Hardware Reference
In-Depth Information
Figure 5.6. IBM/Lenovo implementation of the Phoenix BIOS preboot environment.
A graphical preboot environment is especially useful for product recovery. For example, most of the
larger system OEMs do a lot more than just install Windows on a system before they deliver it. After
installing Windows, they install all the service packs and updates available at the time, as well as all
the updated drivers unique to their systems. Then they add customizations, such as special wallpapers
or interface customizations, support contact information, online system documentation, and custom
utilities designed to make their systems easier to use. Finally, they install applications such as DVD
players, Office applications or other productivity software, and more.
This OEM customization represents a lot of work if a user were to have to duplicate this from
scratch, so most manufacturers like to include the ability to easily recover the system to the factory-
delivered contents, including the OS, drivers, applications, and custom configuration. This was
originally provided via several CDs or DVDs, which could be lost or damaged by the user, were
sometimes problematic to use, and cost money to produce and deliver with the system. By using a
BIOS with a preboot environment, an OEM can instead deliver the contents of the recovery CDs
directly on the hard disk and make it accessible via the preboot menu in the BIOS.
Originally, this was done using a hidden partition, which unfortunately could easily be damaged or
overwritten by partitioning software or other utilities. In many newer systems, the contents of the
recovery disks are instead preinstalled in the HPA, which is accessible via Protected Area Run Time
Interface Extension Services (PARTIES), a standard supported on all ATA-4 or newer drives.
HPA/PARTIES works by using the ATA
SET MAX ADDRESS
command to essentially make the
drive appear to the system as a slightly smaller drive. Most manufacturers use the last 3GB of the
drive for the HPA. Anything from the new max address (the newly reported end of the drive) to the
true end of the drive is considered the HPA and is accessible only using PARTIES commands.
Figure
