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Creative Data Loss
lewiz writes "An interesting article from the BBC about the crazy things people do when they accidentally delete files. Amazingly one guy froze his hard disk in an effort to retrieve files. Real men don't make backups... but, hell, who needs to if you can resurrect them from the dead ;)"
At least for a little bit? It's helped me recover data from other dead drives a number of times.
Isn't total bollocks, as we say in Britain. The Fujitsu drives that were failing a couple of years ago could sometimes be revived long enough to back them up using this method. The fault was in the drive electronics, not the physical disk.
When I am king, you will be first against the wall.
The myth on freezing is that if the head is stuck, contraction can make it come loose again. I had a drive that stopped responding last week and I did the freezer thing. It mounted one last time, just long enough for me to back it up. I don't know if it was the freezing or just powering it down for an hour, but it worked for me. Posting AC so the flames cant reach me, even in the freezer.
Every computer repair shop knows about this trick. Generally it's not done in a freezer, however, it's done with circuit cooler. This only works (obviously) if it's a problem with the circuit board and that the heads haven't in fact crashed or have some other mechanical problem. This works because it causes connections to expand and work for the temporary period that they're cold. You can also remove the circuit board from a working hard drive and swap it with the non-working hard drive for a permanent effect. If you have a head crash or other mechanical problem, generally you need the services of a clean room to retrieve the data.
I'm a big tall mofo.
If the drive was stictioned, depending on the lubricant, a decent way to rescue it might be
/, /var and /etc. The /usr partition got read errors, possibly due to my whacking the disk.
1) Heat the drive above room temperature. I'm not saying boil it; I put one of those chemical hand-warmers on mine and left it in a box for a while. This should heat it to around 40C.
2) Connect it to your computer, but leave the drive itself out on a desk. May require some monkeying with your case to let it run while open.
3) Turn the computer on. If the drive still clicks when it tries to spin up, tap it on the corner (in a way that would spin the drive if you hit it harder). The idea is to provide some torque to break the static friction of the lubricant and get it spun up.
I rescued (part of) a hard drive this way last year. I didn't get all the data off it, but at least I managed to retrieve
I hereby place the above post in the public domain.
I had a drive die on me at work. The files on it weren't that important, and I got everything from backups anyway, but I decided to try the freezer trick so I'd know in the future if it's worth trying.
The OS was Windows; the drive was buggered enough that it'd just bluescreen when booting. I tried mounting it under a linux box, but it just gave lots of scary "can't read this sector" errors. So I wrapped it carefully in ziplock bags and put it in the freezer overnight.
Sure enough, it worked the next morning (in Linux, anyway; didn't try booting Windows to see if that'd work) for about twenty minutes -- long enough to get a bunch of files off, if this'd been an emergency. Then the errors started up again, so I popped it back in the freezer. After another half hour or so, I tried again and it still worked.
Next trick: I'm going to put some old PC133 RAM in the freezer overnight and see if it'll work in the spare DDR333 slot I've got on my motherboard. Cross your fingers...
Carousel is a lie!
Sheesh I feel old, all you kids here on Slashdot don't even know about stiction.
This really isn't a problem on modern drives, but in the past it would happen. Something that would work to unstick the drive head was to stick the drive into the freezer. This would (presumably by a slight contraction of the platters) allow the drive to spin up. Once the drive was warmed up and spinning, you could then proceed to back up as much of the data as possible before the drive failed.
Now, it's highly unlikely that the person mentioned in the FA had a drive that was suffering from stiction. Modern drives rarely have this problem.
More info here. (Warning: PDF)
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
The bearing gets worn on one side, flipping it over puts the wear on the other side. This was also worked for me several times.
chris@xanadu:~$ whatis /.
/.: nothing appropriate.
for example the thermal shrinking can free heads sticking to the discs (the IBM problem). Or cold solder connections can work again.
Its no repair, but a good trick to try to get the drive running for a hour or two to backup everything.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
there are two major ways freezing can help 1) by cooling the electronics package, pathways that have been messed up will conduct electricity and 2) by cooling the platters, a stuck spindle/head problem can be resolved by the contracting of the metal or mylar coated platters since that moves the heads away from the platters just enough that the hdd can spin up.
Just use rsync to duplicate your local volume to another local, but independent hard disk. Easy enough to do on *NIX with cron, and on Windows use the rsync in cygwin on a scheduled task. Hard disks are cheap these days, and this method gives you a fully local time delayed duplicate (so you can recover deleted files).
Advantages to this method:
I do this, because not only do I have my porn stash to protect, but a few other people's who have it available on their websites which I host!
ND, protector of the pr0n
This statement is forty-five characters long.
At this point one of my tray icons caught my attention... Google Desktop Search. I had been playing with it for a few days and remembered the caching functionality. I opened it up and did a search for the file. Magically, it appeared with a cache and the entire document, in all of it's glory.
This was proof enough for me that aside from the security concerns, desktop search tools do have distinct advantages. Especially instant backups :)
It's actually not that hard, provided you know aproximately how big your partitions were, and you've not changed the virtual layout of the drive (which I did). Most hard drives come in a default virtual configuration of the number of cylenders, heads, and sectors that is not the same as the physical layout. Theoretically, you might be able to improve the accuracy of the scheduler by changing this to the physical layout.
Don't.
If you lose the partition table it will default back to the virtual layout, and your filesystems will be somewhat messed up (partition boundaries may not line up with cylender boundaries, etc). This will lead to some lost data.
Never NEVER NEVER add or remove a PCI card while your MS-Windows XP system is hibernating.
On bootup you could royally screw your disk.
I don't still have the shell script any more, and like I said, I'll bet you can easily find some software to do exactly the same for you. But here's the gist:
:) and save it as a file.
What I basically did was create a brand new gnucash file, then look at the first XML element. Then I wrote a shell script that looped through every single block on the drive looking for that string using dd|grep, just as I said in my earlier post. When the string was found, this first shell script printed the block number.
Now, armed with a list of likely blocks, I piped the list through another script that looked for the date I had last updated the file, again by looking at the XML in the dummy gnucash file for an example. That narrowed it down to two (the original and its backup), so I just used dd to grab that block + 200 blocks (or however many it worked out to, I don't remember after 2 years
I probably used vim to do the cleanup; it's pretty trivial at that point, you just look for the start and end of an XML file.
Hope that helps.
It's rare that you're presented with a knob whose only two positions are Make History and Flee Your Glorious Destiny.