Recover Your Data with Software
When dealing with a software data loss, the first and most important
thing to keep in mind is not to work with the drive in question. Every
second that the drive is connected to a running system is a second that
you lose your chances at recovery. Your operating system is reading and
writing to your drive constantly, whether you're actively doing
something or not. Now that your system is seeing the deleted data as
‘free space' it will happily overwrite this area—along with your chances
of recovery.
Shutdown the machine connected to the drive
you've deleted data from. Now that your drive is ‘safe' you can make a
clone of the drive and attempt the recovery from the clone. There are a
number of ways to clone the drive, some easier and quicker than others.
Scan the clone with a few different recovery programs. There are
numerous options here, both free and paid-for packages are available.
Recuva is a good free option, while Zero Assumption Recovery works well
if you want to splash out a few dollars. Recover Your Data with
Hardware
Having covered the ‘deleted data' section of data recovery
is all good and well, but what happens if your drive is not even being
detected by your machine? Or your machine can see the drive, but just
hangs when you try to access it? What about if the drive is completely
dead and won't even spin up? Let's briefly cover the main components of a
drive, see which components can fail, and what symptoms each failure
might exhibit.
PCB: This is the (often green) circuit board
attached to the bottom of your drive. It houses the main controller (the
equivalent of your computer's CPU) along with many other electronic
controllers. This is the interface that turns your 0s and 1s from the
platter into usable data that your computer can understand.
Platters: Your drive contains one or more thin, circular platters. These
spin around at anywhere between 5,900rpm to 7,200rpm on consumer drives
and are the media that actually store your data. Made of glass or some
form of alloy and coated with a magnetic layer, they can store anything
up to 4TB of data.
Head assembly: Data from your drives'
platters is read by means of a series of read and write heads. While in
operation, these heads are not actually in contact with the surface of
the platters. In fact, they ‘fly' nanometers above the surface of the
disk, reading and writing data. Typically a drive will have 2 heads per
platter, so a large capacity drive with 3 platters will be paired up
with 6 heads, one for each side of each platter. If these heads fail
physically or the drive is dropped or knocked over, the drive can
experience a ‘head crash' where the heads no longer fly over the
platters, but instead make contact with the surface and destroy your
data at a few thousand revolutions per minute.
Firmware:
Your drive runs its own mini operating system in order to deal with all
of the data and operations required to access it. Most of this firmware
is stored on the platters. A small portion is stored on the PCB, which
is required when the drive starts up. Firmware can go wrong, leading to
inaccessibility
of your
data. Unfortunately hard drive firmware is not similar to your mobile
phone or tablet—you cannot just update or reflash it. Each drive has its
own unique modules and parameters and is highly complex in nature.
Now that we understand the basic components of a hard drive let's look
at some common failures and symptoms you might experience, determine
which component could be causing the problem, and see if we can tackle
some of these problems DIY style.
If Your Drive Isn't Spinning Up At All
This is the one instance where you have a relatively good chance of
resurrecting your drive if you're prepared to put in some time and
effort. If the drive does absolutely nothing when you apply power to it
(no noises at all), it is 99% a PCB problem. With older drives, you
could sometimes find a matching PCB from another matching drive, swap it
over, and voila. However, on new drives, technology and architecture
have changed and each drive contains microcode unique to the drive it's
attached to. Simply swapping the PCB with a matching, working equivalent
has almost no chance of working and can be outright dangerous to your
data.
There are two main causes of failure here, either a TVS
diode (fuse) has shorted due to overvoltage, or a vital component on the
PCB has failed. Hard drive PCBs often have two TVS diodes which act as
fuses to protect your drive in the event of a power spike. There will
most likely be two of these: one for the 5v and one for the 12v rail. If
you accidentally plugged in the wrong power adapter to your external
drive, or you experienced a power surge, a TVS diode might have
sacrificed itself. If the shorted TVS diode is the only casualty and the
rest of the PCB components are OK, then simply removing the shorted
diode is enough to bring the drive back to life.
You can test
this with a multimeter—if the diode reads zero ohms, or close to it,
then it has indeed shortened. When shorted these diodes often have a
noticeable burnt smell and might have visible burn damage. Note that
when a TVS diode is removed the drive is no longer protected, so ensure
that the power supply you connect to the drive is correct and healthy.
If the TVS diodes don't smell burnt and show the correct digits
when measuring them, then the problem is the PCB itself. A replacement
PCB is required, but not just a straight swap. There is an 8 pin ROM
chip on most PCBs that contains unique firmware info that is required to
start up the drive. This needs to be moved from the old PCB to the new
in order for the replacement to work. Some hard drives, especially
Western Digitals, do not have this 8 pin chip—the firmware is stored in
the main controller which is virtually impossible to move.
If
you want to replace the PCB then you'll need to fine a matching
replacement and have the ROM chip moved. There are many online providers
that will sell you a matching PCB. Some of them even offer to move the
ROM chip for you, saving you the hassle of soldering and possibly
damaging the chip. If the PCB was the only damaged component and the
drive's internals are OK, then after the replacement and ROM swap, your
drive should be up and running again. Another PCB-related item to check
are the head contacts. Sometimes they corrode with time, but are easily
cleaned with a rubber eraser. If Your Drive Is
Spinning Up and Making Clicking Noises
This is a serious failure and
indicates a failed head or heads. It could also mean that your drive
has suffered from platter damage if a head crash has occurred. Either
way, this is a job for the pros. The drive will need to be opened in a
clean room environment in a lab and a replacement head assembly fitted
in order to try and recover your data. If your drive is clicking, it's
best power it off and leave it in this state until you can send it to a
professional recovery company. Powering it up in this state could
degrade the disk further, to the extent that it's no longer
recoverable.If Your Drives Spins Ups and Is Detected by Your Computer,
But Hangs When You Try to Access It
This usually means that the
magnetic media is degraded. Basically, there are a large amount of bad
sectors that the drive is trying to read, failing to do so, and hanging.
This is a common problem that occurs over time and can be worked
around, but only with professional data recovery equipment, more
specifically a hard imager. If you look at the SMART values of the drive
you'll notice and large amount of reallocated sectors to confirm your
suspicions. If the data is important then send it off to the pros.
If you want to have a crack at it yourself (and risk making the problem
worse or losing your data altogether) then you can try a software
imager that can work around bad areas. Seeing that software commands
ultimately goes through the BIOS, the effectiveness is limited. The best
option if you want to go this route is a free Linux application called
dd_rescue. It can skip bad areas and image in reverse.
If Your Drive Makes a Beeping Sound When You Power it Up
The beeping sounds you are hearing is the motor trying to spin the
drive up and failing to do so. This is caused by one of two things, both
serious mechanical failures. The most common is what's known as
stiction. The heads of your drive park either in the center or on a ramp
at the edge of the drive when not in use. Remember, the heads don't
make contact with the data area of the platters, they fly just above.
Sometimes, the heads can fail to park properly and the platters stop
spinning with the heads still over the data area. Because of the
extremely smooth surfaces of both the platters and heads, they literally
stick to each other, hence the name stiction. The drive needs to be
opened up in the lab, heads carefully removed and most likely replaced,
definitely not a DIY job. The other cause could be seizure of the motor
spindle. This is the spindle around which the platters rotate. It can
become seized if the drive suffers a hard knock or drop. It's not a
particularly common fault, except for Seagate drives as they have a
particularly fragile spindle. There are two ways for this problem to be
resolved, both of which require pro intervention. Either the spindle can
be replaced or the platters are moved to a new hard drive casing along
with heads, PCB, the works.
If Your Drive Sounds Normal but is Not Detected, or is Detected as the Wrong Capacity
This normally indicates a problem with some area of the firmware.
Either it's not being read properly which could actually be head
problem, or there is some corruption that needs to be resolved. A few
years back there was a well-known bug with Seagate 7200.11 drives with
firmware version SD15 known was the BSY bug. Googling this provide a
wealth of info of the huge amount of failures were caused by this
firmware glitch. There was a DIY solution for this particular problem,
but with today's drives there is nothing that the end user can do but to
send your drive in for professional help.
So, there are a few
instances where you can attempt to recover your own data. If you've
accidentally deleted your data then you might be in luck. If the drive
is completely dead and won't even power up then you could go the DIY PCB
route if you wish to tinker. Other than that, if your drive is making
unusual noises or acting in a peculiar manner, you'll need to hand it
over—together with some hard earned cash—to a data recovery
professional. Remember, ANY attempts at data recovery are risky. If the
data is important, take it directly to the professionals.