Defined in wdm.h:
typedef struct _DRIVER_OBJECT
{
CSHORT Type;
CSHORT Size;
PDEVICE_OBJECT DeviceObject; // link list maintained by IO manager
…
PDRIVER_EXTENSION DriverExtension; // AddDevice
…
PUNICODE_STRING HardwareDatabase; //registry key for the device
…
PDRIVER_STARTIO DriverStartIo; // function processes IO request
…
PDRIVER_DISPATCH MajorFunction; // table […]

(Notes from Oney’s book)
1. a driver is a collection of routines called by OS
DriverEntry, AddDevice
StartIo, AdapterControl, OnInterrupt, DpcForIsr, …
DispatchPnp, DispatchPower, DispatchWmi, DispatchRead, DispatchWrite
2. A Pnp device has an electronic signature that the system can detect
A legacy driver is added by end user through […]

responsible for creating functional device objects (FDO) or filter device objects (filter DO) for devices enumerated by the Plug and Play (PnP) manager.
1. IoCreateDevice to create a device object
2. [optional] IoRegisterDeviceInterface symbolic links to the device
3. Store the pointer to the device’s PDO in the device extension
4. Define flags in the device ext
5. Set flag […]

Called by I/O manager when the driver is loaded. Responsible for driver initialization. AddDevice routine responsible for device initialization.
1. Supply entry points for the driver’s standard routines
2. Create and/or initialize various driver-wide objects, types, or resources the driver uses
3. Free any memory that it allocated and is no longer required
PcInitializeAdapterDriver binds an adapter driver to […]

A. The IPortWaveCyclic interface is the WaveCyclic port driver’s primary interface. IPortWaveCyclic inherits from the IPort interface. The PortCls system driver implements this interface and exposes it to the adapter driver that implements the IMiniportWaveCyclic object.
An adapter driver creates an IPortWaveCyclic object by calling PcNewPort.
An adapter driver forms a miniport/port driver pair by […]

A. Custom audio driver
1. custom audio-adapter driver for use with the PortCls system driver (portcls.sys)
2. custom minidriver for use with the AVStream class system driver (ks.sys)
PortCls contains a built-in audio-driver infrastructure and generic functions of a particular
type of wave, midi, or mixer device. Vendor needs to develop miniport drivers that works with
selected port drivers.
B. Choosing […]

Kernel streaming (KS) services support kernel-mode processing of data streams for audio and for other types of continuous media. Conceptually, a stream undergoes processing as it flows along a data path containing some number of processing nodes.
A set of related nodes is grouped together to form a KS filter, which represents a more-or-less independent […]

All WDM drivers must:
Include wdm.h, not ntddk.h. (Note that 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 as described in WDM Device Objects and Device Stacks.
Support Plug and Play.
Support power management.
Support […]

1. application
The application handles requests from users and other applications, and calls either the Win32 API or a routine that is exposed by the user-mode client driver.
2. A user-mode client driver
handles requests from applications or from the Win32 API. For requests that require kernel-mode services, the user-mode client driver calls the Win32 API, which […]