Understanding Windows PE
Environment (Windows PE) is a minimal version of Windows based on the
Windows Vista kernel (which is identical to the Windows Server 2008
kernel) that can be used for deployment and troubleshooting purposes.
Specifically, you can use Windows PE to:
Boot a bare-metal system to install Windows on it. (See Figure 4.)
Using Windows PE, you can boot the system, partition and format the
hard drives, and connect to a distribution share on the network to copy
down disk images and install Windows on the system in either attended or
unattended mode as desired.
a system on which Windows is already installed but not functioning
properly. Using Windows PE, you can launch Windows RE and run built-in
diagnostic and troubleshooting tools. You can also use Windows PE to
build a customized recovery solution for automatically recovering or
rebuilding computers running Windows.
Figure 4. The Windows PE command shell
In addition to these
uses, Windows PE also runs each time you install Windows Server 2008 on a
system. The graphic tools displayed during setup are actually running
within the Windows PE environment.
As can be seen from Figure A-4,
Windows PE presents you with a command-prompt interface from which you
can run various built-in tools useful for installation or
troubleshooting purposes. The following tools are available from the
Windows PE prompt.
Note: What’s the X drive?
The X drive in Windows
PE is a RAM disk (a writable volume in memory) used when Windows PE is
booted from read-only media such as a CD or DVD, a USB key, or a WDS
image. By default, Windows PE allocates 32 MB for this RAM disk, but you
can customize the size of the RAM drive by using the PEImg.exe utility.
Boot Configuration Data
This tool can be used to edit the boot configuration data (BCD) store,
which describes boot applications and boot application settings. The BCD
store in Windows Vista and Windows Server 2003 replaces the Boot.ini
used by earlier versions of Windows.
tool can be used to restore the boot sector on your computer by
updating the master boot code for hard-disk partitions to alternate
between BOOTMGR and NTLDR. The tool replaces the FixFAT and FixNTFS
tools used in earlier versions of Windows.
This tool can be used to manage disks, partitions, and volumes both
interactively from a command prompt and in automated mode, using
This tool can be used for adding out-of-box drivers to a booted Windows
PE image, using one or more driver .inf files as its inputs.
This tool can be used for creating an image (.iso) file of a customized
32-bit or 64-bit version of Windows PE, which you can then burn onto CD
media to create a bootable Windows PE CD.
This tool can be used to create or modify a Windows PE image, for
example, by importing a package, installing a driver, and so on.
This tool can be used to customize the default shell for Windows PE to
enable you to run your own shell application instead of the default
Windows PE command prompt.
Wpeinit.exe This tool is used to initialize Windows PE every time Windows PE boots.
More Info: Windows PE tools
For more information
about the Windows PE command-line tools, see the section titled “Windows
PE Tools Technical Reference” in the Windows Preinstallation
Environment (Windows PE) User’s Guide of the Windows AIK.
Windows PE was
originally designed as a way of initiating Windows Setup on bare-metal
systems without using MS-DOS network boot floppies. The first version of
Windows PE was based on the Windows XP kernel and was called Windows PE
1.0. When Windows Vista was released, a new version called Windows PE
2.0 was also released and was based on the newer Windows Vista kernel.
Note: Limitations of Windows PE
Windows PE has a number
of limitations, which means that it is not intended as an operating
system for daily use. For example, Windows PE automatically stops
working after 72 hours and reboots, and you can’t remove this
limitation. Also, any changes made to the Windows PE registry are lost
upon reboot (unless you make the changes when Windows PE is offline).
Additionally, Windows PE does not support the .NET Framework, the common
language runtime (CLR), or applications packaged as Windows Installer
(.msi) files. Finally, Windows PE supports only a subset of Win32 APIs,
which limits the applications that can be run on it.
many years, real-world administrators used MS-DOS boot floppies to boot
bare-metal hardware to perform unattended network installs of Windows
operating systems. There are a number of reasons why this practice is on
the way out. For example, MS-DOS has:
Minimal native networking support.
No support for the NTFS file system.
No support for 32-bit or 64-bit Windows device drivers.
Because of these
limitations—and the difficulty of even finding MS-DOS nowadays or people
who know how to customize it—Microsoft developed Windows PE as a new
tool for booting computers that have no installed operating system. By
way of contrast with MS-DOS boot floppies, Windows PE has:
Support for NTFS 5.x, including support for creating and managing dynamic volumes.
Support for TCP/IP networking, including a file-sharing client.
Support for 32-bit or 64-bit device drivers, depending on the version of Windows PE.
Support for booting from CD or DVD media, USB flash devices, and WDS used remotely.
To use Windows PE,
you typically use the tools included with the Windows AIK to create a
Windows PE build environment and convert it into an .iso file containing
the ready-to-run Windows PE operating system. If needed, you can also
customize your Windows PE build environment by adding additional tools
to it. Then, you use third-party CD-burning software to burn your .iso
file to CD media, and the result is a bootable Windows PE CD you can use
to launch the installation process on bare-metal hardware.