![]() ![]() The function driver is generally the only driver that accesses the device’s hardware. The bus driver is responsible for detecting bus membership changes (device addition or removal), assisting the PnP manager in enumerating the devices on the bus, accessing bus-specific configuration registers, and, in some cases, controlling power to devices on the bus. In WDM, no one driver is responsible for controlling all aspects of a particular device. For example, a keyboard capture utility could be implemented with a keyboard filter driver that layers above the keyboard function driver. In general, it’s the driver with the most knowledge about the operation of the device.įilter drivers logically layer either above or below function drivers (these are called function filters) or above the bus driver (these are called bus filters), augmenting or changing the behavior of a device or another driver. The function driver is the driver that exports the operational interface of the device to the operating system. Bus drivers present devices to function drivers via the PnP manager. A bus driver is responsible for detecting and informing the PnP manager of devices attached to the bus it controls as well as managing the power setting of the bus.įunction drivers manage a particular type of device. Examples of buses include PCMCIA, PCI, USB, and IEEE 1394. There are three types of WDM drivers:īus drivers manage a logical or physical bus. WDM includes support for Windows power management, Plug and Play, and WMI, and most Plug and Play drivers adhere to WDM. WDM drivers are device drivers that adhere to the Windows Driver Model (WDM). ![]() Within the category of kernel-mode drivers are further classifications based on the driver model that the driver adheres to and its role in servicing device requests. Process Monitor’s driver, described in Chapter 4 in Part 1, is also an example. Examples include network API and protocol drivers. They do not typically integrate with the PnP or power managers because they typically do not manage an actual piece of hardware. Non–Plug and Play drivers, which also include kernel extensions, are drivers or modules that extend the functionality of the system. They include drivers for mass storage devices, video adapters, input devices, and network adapters. Plug and Play drivers work with hardware and integrate with the Windows power manager and PnP manager. There are many types of kernel-mode drivers, which can be divided into the following basic categories:įile system drivers accept I/O requests to files and satisfy the requests by issuing their own, more explicit, requests to mass storage or network device drivers. In this chapter, the focus is on kernel-mode device drivers. See the User-Mode Driver Framework (UMDF) section later in this chapter for more information. They communicate to the kernel-mode UMDF support library through ALPC. User-Mode Driver Framework (UMDF) drivers are hardware device drivers that run in user mode. These commands are then typically forwarded to a kernel-mode port driver such as the universal serial bus (USB) printer port driver (Usbprint.sys). Windows subsystem printer drivers translate device-independent graphics requests to printer-specific commands. Windows supports a couple of types of user-mode drivers: The broadest classification of a driver is whether it is a user-mode or kernel-mode driver. Even within a type of device driver, programming environments can differ, depending on the specific type of device for which a driver is intended. Windows supports a wide range of device driver types and programming environments. In this section, we’ll look at the types of device drivers Windows supports as well as the internal structure of a device driver. To integrate with the I/O manager and other I/O system components, a device driver must conform to implementation guidelines specific to the type of device it manages and the role it plays in managing the device. ![]()
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