Maybe the title is a bit harsh, but in the past week I have seen an unusually high number of hard drives ruined by avoidable problems. There is nothing more frustrating than knowing the data would have been recoverable if the hard drive hadn’t been tampered with first.
Hard drives are manufactured in a controlled environment. Staff wearing white overalls, gloves, and masks, control machines which are carefully organised to prevent contamination getting inside the hard drive.
To prevent contamination when repairing the inside of a hard drive, it is necessary to use a cleanroom. This is a specially designed system that filters the air and keeps airborne particles to a minimum. A cleanroom is the only safe way to open a hard drive. We have one of these, which allows us to carry out the most intricate repairs without any risk of particle damage.
Before opening a hard drive for internal rework, it is crucial to confirm that there is an internal mechanical problem in the first place. For instance, our data recovery process has numerous tests we can carry out before we confirm that the problem is under the hood. Only then will we open the top cover and check for damage inside. Unlike CDs or DVDs, the internal disks of a hard drive are not designed to come into contact with normal air. Even a fingerprint could mean the difference between a successful or unsuccessful recovery. If you slip with a screwdriver then forget it.
On a percentage basis of all the failed drives we receive (hundreds per year), we only need to go to the cleanroom with around 10%. There are likely to be far less intrusive ways into the data without ever taking off the top cover.
I’ve lost count of the number of times I’ve been told, “It’s an internal fault. The heads are clicking.” Although some drives will click as a symptom of failed heads, there are so many other reasons to cause a drive to click that it is not a reliable way to diagnose problems.
Reasons a hard drive will click
- Electronic fault
- Firmware fault
- Bad sectors
- Weak (but not completely failed) heads
- Problems reading partition info
All of the problems above can be overcome without ever unscrewing the top cover. In fact, removing the top cover will only introduce more doubt to the diagnosis. If the top cover is removed outside of a cleanroom, then not only do the above problems need to be solved, but also new problems of contamination and possibly damage by tools.
(Don’t) Get the discs out
Another common wrong diagnosis is to take the disc pack from one drive and place it into a donor drive. Although this is a correct course of action for some drives, there are some serious implications. First, when the disc pack is built it is clamped together onto the spindle motor. This alignment is so crucial that if you remove one disc at a time, you will never be able to regain this alignment. This was true 20 years ago when the magnetic data was nowhere near as densely packed. Rotate the discs a fraction of a millimetre and you can wave goodbye to all the files.
It is also the case that most of the hard drive firmware is now stored on the discs, so moving them to a new donor will not help if the fault is firmware based.
If you are even considering a destructive course of action, at least get some professional advice first. You don’t need to follow the advice, but at least it gives somebody (maybe me) the option to give a warning. You don’t want to find out later that the data would have been simple to recover, if only…