Data
recovery companies thrive on their customers' lack of information and
often get away with charging obscene rates for any recovery, regardless
of complexity. This article answers the following essential questions
users must ask before purchasing data recovery services: How do hard
drives work? How can they fail? What are the chances of successful
recovery and how much can I expect to pay?
Know what you're dealing with
The world of data recovery is a big mystery for most consumers and even
some IT professionals. This is largely because hard drives themselves
are complex devices and their technological specifics are not generally
well known. Data recovery companies thrive on their customers' lack of
information and often get away with charging obscene rates for any
recovery, regardless of complexity. I hope this article will be a
helpful resource for consumers and professionals alike. I provide some
basic information about data recovery by shedding some light on how
hard drives work, how they can fail, what are the chances of successful
recovery and how much the user can expect to pay. This information will
enable the user to make an informed decision when choosing a data
recovery company.
A bit about Hard Drives
A computer hard drive stores data on metal oxide platters which spin up
to 10000 revolutions per minute. An actuator arm contains the 'head'
which reads and writes the data in the form of magnetic charges one
millionth of an inch above the surface. Any given drive can have
multiple read and write heads and each head can 'crash' independently.
A head crash occurs when the read/write head comes in contact
with the platters of the disk (more on head crashes below). As
manufacturers strive to cram more space on hard drives without
increasing their physical size, the data gets written increasingly
closer together, making for very difficult recovery should one or more
heads crash. The brain of the hard drive is its controller board and this is unique for each individual hard drive. One other detail
worth a mention is the service track of a hard drive. This is an area
located on the outer part of the disk platter and it contains the
drive's firmware zone. The firmware of a hard drive is the
information used by the computer to communicate correctly with the
drive. These are the main components that make a hard drive work, now
let's talk about what can go wrong.
There are many ways in which a hard disk can fail
Hard drives are extremely fragile and can suffer failures in many
different ways, leading to a loss of data. The five most common types
of drive failures are: logical errors, mechanical failure, electronic
failure, firmware corruption, and bad sectors, or any combination
these. Least severe of these is usually data loss due to logical errors.
Logical errors are often the simplest and sometimes the most
difficult problems to deal with when recovering data. They can range
from an invalid entry in a file allocation table, a simple problem that
needs little work; to severe issues such as the corruption or loss of
the entire file system. Logical errors can be spotted when files
become inaccessible, there is a delay in starting up the computer, and
programs do not run properly. Logical errors are often seen as
simple because there is nothing wrong with the physical drive leading
users to try recovering it themselves by using third party software.
This is quite risky, however, as running such software on a damaged
drive can result in total loss of data. The most effective way to
prevent logical errors on your hard drive is to regularly use the Disk
Defragmentation tool in your operating system. For more comprehensive
information on preventing data loss, visit the tips section of our website.
Recovering a drive with logical errors can be simple and quick,
however if the problem requires manual bit-by-bit reconstruction of the
data, it can also be quite complex and time consuming. Normally,
logical errors are in the lower end of the price range as they do not
require manual disassembly of the drive, however there are cases when
logical failures end up in the higher end of the price range. The
bottom line with logical errors is the sooner they are caught and the
less a user tampers with the drive, the better the chances for a quick
and thorough recovery.
Mechanical failures are often much more serious than any other
failure and frequently lead to a partial or even total loss of data.
The most common type of mechanical failure is a head crash, which is
when the read/write head comes in contact with the disk platter. Head
crashes can be caused by a variety of reasons, including physical
shock, static electricity, power surges, and mechanical read/write
failure. Mechanical failures are detected by a constant clicking or grinding noise coming from the drive. If you suspect mechanical failure, you must immediately shut down your computer and call a data recovery company for advice.
Mechanical failures are usually the most severe and most challenging to recover from.
All mechanical failures require physical disassembly of the drive. The
replacement of a read/write head is one of the most complex and costly
procedures that can be performed by a data recovery engineer,
especially with larger capacity drives. The chances of recovery depend
entirely on how much damage the drive has sustained, however they can
be quite good. A crashed head does not mean that all your data is lost! Once again, the sooner you catch a mechanical problem and turn off your
drive, the more of your precious data is likely to be rescued.
Electronic failures are most common after a power surge or due
to some other electric problem, and the most common type is control
board failure. A power surge can knock out the control board, making
the drive undetectable in the BIOS. Because each drive is fitted with a
unique control board, recovery of this type is relatively complex.
However, the good news is that normally once the control board issue is
fixed, the data is usually 100% recoverable.
Recovering a drive that has suffered from an electronic failure can be time consuming,
mainly because the specific problem takes some time to diagnose. Once
diagnosed, though, the recovery is usually not tremendously complex and
would probably land in the mid-range in terms of price. Most of the
time, we are able to achieve a 100% recovery from drives that have
suffered an electronic failure.
Firmware corruption is caused by logical problems or physical
damage to the firmware zone on the disk platter. When the firmware
becomes corrupt, the computer is often unable to properly communicate
with the hard drive, and drive is not recognized in the BIOS.
Fortunately, when the drive fails due to firmware corruption, the data
is usually fully recoverable once the drive has been repaired.
Recovering a drive that has suffered from Firmware corruption is
possible with the use of our proprietary technology. Because the
firmware information is isolated on the outer rim of the disk, most of
the data can be recovered successfully. The complexity of recovering a
drive that has suffered from firmware corruption depends on the amount
of damage suffered by the service track on the disk's platter. Expect
the cost of this type of recovery to be in the mid- to high-price range.
Bad sectors are a common fate of all hard drives.
Eventually, all drives develop areas that are no longer functional and
when this happens, they are isolated by the operating system. Bad
sectors are very much like bumps in the road, areas which are avoided
by the read/write head and which are no longer accessible to the user.
If mission critical data exists on the drive, we recommend to backup as
soon as possible, as the formation of bad sectors often indicates the
impending demise of the drive. Finally, and most importantly, do NOT
under any circumstances run the ScanDisk or Chckdisk utilities when
data becomes inaccessible. These utilities are designed to fix only
file system errors and not any other types of errors, so if your hard
drive has suffered from bad sectors, these utilities only make things
worse.
Bad sectors are accessible
We are able to recover drives with bad sectors using our proprietary
mirroring technology. The process often involves manual mirroring
bit-by-bit, which can be time consuming. The price of this type of
recovery will generally be in the mid-range of the pricing schedule.
I hope the above explanations are of some use to all computer users.
The basic fact is that data loss happens to everyone. Every hard drive
crashes, and often when you least expect it to. Backup is essential for
end-users and business users alike, and there are many excellent ways
to back up your data. But if you've lost data, attempt to understand
the problem before calling a data recovery company. Be informed, save
your money, get your data back.
