Whats WDM?
WDM, formerly known as the “Windows Driver Model”, and now known as the “Win32 Driver Model” (a confusing name, since it does not use Win32 APIs), essentially is the NT driver model but with a few things changed, a few things left out, and a large number of new IRP types and callable routines provided by the OS. Most of the new stuff is there to to support to support new (to NT) functionality such as plug and play and power management. It is implemented (with some differences) on both Windows 2000 and Windows 98.
