D

Darwin

Core operating system in Mac OS X. It is an open-source operating system (XNU) built on the Mach 3.0 kernel.

data fork

See [file fork]

DAT files

Virus definition files used by virus protection software. They contain information about virus threats and their cures, and must be kept up-to-date.

Desktop folder

User-specific location for items on the user's desktop. Found in the file system at ~/Users/Username/Desktop.

DHCP (Dynamic Host Configuration Protocol)

A method for acquiring an IP address in which a range of unique addresses are assigned to computers.

directory (file system)

See [folder]

directory (service)

A database that keeps track of the resources available to the users of that database. Common directories are LDAP, Open Directory, and Active Directory.

discovery

The method by which an application finds computers and services on a network. Bonjour is a method of automatic service discovery used by many programs, such as the Finder and iChat. AppleTalk is still used in some environments for printer discovery.

disk image

In Mac OS X, a disk image is a file that works like a drive volume. When opened, it mounts in /Volumes and appears on the desktop. Disk images can be compressed, encrypted, and resized.

DNS (Domain Name System)

DNS servers are host machines that can translate domain names into IP addresses.

Dock

Tool in the Mac OS X Finder that allows users to quickly access and open applications, documents, and other frequently used items.

driver

A program that enables a user to access and interact with a hardware device.

DSL (Digital Subscriber Line)

A high-speed connection to an Internet service provider using the same wires as a regular telephone line.