Hardware Reference
In-Depth Information
end user. Most hard drive manufacturers make initialization and test programs available, which are
the modern substitute for low-level format programs. Although the initialization programs do not
technically recreate the sector header or trailer marks, they do rewrite the data portion of all sectors
as well as manage defects, including the ability to reassign spare sectors to replace defective sectors.
Normally, the only time you run an initialization program is when you are attempting to repair a
format that has become damaged (parts of the disk become unreadable) or in some cases when you
want to wipe away all data on the drive.
Caution
In Windows XP and earlier, a high-level format does not overwrite the data area of the disk.
Instead, it only rewrites the table of contents, leaving the data area sectors intact. This is true
whether you use the “quick” or full-format options. As such, unerase utilities such as Recuva
(
www.piriform.com/recuva
) can recover files from a formatted drive because the data sectors
are not actually overwritten. However, this behavior was changed for Windows Vista and
later, such that the standard full format does overwrite all the sector data with zeros, thereby
making the recovery of any previous files or data impossible. You can prevent the overwriting
of all data sectors in Vista and later by using the “quick” format option. See the Microsoft
KB941961 article at
http://support.microsoft.com
for more information.
Basic HDD Components
Many types of HDDs are on the market, but nearly all share the same basic physical components.
Some differences might exist in the implementation of these components (and in the quality of the
materials used to make them), but the operational characteristics of most drives are similar. The basic
components of a typical HDD are as follows (see
Figure 9.10
):
• Disk platters
• Read/write heads
• Head actuator mechanism
• Spindle motor (inside platter hub)
• Logic board (controller or Printed Circuit Board)
• Cables and connectors
• Configuration items (such as jumpers or switches)
