Understanding Component-Based Servicing

Prior to Windows Vista, if you wanted to install optional components, Windows Updates or driver files on your system, the process was fairly simple.  In Windows Vista, the new componentization architecture, known as Component-Based Servicing (CBS) changes the way that these components are installed.  The CBS architecture is far more robust and secure than the […]

Prior to Windows Vista, if you wanted to install optional components, Windows Updates or driver files on your system, the process was fairly simple.  In Windows Vista, the new componentization architecture, known as Component-Based Servicing (CBS) changes the way that these components are installed.  The CBS architecture is far more robust and secure than the installers in previous operating systems.  Users benefit from a more complete and controlled installation process that allows updates, drivers and optional components to be added while simultaneously mitigating against instability issues caused by improper or partial installation.  CBS allows components and features from IIS to Windows Media Player to be packaged as small modules that encompass the full functionality of the component.  In other words, each module contains all of the files, registry settings, and methods required for a full installation or removal of the component it contains.  The Core componentization services include the following:

  • CBS (Component Based Servicing) - Also known as the trusted installer (TI.EXE), which works at the package / update level
  • CSI (Component Servicing Infrastructure) - Works at the deployment/component level
  • CMI (Component Management Infrastructure) - Handles the advanced installer level
  • DMI (Driver Management Infrastructure)
  • SMI (Systems Management Infrastructure)

The Servicing Stack in Windows Vista consists of three levels:

  • At the top of the stack are the top level clients, such as Windows Update, Programs and Features, and MSI, which deliver packages to a system.  The top-level clients are also responsible for control of user input and collection of user preferences during the servicing process.
  • In the middle of the servicing stack is the Trusted Installer, CBS.  The top-level clients pass downloaded packages to CBS, which evaluates each individually to determine if they are applicable to the system.  For applicable updates, CBS provides the components to CSI, generates appropriate installation events, and registers packages with Programs and Features if needed.  Finally, CBS exposes the interfaces to enumerate and inventory the updates.
  • At the bottom of the servicing stack is CSI, which uses the Kernel Transaction Manager (KTM) to do its work.

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Windows Vista, Troubleshooting, Architecture, Knowledgebase