Introduction to WDM

Important

This section contains guidance on WDM drivers, which is no longer the recommended driver model. For guidance on choosing a driver model, see Choosing a driver model.

The Windows Driver Model (WDM) was introduced to enable driver developers to write device drivers that are source-code compatible across all Microsoft Windows operating systems. Kernel-mode drivers that follow WDM rules are called WDM drivers.

All WDM drivers must do the following tasks:

• Include Wdm.h, not Ntddk.h. (Wdm.h is a subset of Ntddk.h.)

• Be designed as a bus driver, a function driver, or a filter driver, as described in Types of WDM Drivers.

• Create device objects.

• Support Plug and Play (PnP).

• Support power management.

• Support Windows Management Instrumentation (WMI).

Should You Write a WDM Driver?

If you're writing a new driver, consider using the Kernel-Mode Driver Framework (KMDF). KMDF provides interfaces that are simpler to use than WDM interfaces.

Don't write a WDM driver if the driver is part of a stack of non-WDM drivers. Read the documentation for device type-specific Microsoft-supplied drivers to determine how new drivers must interface with Microsoft-supplied drivers. For more information, see Device and Driver Technologies.