Internet Dictionary
Click on a letter to see the relevant terms: A B C D E F G H I J K L M N O P Q R S T U V W Z

Data Numbers, letters, facts, and anything else that can be processed by a computer for a specific purpose. For instance, number crunching is very common. You can input all the numbers (data) needed to solve a problem and let the computer do the rest. Or you can use a word processor to create a text document (the alphabet letters are the data). Or you can use a paint program to create a picture. The pixel locations and colors are the data. The data is only half the story. You need a program to tell the computer how to process the data.

Dialup This means you have to dial an access phone number for your computer to communicate with the Internet. With dialup, you use either a data modem with a typical speed limit of 28.8 Kbps or an ISDN modem with a speed limit of 128 Kbps. Like most of the people, you are probably using dialup to connect the Internet. Your ISP will assign your computer an IP address at the time when it is connected to the Internet.

Digital signal A signal that changes discontinuously or in abrupt steps during the cycle. A square wave is an example of a digital signal. On the other hand, a sine wave is an example of an analog signal, one that changes continuously or gradually during the cycle.

Direct connection A direct connection, also called dedicated access, means your computer is connected to the Internet 24 hours a day through a high-speed connection, either T1 or T3. Typically, a LAN is connected to the Internet through a direct connection.

DNS An abbreviation for domain name server. This is a computer that converts a domain name to an IP address. For instance, the domain name for this web site is malvino.com. To access this web site, you entered a URL of http://www.malvino.com. The malvino.com part of the URL was sent to a DNS where it was converted to an IP address of 207.201.155.6. The foregoing numbers are the IP address of malvino.com. Every other web site has a different IP address. The TCP/IP packet from your computer was then sent to my web site. It's like the ordinary postal system, only done at speed of light. Once your packet arrived at my web site, a reply was sent back to your computer, which had already been assigned a temporary IP address when you dialed into your ISP.

Domain Name The domain name is the name given to a web site using human language. For instance, the domain name for this web site is malvino.com. The domain name is closely related to the IP address. The IP address is the domain name converted to numbers that a computer can understand. The IP address for this web site is 207.201.155.6. To reach this web site, your computer sent the domain name of "malvino.com" to a DNS, which then converted it to an IP address of "207.201.155.6".

Download To transmit a file from a higher level to a lower level, like from a server to a client.

Dumb terminal The computer you are using has more hardware and software than necessary for Internet communication. For instance, the hard disk is unnecessary if all you're trying to do is download pages since these pages can go directly into the RAM. If all the unnecessary hardware and software were removed from your computer, all that would be left would be a dumb terminal. It could download and run programs using the whole Internet as kind of distributed hard drive for your computer. Larry Ellison of Oracle Corporation believes that dumb terminals will replace most computers that currently sit on desktops. Instead of using programs and data on your hard disk, you will be using programs and data on some ISP's server. Will it happen? Definitely. When user bandwidth is 10 Mbps and server response time is the same as your current hard drive. Everything out there on every server in the world will become your virtual hard drive. Optimists think user bandwidths of 10 Mbps are only a few years away. Pessimists insist it will take more than 10 years to eliminate all bottlenecks, rewire slow parts of the Internet with fiber optics, etc.

Dynamic routing When information is sent from one part of the Internet to another, it can be sent along many different routes. In other words, there are many redundant paths a signal can follow getting from point A to point B. This redundancy was deliberately designed into the system because Arpanet, the forefather of the Internet, was designed to withstand nuclear attack. The choice of many different paths allows for dynamic routing, which means signals can be sent around temporarily broken or busy paths.

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