Types of hard disk failure
Firmware corruption
Firmware is the software code that controls and is embedded in the
physical hard drive hardware. It is responsible for the operations
of the hard drive and its activities include configuration, management
of the interaction that takes place between the other components and
the safe powering on/off of the system. At start-up, a hard disk loads
the service data from its firmware zone into RAM and then allows the
drive to report on readiness. If there is damage to these modules,
then the drive will report either it’s family identity or will
not detect it at all.
In the event of such an occurrence, the computer will
be prevented from accessing any data on the hard disk. The benefit
to this is that it is merely an accessibility problem and a firmware
failure does not automatically incur a data loss. Once the drive has
been repaired, it is possible to recover the data.
Electronic failure
Electronic failure usually relates to problems on the controller board
of the actual hard disk. This may be due to the computer actually
suffering a power spike or electrical surge that knocks out the controller
board on the hard disk making it undetectable to the BIOS. This means
that whilst there is an electronic failure, any data stored on the
hard drive will be inaccessible until the problem is fixed. The nature
of this type of problem however, is advantageous as it is a mere hindrance
and data will not be lost or corrupted and is therefore fully recoverable.
Mechanical failure
Mechanical failure is generally considered to be more serious than
electronic failure or firmware corruption as it often leads to data
loss and even complete data loss if prompt action is not taken. There
are numerous types of mechanical failure; these can range from motor
problems to one of the most common types of known failures is a head
crash. A head crash, as it’s name implies, occurs when the read-write
heads of the hard disk collide with the disk’s rotating platter
surface. Often, this can cause damage to both the heads and even the
hard disk itself.
The head normally rides on a thin film of moving air
which is entrapped at the surface of the platter. The platter is coated
with a magnetic layer and a crash can occur if a small amount of dust,
a sudden movement of the computer or power surge causes the head to
bounce against the disk and damaging the magnetic coating. Modern
drives spin at extremely high speeds (between 4,200 and 15,000 rpm)
which means that when such a collision occurs, the damage incurred
can be quite serious.
Obviously, data corruption will occur at the onset of
a head crash as it will then become unreadable when the read-write
head attempts to access it. Furthermore, once a head crash has occurred,
this increases the probability of future head crashes, especially
if there is dust in the system, for instance which means the user
needs to take prompt action to rectify this in order to prevent further
head crashes and risk losing all data stored on the hard disk.
Logical errors
Logical errors also differ from the other failures mentioned as it
usually means that there is nothing actually physically wrong with
the disk in terms of architectural faults, instead there is a problem
with the information stored on it; there could be an invalid entry
in a file allocation table for instance. Some logical errors are not
too serious and can be tackled with various software tools, however
some logical errors can be of such severity that the use of software
‘repair’ tools will in fact exacerbate the problem and
make render the data unrecoverable.
Human error
In a sense it is rare that a hard disk failure could be caused by
a human alone. That is, of course providing that users take caution
in how they handle a computer. Combined with mechanical failure, human
error accounts for almost 75% of all incidents of data loss. All of
the previously mentioned hard disk failures could be caused by computer
misuse on the user’s part. Computers are very sensitive to changes
in temperature, dust and dirt etc entering the hard drive, electrical
power surges and knocks and bumps which may occur. Users should therefore
take extreme caution to prevent any of these circumstances from occurring
as much as they possibly can.
Other problems not caused by the hard disk
Aside from problems that may occur within the hard drive itself or
damage that may be incurred on the users’ part, other failures
can occur in other parts of the computer which can have a knock on
effect to the performance of the hard disk. These problems include
IDE cable malfunction, power connector problems and inappropriate
BIOS configuration. Each of these problems is explained below.
Although these problems identified will initially make
it seem like there is a problem with the hard drive and the user may
feel a great deal of frustration as the cannot gain access to the
data they require etc, because there is no actual problem with the
hard drive no data will actually be lost.
Go To: Part
Three - Methods of preventing failure and data corruption
