A friend has given me a hard drive that is no longer being recognised by her PC and there is data that she would like to recover.
I've plugged it in to my own PC and it appears in the bios but nowhere else (under Windows XP). I've tried running Knoppix and seeing if I can mount the drive under that but although it appears in the list of drives, it won't mount.
I've tries a couple of software packages, one of which says that the drive has lost its partition but can see data files on the drive. Unfortunately it only allow 500 megabytes of recovery for free, after that it cost £79 which is more that my friend is prepared to pay. I have tested it on some files and it does appear to be able to recover stuff.
I've tried another freeware package called "findandmount" but it can't find anything.
I used ddrescue on a Linux system booted from USB when my friend had hard disk problems on his laptop.
formatting link
It was able to recover all of the data that mattered to him (everything under my documents essentially), even though a lot of the drive including most of the OS files were unreadable.
I would use Linux or some other Unix-like OS to perform the recovery, because Windows has a nasty habit of writing to every disk it sees if only to add a recycle bin or something. Writing to a potentially damaged disk can make things worse. In Linux, you can leave a disk unmounted and use tools that only read it.
Somewtimes, but only as a last resort, putting a drive in a freezer (in a bag) makes it readable. I've had that work once, but it is a last resort- but probably better than screwdrivers.
Only time I took a screwdriver to a drive was to replace its drive electronics, Open the platters up and its dead anyway - they are sealed for a reason.
Step 1. Take a bit-for-bit copy using dd or better dd_rescue / ddrescue. Then work on the copy.
Do not attempt to repair the original disc. One reason is the hardware might be failing, and recovery activity could cause it to die sooner. Another is that recovery tools might get it wrong and break things further - in which case the original disc is the only backup you have.
When you have the data somewhere safe, you can then make a judgement on whether the physical mechanism is safe enough to reuse. But that's then entirely decoupled from the condition of the data.
Is it possible to get the data from a failed disc recovered? Even one which has been fiddled with? I do realise this wouldn't be cheap.
One place I approached could only do it if swapping the electronics board from an identical one worked.
It's all very odd. Some seem to say you have to smash an HD to bits to prevent it being read. Then when you do want a failed one read, it's only possible with a very simple fault.
It'll depend on the failure. I had a disk that failed after a thunderstorm (I was away the w/e and so had not powered the machine down). My local Apple store had the same drive with a head crash, so they sold me the logic board for £10, which fixed the problem. This was in 1994.
It is possible to retrieve data. There's two ways: one is to use the existing heads and drive them from test equipment (that maintains the drive geoemetry, since the data tracks are matched with the heads that laid them down). Or you can mount the platters in a test jig with new heads - which means they then have to be calibrated against the data tracks.
That's all in 4/5/6 figures territory. It also isn't quick, so you might get enough access to get a few documents off, but recovering the whole N TB is going to be very slow and expensive.
That has limited success nowadays. There are some people who do no-fix-no-fee repair services which is not a good idea: maybe hitting it with a hammer will fix it, if not I'll give you the pieces back and there's no charge.
All this stuff with freezers and swapping boards and giving it a thump fall into the same category IMHO: last resorts for data you aren't prepared to spend money on. The problems come when people don't try the first resorts first.
If you want to destroy data, to a first approximation just overwrite it (ATA secure erase is good). The idea that the disc data needed overwriting 7 times dates from 1980s and is no longer true.
If the drive died and you think someone might try and spend 10K to get your data off, simply removing the platters is enough. Misaligning the platters increases the cost substantially.
If the disc is dead and the data is worth spending millions on to recover it, then by all means shred the drive.
For most of us, simply wiping the drive is good enough. Even better, use disk encryption and simply delete the key. Much less hassle.
+1. I was able to copy quite a few files from a "dead" disk which wouldn't boot until I used the freezer method. If you are lucky, you can put it in the freezer a few times, but you soon start finding you are following the law of diminishing returns...
What if the disk you want to recover is the only one in the computer? Can TestDisk be run from a bootable CD/DVD or USB stick? (I can't see any instructions on their website.)
On at least one occasion I got a drive to find its boot sector and start working by removing the top and applying very gentle pressure to the head actuator. This was a long time ago and the capacity was
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