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System Image Facts

A system image is a single file containing all the contents of the Windows 7 operating system installation and any additional files on a computer's hard drive. System administrators typically use system images to centrally deploy Windows 7 to computers throughout large, enterprise environments. A Windows 7 system image is stored as a Windows Image (WIM) file. A WIM:

  • Contains all of the necessary installation files.
  • Is file-based (not sector-based as in ISO files).
  • Has the .wim extension.
  • Can contain multiple disk images.
  • Uses a single-instance storage and references in a file system tree to save space and imaging time.
  • Is hardware independent.
  • Can be spanned into multiple parts, each with a .swm extension.
  • Can be mounted as a new volume under Windows with a drive letter for extraction or content updates.

The Windows Automated Installation Kit (Windows AIK) includes the following tools to help in system image preparation, maintenance, and deployment:

  • Windows Preinstallation Environment (Windows PE or WinPE) is a thin version of Windows. WinPE is used to:
    • Start a limited operating system during installation.
    • Boot to a network drive to load an operating system and configure the network connection prior to loading the operating system located on the network.
  • Windows System Image Manager (Windows SIM) creates and manages answer files that are used for automated installations. When you create an answer file, responses to the setup questions are saved in an XML file.
  • System Preparation Tool (Sysprep) prepares a Windows installation for imaging by removing machine-specific information.
  • ImageX is a command line tool that creates an image file for Windows 7 deployment from a reference (source) computer.
  • Deployment Image Servicing and Management (DISM) applies updates, drivers, and language packs to a Windows image.
  • Oscdimg creates ISO images for the Windows PE boot disc.

Preparing a system image requires the following types of computers:

  • The reference computer holds the operating system instance that you want to copy.
  • The technician computer is a computer that uses the Windows AIK tools which are necessary to create and manage system images.

The following are general steps when working with the two types of computers:

  1. On the technician computer, use Windows SIM to build, validate, and save an answer file to automate the installation of Windows 7. Note: Creating an answer file is not necessary, but recommended by Microsoft documentation.
  2. On the reference computer, install Windows 7 by way of the installation source (e.g., DVD, flash drive, or network share) and answer file (optional).
  3. On the reference computer, use the Sysprep utility to remove machine-specific information.
  4. On the technician computer, create a Windows PE boot disc or USB flash drive which includes the ImageX tool.
  5. On the reference computer, boot into Windows PE and use ImageX to capture the Windows installation onto a network share.