|  This is a situation that every tech support person has faced or will face at least once: a failed
hard drive.
In this particular case, a user was getting errors like "disk 0 error" and "invalid drive specification." Here were the other facts in the case:
• The data wasn't backed up.
• The problem came out of nowhere.
• The user had accessed Setup and tried to manually enter the settings for the drive type when
"Auto" didn't work.
• There was no startup disk made by this machine.
Reviving a drive like that one—even if only long enough to copy its data before you throw the
drive in the garbage.
There are, broadly speaking three classes of data recovery, Logical, Electronic, and Physical.
• Logical
Where the FAT, NTFS or other file structure has been corrupted either by accident or on purpose or individual filed or folders have gone missing. The hard drive has not suffered damage to the components of the hard drive itself.
• Electronic
Component failure on the PCB (the circuit board on the bottom of the hard drive)in the motor or internally.
• Physical
Internal damage to the hard drive, damaged platters, head crashes, damage to the motor, or head rack signal amplifier.You need a clean room and plenty of experience to have any chance of a successful outcome here.
Logical recoveries are becoming an affordable option for those people who are familiar with the risks involved with data recovery. Software tools that are now available for this task vary greatly in their capability, complexity and cost.
Careful research should be done before any work is done on the damaged hard drive. If you are able, get another hard drive and experiment. Format it, Fdisk it, delete files and partitions and learn how the data recovery software operates under these various conditions.
Before to start work on your own or your clients hard drive back it up, the backup mantra is one that you all should be familiar with by now! There are tools available to backup (or image) a hard drive that has been fdisked!! Use them. Ghost software is not suitable for this task, then perform your recovery attempts on the image not the original.
Some electronic data recoveries are also within the capability of many technically minded people who spend much of their time working around computers. Remember your static strap when removing PCB boards.
A repair of this nature can be as simple as swapping the PCB board. With a board from a matching working hard drive. Data recovery companies keep an inventory of many 1000’s of hard drives for events such as this.
If a PCB swap does not work then the most common problem is that the match was not close enough. In any production run of a particular model of hard drive there could be as many as several dozen changes in firmware upgrades, components on the board, etc.
To have the best possible chance all of the code numbers and letters on the top plate of your drive and its parts donor should be the same. If you have no success then find a reliable data recovery firm near you as you has done as much as you can.
Freeze it
One trick I have learned as a technician, when the problem is data-read errors off the platters themselves, is to freeze the hard drive overnight. It makes the data more 'readable,' but for a one-shot deal. If this data is critical, and you have a replacement hard drive (which, if it's a drive failure, you probably do), then you can hook up your frozen hard drive and immediately fetch the data off before it warms up.
Here are some drive recovery tricks that have worked for me, in the order that I do them. Try booting the drive and copying the data off after every step.
1. Hold the drive upside down, making gravity change the head geometry ever so slightly. Vertical is also another option.
2. Slightly rap the drive with your knuckle, (but nowhere near hard enough to damage the
drive).
3. Try the drive in another machine, (slight drive voltage change assumed to be the miracle worker here).
4. Rap the drive just SLIGHTLY harder than you did above in 2.
5. Freeze the hard drive in the freezer for two hours, and place in a plastic zip lock bag to prevent condensation from forming on the drive when you plug it back into the system, (head geometry, electrical resistance lowered, electrical contact points adjusted, etc., assumed to be
the miracle here).
6. After the drive warms up to room temperature or better, rap it even harder with your knuckle this time.
7. Repeat all of above steps on next day, as sometimes I've gotten data off drive simply by trying again.
Drop it
Sometimes a hard drive that has been running since nearly forever won't spin up after being shutdown for a while. This can be caused by the heads sticking to the platter. As a LAST resort,
I will drop the drive onto a firm surface from approximately eight inches. Inevitably, this will
solve the problem and the drive is useable long enough to remove the data.
Hit it
1. Check CMOS settings to make sure the drive setting are what they should be—the CMOS battery could be dead or the user may have changed the settings. A bad hard drive could cause the Autodetect to misread settings.
2. Boot from a floppy disk and run fdisk/mbr to restore the backup copy of the master boot record.
3. Image the drive with drive copy program to a new drive.
4. It’s possible the HDD controller is bad. Try the drive in another machine.
5. Boot from a floppy attach to a network drive or have a secondary drive installed and if you can access the data copy it off to there.
6. The drive could have a stiction problem. Tap it gently on the sides, preferably with a rubber
mallet.
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