Windows Deployment Platform Components - Windows PE

Prior to Windows PE, organizations often had to use MS-DOS boot floppies to start destination computers and then start Windows Setup from a network share or other distribution media. MS-DOS boot floppies had numerous limitations, however, including that they offered no support for the NTFS file system and no native networking support. In addition, they needed to locate 16-bit device drivers that worked in MS-DOS.

Now Windows PE 3.0 provides a minimal Win32 or Win64 operating system with limited services—built on the Windows 7 kernel—that you use to prepare a computer for Windows 7 installation, copy images to and from a network file server, and start Windows Setup. Windows PE 3.0 is a stand-alone preinstallation environment and an integral component of other setup and recovery technologies, such as Windows Setup, Windows Deployment Services, System Center Configuration Manager 2007 R2, and MDT 2010. Unlike earlier versions of Windows PE, which were available only as a Software Assurance (SA) benefit, Windows PE 3.0 is now publicly available in the Windows AIK 2.0.

Windows PE provides the following features and capabilities:

• Native support for NTFS 5.x file system, including dynamic volume creation and management

• Native support for Transmission Control Protocol/Internet Protocol (TCP/IP) networking and file sharing (client only)

• Native support for 32-bit (or 64-bit) Windows device drivers

• Native support for a subset of the Win32 Application Programming Interface (API); optional support for Windows Management Instrumentation (WMI) and Windows Script Host (WSH)

•Can be started from multiple media, including CD, DVD, USB Flash drive (UFD), and
Windows Deployment Services

Windows PE runs every time you install Windows 7, whether you install the operating system by booting the computer with the Windows 7 DVD or deploying Windows 7 from Windows Deployment Services. The graphical tools that collect configuration information during the windowsPE configuration pass run within Windows PE. In addition, you can customize and extend Windows PE to meet specific deployment needs. For example, MDT 2010 customizes Windows PE for LTI by adding device drivers, deployment scripts, and so on.

For Windows 7, Windows PE 3.0 includes improvements that make it easier to customize.
First, the functionality of PEImg is now included in DISM, providing a single tool you can use to service images whether they’re Windows 7 images or Windows PE images. Second, Windows PE 3.0 uses a new package model. Instead of the base image including all the feature packages from which you remove the disabled features, the base image doesn’t include these feature packages, and you add the features that you want to include in the image.

Because Windows PE is only a subset of Windows 7, it has limitations. For example,
Windows PE automatically stops running the shell and reboots after 72 hours of continuous use to prevent piracy. You cannot configure Windows PE as a file server, terminal server, or embedded operating system. Moreover, mapped driver letters and changes to the registry are not persistent between sessions. For more information about the limitations of Windows PE, see the Windows Preinstallation Environment User’s Guide in the Windows AIK 2.0.

Source of Information : Windows 7 Resource Kit 2009 Microsoft Press