Windows Images enable an easy and straight forward Windows 7 Desktop Deployment throughout the organisation with reduced efforts and streamlined approach. Windows Images come in two different formats. One is the Windows Imaging Format (.wim) format and the other is Virtual Hard Disk (.vhd) format.
The .wim image can only store a single volume of a hard disk at any given time. But, a single .wim file is capable of storing multiple images through single instancing and thus reduces the amount of storage that is required. Single instancing is particularly helpful in cases where different Windows 7 images have been built with applications for particular departments. These images with different set of applications can be put into in the same .wim file and single instancing makes sure that the same file is not copied twice i.e. the core operating system files. Another feature with .wim files is that they can be serviced offline which is particularly useful for loading operating system updates by mounting the image, making the necessary changes and then un-mounting it for use on target systems. The .vhd format on the other hand is capable of storing the image of an entire hard drive. While deciding the strategy of deployment for Windows 7, the image formats may be decided.
Windows 7 Image Types
The Windows 7 images fall into a three different types. The first being the Thin image which only contains the Operating System. In case other applications need to be deployed, separate images need to be built which will have the applications. A thick image would contain the operating system along with the applications that need to be deployed. Thick images are particularly hard to work with if changes need to be made to the image at a later stage. There are also hybrid images that would have both operating system and up to some extent company/organisation approved applications.
Images can be created using ImageX or Windows Deployment Services (WDS) or Microsoft Deployment Toolkit (MDT) 2010 Update 1. When ImageX is used to create an image the operations system, drivers, applications and packages need to be installed manually. MDT 2010 Update 1 allows automation of the process of deployment of OS, drivers, applications and packages to a brand new system. The MDT also comes with a Sysprep and it enables to capture the task sequence as well. With WDS you may use the built in WDSCapture utility to capture images of the newly built system. Tweaking of the setting may be needed while using WDS.
Image Creation Steps
Creation of an image involves the following broad steps: installation of the Operating System, applications, drivers and patches. Following that the newly installed system needs to be ‘Syspreped’. The important thing to keep in mind here is to use the right Sysprep otherwise it might create issues which would lead to an incorrect image creation and subsequently if deployed, deployment of the wrong image across the entire organisation. Following the Sysprep it is considered a best practice to shut down the system and then booting the system with WinPE. Through WinPE, ImageX is the default capture program and it would create the .wim file. Alternatively .vhd files may also be created using the disk management tools available in Windows 7.