IBM i5/iSeries Primer(c) Concepts and Techniques for Programmers, Administrators, and Sys[... ]ators

If you are already familiar with the concepts and terms relating to the Internet, you can skip this section. This is by no means a complete list of all the terms you will hear about the Internet, but it should be enough to get you started.

• Firewall. A hardware and software system that protects your computers against unauthorized access from the outside world.

• Hacker. Any person who tries to gain unauthorized access to your computer.

• HTML (Hyper-Text Markup Language). The programming language used to indicate how your document should appear when presented on the screen. It can be used to control highlighting and type style. It can also be used to control linking to other objects or other places inside a document.

• Hypertext. A way of providing a word or phrase that can be used to link to another piece of information, or even another document. You click on hypertext and, through a hypertext link, you are presented with more information regarding the hypertext.

• Internet. A worldwide network of computers that have all agreed to use the same communication protocols (set of rules) and suite of cooperation applications to communicate with each other.

• Internet client. A user (or program) that requests information from an Internet server program; for example, a Web browser.

• Internet name. A user-friendly name for an Internet Protocol address. Your actual Internet address will be a long string of numbers, but you can be accessed by your Internet name, such as http://www.myname.com.

• Internet Protocol (IP) address. An IP address is a string of numbers that uniquely identifies your computer to the rest of the world. An IP address is usually represented as four decimal numbers, grouped by periods; for example, 255.255.255.0.

• Internet server. A program that accepts and responds to requests from an Internet client. A File Transfer Protocol (FTP) program is one example.

• Internet Service Provider (ISP). The Internet service provider provides a connection to the Internet. You connect to the ISP (usually with a local phone call or through a cable modem), and it provides connections to the Internet (anywhere in the world). It also stores your computer name and address and makes it available to the rest of the world through temporary IP addresses.

• Intranet. An internal network of computers that uses Internet tools (such as a Web browser). This network is not open directly to the public, but you can connect your intranet to the Internet.

• IP Datagram. An IP Datagram is a unit of information (such as the IP address of the source and target computers) that is sent across a TCP/IP network.

• Packet. A datagram with more information about the line protocol.

• Router. Hardware used to control and direct packets to the correct destination.

• Transmission Control Protocol/Internet Protocol (TCP/IP). The set of rules governing communications between computers connected via the Internet.

• Web browser. A Web browser is a set of programs that interprets HTML to display hypertext documents for the user. It's what you, as a user, use to access information on other computers. It is your interface to the Internet.

• World Wide Web. All the interconnected computers that have agreed to use a standard format for creating and accessing documents. It uses HTML to create documents and HTTP to access them.