The compression of data (text, sound, or graphics) in order to reduce the size of a file. The larger the file, the more time it takes to open or transfer it. (See compression.)
DejaNews
A newsgroups search engine that conducts searches within Usenet. (See search engine.)
Device
A hardware or peripherial component (printer, modem, mouse,etc.) that can receive or send information. (See device driver, modem.)
Device driver
A program that supplies an operating system with all necessary information for working with a specific device. (See operating system, device.)
Dial up
Calling another computer via modem.
(See modem.)
Dialer program
Special software that dials to the Internet Service Provider and makes the connection for the user. (See ISP, PPP.)
DNS-Domain Name Server
The Domain Name System for translating computer names (such as "geo.co.il") into numeric Internet addresses (such as192.112.12.20") and vice versa. DNS allows you to use the Internet without remembering long lists of numbers.
(See IP number.)
Domain name
One of the components of an Internet address. The domain name represents the kind of organization the address belongs to, for example: gov-governmental, ac-academic, etc. (See address, URL.)
Downloading
Connecting to another computer and placing one of its files on your computer. (See FTP.)
Duplex
A communication channel that simultaneously transfers data in two directions. Thus, when you speak on Iphone you use a duplex channel, allowing both speakers to talk at once. If a regular channel was used, each speaker would have to wait until the other finished talking prior to responding. (See half duplex.)
