• Windows Driver Foundation (WDF) architecture
• Replaces the older Windows Driver Model (WDM)
• Defines how device driver software operates
• With WDM, drivers spend much of their time interacting with the OS instead of the hardware
• Driver software has access to the computer's hardware at two distinct levels: Kernel and user mode.
• Kernel mode drivers
• Have direct access to all hardware and memory
• User mode drivers
• Have restricted access and must pass a request to the operating system
• User mode driver architecture is defined under WDF
• In addition to kernel mode drivers
• If the user mode driver fails
• It can be restarted without causing the core, or kernel, of the operating system to crash with it
• WDF drivers support distributed computing

For more information about the Windows Driver Foundation (WDF) architecture, visit: http://www.microsoft.com/whdc/driver/wdf/default.mspx