Windows® System Image Manager (Windows SIM) creates an XML-based answer file required to complete unattended setup. Windows SIM also creates a catalog (.clg) file to keep track of packages and settings, which requires periodic updates. A file known as a "configuration set" can be created and copied to a removable media as a portable version of the optional distribution share folders.
The following diagram shows how Windows SIM works.
Windows System Image Manager Architecture
Windows SIM uses the Component Platform Interface (CPI API) to create an unattended answer file. Windows SIM initially uses the CPI API to mount a Windows image. The components and settings in a specific Windows image are used to create a catalog file. This catalog file is used in Windows SIM to create answer files. For more information, see Understanding Windows Image Files and Catalog Files.
An optional set of folders, called a "distribution share," can be added to store files that you use to further customize your Windows installation. For more information, see Understanding Distribution Shares and Configuration Sets.
Windows SIM can create a smaller, more portable version of a distribution share called a configuration set. Configuration sets enable users to use smaller versions of a distribution share. These smaller files can be more easily managed.
You can also use the CPI API to create your own customized applications that can automate the creation and management of unattended Windows Setup answer files. For more information, see the Component Platform Interface (CPI) Reference.