DDC Display data channel. The Plug and Play baseline for monitors. The communications channel between a monitor and the display adapter to which it is connected. This channel provides a method for the monitor to convey its identity to the display adapter.
device Any circuit that performs a specific function, such as a parallel port.
Device Bay An industry specification that defines a mechanism for both peripheral devices and system bays. Allows adding and upgrading PC peripheral devices without opening the chassis.
device ID A unique ASCII string for a device created by enumerators to identify a hardware device and used to cross-reference data about the device stored in the registry. Distinguishes each logical device and bus from all others on the system.
device node Also devnode. The basic data structure for a given device, built by the configuration manager. Device nodes are built into memory at system start-up for each device and enumerator. Each device node contains information about the device, such as currently assigned resources.
device object A kernel-mode–only object type used to represent a physical, logical, or virtual device whose driver has been loaded into the system.
devnode See device node.
digital A method of signal representation by a set of discrete numerical values, as opposed to a continuously fluctuating current or voltage. Compare with analog.
digital video A video signal represented by computer-readable binary numbers that describe a finite set of colors and luminance levels. Compare with analog video.
disk I/O controller Also hard disk controller. A special-purpose chip and circuitry that directs and controls reading from and writing to a computer’s disk drive.
DLL Dynamic link library. API routines that user-mode applications access through ordinary procedure calls. The code for the API routine is not included in the user’s executable image. Instead, the operating system automatically points the executable image to the DLL procedures at run time.
DMA Direct memory access. A method of transferring data between peripheral and host memory without processor intervention. The system board uses a DMA controller to handle a fixed number of channels, each of which can be used by only one device at a time.
DMI Desktop Management Interface. A framework created by the DMTF. DMTF specifications define industry-standard interfaces for instrumentation providers and management applications.
docking station The base computer unit into which a user can insert a portable computer, expanding it to a desktop equivalent. A typical docking station provides drive bays, expansion slots, all the ports on an equivalent desktop computer, and AC power.
driver Kernel-mode code used either to control or emulate a hardware device.
DSP Digital signal processor. An integrated circuit designed for high-speed data manipulations. Used in audio, communications, image manipulation, and other data-acquisition and data-control applications.
DTV Digital television. DTV standards allow standard resolution mode—with about twice the horizontal resolution of conventional analog broadcasts—as well as HDTV mode. Video uses MPEG-2 digital compression, and audio uses AC-3 (Digital Dolby) compression.
DVD Optical disk storage that encompasses audio, video, and computer data.