D

DAC (Digital-to-Analog Converter)

A device used to convert digital information to analog signals. A DAC is typically used by a modem to prepare information for analog phone line transmission.

DC (Direct Current)

DC is the unidirectional movement or flow of electrons. DC is necessary for most electronic computer components.

Desktop

The Windows screen that opens when the computer is booted. Contains the Start menu, the Task Bar, the System Tray, and all the icons.

desktop computer

Originally meant to mean a computer in a horizontal case, it has come to mean any personal computer that is not portable.

developer

Company or individual who makes software.

DHCP (Dynamic Host Configuration Protocol)

A protocol used to dynamically assign IP addresses to computer systems in a TCP/IP network. DCHP eases administrative overhead by reducing the need to assign individual static IP addresses.

DHTML (Dynamic Hypertext Markup Language)

A new form of HTML programming code that allows developers to create more-interactive or responsive Web pages for users.

dialog box

A rectangular window containing configuration controls.

DIMM (Dual Inline Memory Module)

A 64-bit data path memory module. In Pentium computers, one DIMM can be installed in a memory bank.

DIN AT

The wide 5-pin plug/socket used to connect a keyboard to an AT motherboard.

DIP switch

A tiny switch used for configuring some hardware devices, especially older devices.

directory

See folder.

display

See monitor.

DMA (Direct Memory Access)

A technique used by computer devices to access and move data in and out of memory without interrupting the CPU. It is used by certain hardware devices such as hard drives, floppy drives, and sound cards to interact directly with system memory rather than burden the processor. Enable or disable DMA in a device’s system property page.

DNS (Domain Name System)

An Internet service that translates fully qualified domain names to computer IP addresses.

dongle

A small cable with a telephone or Ethernet jack on one end, the other end of which plugs into a PC Card network adapter or modem. Dongles are usually fragile, especially at the plug that plugs into the PC Card. Many newer PC Cards have built-in jacks, making dongles unnecessary. See PC Card.

DOS (Disk Operating System)

A 16-bit operating system developed by Microsoft that does not support true multitasking capabilities.

dpi (Dots Per Inch)

A measurement of image resolution. The number of dots per horizontal inch is used to calculate the dpi that a device, such as a printer, is able to produce.

DRAM (Dynamic Random Access Memory)

A popular type of memory used to store information in a computer system. DRAM chips must be electronically refreshed continuously to hold their data.

drive cage

An assembly in a computer that holds disk drives.

driver, device

A piece of software that allows the OS and programs to communicate with a hardware device. Hardware devices can’t work without some type of driver, even if Windows’ Device Manager indicates that no driver is necessary.

driver, generic

A device driver that is designed to work with most or all devices in a general category of hardware devices, such as a video adapter or modem. Generic drivers usually don’t allow all of a device’s features to work. An example of a generic driver is the video driver that provides minimum video resolution and color depth when a computer first starts to boot.

DSL (Digital Subscriber Line)

A popular high-speed technology that uses phone lines for Internet connectivity. The two most widely used forms of DSL are ADSL (Asymmetric Digital Subscriber Line) and SDSL (Symmetric Digital Subscriber Line).

dual-boot

A computer with two separate OSs that are selectable at the time of boot.

DVD (Digital Versatile Disk or Digital Video Disk)

A type of CD technology developed for full-length motion pictures that can hold 4.7GB to 17GB of information.

DVI

Digital Video Interface. The standard interface for digital video on PCs. Digital monitors and video adapters have DVI connectors.

DVO

The digital video header connector on a motherboard for connection of a digital video adapter.