From startup to shutdown, Windows 7 is different from its
predecessors—and these differences go far beyond the gadgets and other
gizmos in Windows 7’s highly designed interface. If you want to truly
know how Windows 7 works and what makes it tick, you need to dig under the
hood.Windows Vista was the first truly hardware-independent version of
Windows, and Windows 7 continues this tradition. Unlike older releases of
Windows, Windows 7 doesn’t boot from a plain-text initialization file
(which was limited and prone to tampering). Instead, the operating system
uses the Windows Boot Manager and a more robust configuration system to
initialize and start the operating system. The Boot Manager is a key component of Windows 7’s extensive
boot environment.
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 preoperating 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. This means that the operating system can work with multiple
types of firmware interfaces without requiring the operating system to
be specifically written to work with these firmware interfaces. Rather
than updating the operating system each time a new firmware interface
is developed, the firmware interface developers can use the extensible boot environment to allow the
operating 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 7 to work with BIOS-based and EFI-based computers in
exactly the same way, and this is one of the primary reasons why Windows 7
achieves hardware independence.
The other secret ingredient for Windows 7’s hardware independence is
Windows Imaging Format (WIM). Microsoft distributes Windows
7 on media using WIM disk images. Here’s what you need to know about WIM right
now:
Windows Image (.wim) files
are used to deploy Windows 7. WIM uses compression and single-instance
storage to dramatically reduce the size of image files. Using
compression reduces the size of the image in much the same way as ZIP
compression reduces the size of files. Using single-instance storage
reduces the size of the image, because only one physical copy of a
file is stored for each instance of that file in the disk
image.
Because WIM is hardware-independent, Microsoft can use a single binary for each supported
architecture: one binary for 32-bit architectures and one binary for
64-bit architectures. If you work at a company that creates disk
images of various computer configurations, you can use this technology
to reduce the number of disk images you must maintain.
The final secret ingredient for Windows 7’s hardware independence is
modularization. Windows 7 uses modular component design so that each
component of the operating system is defined as a separate independent
unit or module. As modules can contain other modules, various major
features of the operating system can be grouped together and described
independently of other major features. Because modules are independent
from one another, you can swap modules in or out to customize the
operating system environment. Modularization has many benefits:
Thanks to modularization, you can more easily add features to the
operating system. Instead of having to go through a lengthy process
for adding or removing components as with earlier releases of Windows,
with Windows 7 you can easily turn features on or off. If you click
Start→Control Panel→Programs→“Turn Windows features on or off,” you
can quickly and easily select features to add or remove using the
Windows Features dialog box, shown in Figure 1.
Thanks to modularization, Windows 7 is language-independent.
Some languages are included with your version of Windows 7. Others you
need to obtain separately and install. You can add or remove language packs as easily as you
can Windows features. If you click Start→Control Panel→Change Display
Language under Clock, Language, and Region, you can quickly and easily
install and uninstall language packs. Click the Install/Uninstall
Languages button to launch the Install or Uninstall Display Languages Wizard,
shown in Figure 2, and
follow the prompts to add or remove language support. You’ll need to
insert the Windows 7 or language pack media when prompted.
