs. Having said that, operating systems and file systems can do lots of writes even when you're not doing anything, with journalled filesystems even more so. (Someone more knowledgeable than me, please correct if I'm mistaken) > Just another update, this morning, i tried plugging in the USB hdd again > (without trying the freezer technique yet), and it was detected! So i > started copying out the other stuffs as well, and it managed to do that, but > ran into the same previous problems about halfway through. hmm... > If the problem is bad sectors, I'd suggest dd_rescue to get a disk image of whatever is readable. Be prepared for it to run a long time ( >> hours) and for it to be totally unusable thereafter.
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