Data Recovery Case Study: Seagate 2


Seagate 7200.11 internal hard drive 500GB in capacity.

Reported Fault:

Drive will not recognise in any computer.


Firmware Failure

The customer posted a hard drive to us for a free analysis to ascertain whether or not a recovery of the data would be possible. When the drive arrived the customer was called to let them know that the hard drive was safe with us and that the analysis would begin shortly. On average, an analysis of a hard drive takes between 24 and 48 hours. From past experience, we know that this model of hard drive has a few weak points where they fail most.

The first stage of our analysis is to remove the printed circuit board and inspect it for obvious signs of damage. We are looking for signs such as burn marks on the insulation or the printed circuit board or bent pins. When we handle a printed circuit board, we need to be careful of electro-static discharge from our bodies. The way to overcome this is by working on an anti-static mat and by wearing an anti-static bracelet that is attached to a ground point and carries the extra current away from your body safely. Components on this model of hard drive are just as susceptible to damage from a power surge as any other hard drive. The most common reason for a power surge on a hard drive is when the client attaches a power adapter that puts through more volts than the hard drive can handle (such as a laptop charger). The correct power supply for a 3.5 inch hard drive like this one should read ’12V-2A’ or ’12V-1.5A’

The next stage is to make sure that there is no damage to the board that we can’t see. We do this with a device called a ‘Multimeter’ or ‘VOM’ (Volt-Ohm meter). Multimeters are used for checking electric currents and for making sure that the correct amount of power is going to the correct place. This stage is to ensure that the PCB does not do anything unexpected when we apply power. In certain situations, failure of diodes and resistors on the printed circuit board can make the hard drive a fire hazard which is understandably dangerous to the technician and can also render the data unrecoverable.

The client was unable to give us any other details on the symptoms of the failed hard drive. This means that before we can turn it on, we need to make sure that the internal mechanisms are not damaged and that by adding power, we won’t be causing further damage to the hard drive. It is entirely feasible that the client could have knocked their system which caused damage to the internal workings.

The hard drive is opened inside our ISO3 class 1 clean air environment. This is important. If we were to open the hard drive in a normal room which does not have filtered air, particles of dust and other contamination could land on the surface of the hard drive. Due to the distance that the read/write heads float above the surface of the platters, even the smallest particle of contamination can cause a lot of damage.

We check for existing damage to the surface of the platters. We check that the read/write heads are in their correct position on the hard drive (Parked on the ‘landing zone’ next to the spindle). We check that the spindle has not seized and that the platters will turn when power is applied. Once we are happy that there is no internal damage, we close up the hard drive. Now we are ready to apply power and turn it on.

We have a specialist hardware/software suite designed to find faults in hard drives and either fix them or get around them so that we can recover the data. We hook up the patient hard drive and turn it on. We listen to the drive as it begins its power on sequence. We listen for unusual noises in the rotation of the platters and for the famous ‘clicking’ noise associated with damaged read/write heads. As the platters reach full speed, the read/write heads fly out and attempt to calibrate themselves with the position on the platters that they think they are supposed to be at. The calibration of this hard drive sounds harsher and longer than it normally would. The hard drive does not register as being ready to accept commands or surrender the data. This is a strong indication that this hard drive is suffering from a well known firmware fault.

The suite that we have allows us to connect to hard drives as if we were the manufacturer. Thanks to this, we can ask the software to test our theory. The program registers that the hard drive does have a problem with its firmware. Once the error has been fixed, we turn the hard drive off and on again and the hard drive registers as ready for reading and writing. The data is recovered from the hard drive and on to a waiting donor hard drive.

It is not expected that any data loss would occur with this type of fault as the data is all still on the platters. This case was a full recovery and the client was very relieved to have her degree back in time for her deadline.