Writing WDM Drivers

This section discusses the Microsoft Windows Driver Model (WDM) architecture. This architecture started in Windows 2000 as an enhancement to previous Windows NT device drivers.

Note  Drivers for versions of Windows NT-based operating systems before Windows 2000 are not supported, and you should update these drivers. The WDM architecture does not support drivers for non-Windows NT-based operating systems (such as Windows 98), and you should rewrite such drivers.

This section is divided into three parts:

  • Windows Driver Model describes the Windows Driver Model (WDM), including types of WDM drivers, device configuration, and WDM versioning.

  • Device Objects and Device Stacks describes device objects and device stacks. The section includes information about physical device objects (PDOs), functional device objects (FDOs), and filter device objects (filter DOs). Drivers are often built from a set of device objects that work together. This set of device objects is called a stack. Stacks can help you understand the flow of information to and from a driver and how different parts of the driver communicate internally.

  • Kernel-Mode Driver Components describes which routines you must implement to have a functional driver and which routines are optional.

    A device driver is a set of software code that must integrate into the operating system. To complete this integration, you must write a set of handler routines in your driver that process calls from the operating system. These routines can be simple function calls, but many of them implement the processing of I/O request packets (IRPs), which facilitate communication between drivers and the operating system.

Note  WDM drivers can also use the Windows Driver Frameworks (WDF) library to make some parts of a device driver easier to write. Specifically, kernel-mode drivers can use the Kernel-Mode Driver Framework (KMDF), which is part of WDF. For more information about KMDF for kernel-mode drivers, see Kernel-Mode Driver Framework Overview. Note that KMDF does not replace WDM. You must still understand many parts of WDM to write a KMDF driver.