I blogged on DISM in the past, but I continue to be impressed with this Microsoft utility’s capabilities. DISM is included with the Windows Automated Installation Kit for Windows 7 (WAIK), which can be downloaded from Microsoft at: http://www.microsoft.com/downloads/en/details.aspx?familyid=696DD665-9F76-4177-A811-39C26D3B3B34&displaylang=en
DISM can interact with an installation of Windows 7 that is stored in either a Windows Image file (WIM) or a Virtual Hard Drive file (VHD). A WIM file is Microsoft’s own image file similar to a Ghost image file (GHO). Starting with Windows Vista and Server 2008 and now Windows 7, all Windows operating systems are distributed using WIM image files. The Windows installation DVD has a WIM file called Install.wim that contains all of the files needed to install Windows. When Windows is installed from the DVD, the Install.wim expands and is applied to the computer’s hard drive. No more I386 folder.
Windows 7 and Server 2008 R2 can be installed into a VHD file instead of a conventional formatted partition. This makes the installation more portable as the entire internal file structure of Windows is contained within a single VHD. Native boot installations of Windows aren’t Virtual Machines running on Hyper-V or VMware, they are physical installations into a VHD.
Many administrators would like to take the standard Install.wim on the Windows installation DVD and add applications and other customizations. The tools in the WAIK are used to create a reference installation of Windows that’s modified by adding software applications such as Office. Sysprep is run on the reference installation to strip out the security identifiers, computer name, and other identifiers to make Windows suitable for duplication. When Sysprep has completed, the computer is shut down and then booted with a special version of Windows PE that comes with the WAIK. From Windows PE a tool called ImageX is run to capture the shut-down, Sysprepped installation of Windows 7 as a new custom WIM image file. This custom WIM can then be installed on many computers using different technologies including SCCM operation system deployment, the Microsoft Deployment Toolkit and the Windows Deployment Service (WDS) found on Windows Server 2008.
DISM allows administrators to make updates to Windows 7 even when it is an offline WIM file. DISM can mount a Windows 7 image and add security updates, out-of-box drivers and enable or disable features.
Window 7 can even be upgraded from one edition to another offline by using the Dism /Set-Edition parameter. If, for example, you wish to upgrade an image of Windows 7 Home Premium to Ultimate Editon, type the following: Dism /Image:C:\test\offline /Set-Edition:Ultimate
Check out the DISM command line servicing options at: