Working with Windows Vista
extensive boot environment. You’ll learn all about the Boot Manager and the boot
environment in Chapter 23; here’s what you need to know right now:
• The boot environment dramatically changes the way the operating system starts.
Microsoft created the boot environment to resolve several prickly problems
related to boot integrity, operating system integrity, and firmware abstraction.
• The boot environment is loaded prior to the operating system, making it a pre-
operating system environment. As such, you can use the boot environment to
validate the integrity of the startup process and the operating system itself before
actually starting the operating system.
• The boot environment is created as an extensible abstraction layer that allows
the operating system to work with multiple types of firmware interfaces without
requiring the operating system to be specifically written to work with these firm-
ware interfaces. Rather than updating the operating system each time a new
firmware interface is developed, the firmware interface developers can use the
standard programming interfaces of the boot environment to allow the operat-
ing system to communicate as necessary through the firmware interfaces.
Currently, Basic Input Output System (BIOS) and Extensible Firmware Interface
(EFI) are the two prevalent firmware interfaces for computers. Firmware interface
abstraction makes it possible for Windows Vista to work with BIOS-based and EFI-
based computers in exactly the same way, and this is one of the primary reasons why
Windows Vista achieves hardware independence.
Figure 1-4. Changing your product key