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Alan Storm
Asked: 2009-08-14 09:14:40 +0800 CST

How do data recovery firms recover data from a "dead" hard disk?

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The hard drive in my laptop just died, and it's been about a week since I ran a full backup.

I know there are companies that specialize in data recovery from dead hard disks. I'm curious how they do this. What steps would one of these companies take if I brought in my drive and told them "Hey, this is dead, get me my stuff back"?

I'm looking for a high level answer, as I imagine some of the actual details could fill a book :) I'm not planning on doing this myself, it's more a curiosity about other people's jobs and the voodoo they use.

backup

5 Answers

  1. It depends on what's wrong.

    In some cases, the part that's "bad" can be replaced (in a clean room), or the platters can be moved from one drive to another (again, in a clean room).

    Worst case scenario, I have heard of microscopic evaluation of the platter surface, though I can't imagine what that would cost.

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  2. Another thing, if its not mechanically bad, but electronically bad, the board can be swapped from an identical drive as well, usually without opening the casing itself.

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  3. Best Answer

    Here's a general high level view:

    1) If platters are spinning and a BIOS can identify the drive try software. They will likely a 'low level' software program to see if the data is recoverable. Sometimes they get lucky and Steve Gibson's SpinRite will make things work. :)

    2) If platters are not spinning and/or the drive is not recognized by BIOS then they will likely replace the controller board on the drive. If they have one in stock this is pretty easy. They will then test if that changed anything.

    3) The desperation move is to remove the platters. This is not trivial and is only done after other options fail. The platters will be put in another drive and the data will be attempted to be removed.

    Much of what you pay for with drive restoration is the expertise, their huge stock of drives and controllers, and the clean room. Those make running a drive restoration service fairly capital intensive.

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  4. I've had to send off a few drives for people who's data wasn't recoverable by software. The particular company sent them off to a clean room, pulled the platters, put them in another drive, and recovered the data that way. I believe you had a few options for media for the recovered data. I worked for a university that had a contract with Dell, and this company was Dell's go to for this and gave a discount. With that, I want to say it was around $2,000. So, keep that in mind.

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  5. They crack the case and pull out the platters and do the recovery in a clean room. The platters will be put into a known good spindle and data is recovered that way. They can get most of the data, but if the platters are damaged, you might only get 80-85% of the data from the disk. It might be the data that you need!

    -JFV

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