Desktop Window Manager
Desktop Window Manager, or DWM, is the window manager in Windows Vista that provides the graphical backend for Windows Aero and Flip3D.
A compositing window manager like DWM handles drawing to the screen for all applications. All of the running applications write to DWM, which then creates a composite image and writes that to the actual display.
This allows DWM to handle things like transparency, or the live thumbnail images that you see in Alt+Tab, Flip3D or even the taskbar preview thumbnails.
DWM uses DirectX to write directly to the graphics card, as well as use the special features of a graphics card such as 3D accelleration, saving your CPU from having to do the processing.
Path to file: C:\Windows\System32\svchost.exe -k LocalSystemNetworkRestricted
Startup Type: Automatic Todo: Break into two articles, one for service and one for the window manager.
Vista is not the only operating system with this type of functionality. Both Mac OS X and Linux have a similar architecture.