CIBM- BUSINESSINFORMATION SYSTEMSChapter Eight- From the Internet to theinformation super highway
8.1 THE INTERNET: A NETWORKOF NETWORKS The Internet is an interconnected network of thousands of networks linking academic, research, government, and commercial institutions, other organizations, and individuals. The Internet is a technology, a tool, and a culture. It was originally designed by computer scientists for computer scientists, but today it’s used by people in all walks of life all over the world. The Internet provides scientists, engineers, researchers, educators, students, business people, consumers, and others with a variety of services, including: Electronic mail (e-mail) Web publishing Instant messaging Network newsgroups Banking Research
8.1.2 INTERNET PROTOCOLS The protocols at the heart of the Internet are called TCP/IP (Transmission Control Protocol/Internet Protocol). They were developed as an experiment in internetworking—connecting different types of networks and computer systems. The TCP/IP specifications were published as open standards, not owned by any company. They define how information can be transferred between machines and how machines on the network can be identified with unique addresses.
8.1.3 INTERNET ACCESS OPTIONS There are three common ways users can connect their computers to the Internet to take advantage of some or all Internet services: Direct (dedicated) connection, which provides the fastest, most reliable service. Dial-up connections use a modem and standard phone line. A full-access dial-up connection offers most of the advantages of direct connection, but is limited by modem speed. Broadband connections include DSL, cable modem connections, and satellite connections.
INTERNET SERVICE PROVIDERS(ISPS) Offer several connection options at different prices. In some cities inexpensive or free access to the Internet is available through a free net— a local bulletin board system designed to provide community access to on-line forums, announcements, and services. Many computer networks, bulletin board systems, and on-line services provide varying degrees of Internet access through gateways. A gateway is a computer connected to two networks—in this case, the Internet and an outside network—that translates communication protocols and transfers information between the two.
8.1.4 INTRANETS AND EXTRANETS For many organizations, Internet protocols and software are more important than the Net itself. Members of these organizations communicate through intranets—self-contained intraorganizational networks that are designed using the same technology as the Internet. Some private TCP/IP networks are designed for outside use by customers, clients, and business partners of the organization. These networks, often called extranets, are typically for electronic commerce—business transactions through electronic networks.
8.2 INTERNET APPLICATIONS:COMMUNICATION AND CONNECTION Working with Internet applications is different from working with word processors or spreadsheets because of the distributed nature of the Internet and the client/server model used by most Internet applications. In the client/server model, a client program asks for information and a server program fields the request and provides the requested information from databases and documents. Two different users might access the same server using completely different client applications with different user interfaces.
8.2.1 INTERNET ADDRESSES The most popular reason for connecting to the Internet is electronic mail. You can send messages to anyone with an Internet link, provided you know his or her Internet address. A person’s e-mail address is made up of two parts separated by an “at” sign (@)—the person’s user name (login name), and the host name—the name of the host computer or network where the user receives mail. Here’s the basic form: study@Regent.ac.za. The host is named using what’s called the domain name system (DNS)—a system that translates the computer’s numerical IP address into something that’s easier for humans to read and remember. The DNS uses a string of names separated by dots to specify the exact Internet location of the host computer. The words in the domain name are arranged hierarchically from little to big.
8.2.2 E-MAIL ON THE INTERNET Basic e-mail can be handled by a character-based program like PINE or (if you have a full Internet connection) a graphical client program like Netscape, Microsoft Outlook Express, or Eudora. Standard Internet mail messages are plain ASCII text. Formatted word processor documents, pictures, and other multimedia files usually need to be temporarily converted to ASCII using some kind of encoding scheme before they can be sent through Internet mail; these encoded documents are sent as attachments to text messages.
8.2.4 NETWORK NEWS You can participate in special-interest discussions and debates without overloading your mailbox by taking advantage of the hundreds of Usenet newsgroups. These are public discussions that you can check into and out of whenever you want; all messages are posted on virtual bulletin boards for anyone to read. Newsgroups are organized hierarchically, with dot names like rec.music.makers.percussion and soc.culture.french. To explore network newsgroups, you need a client program that can serve as a news reader.
8.2.5 REAL-TIMECOMMUNICATION Mailing lists and news groups are delayed, or asynchronous communication, because the sender and the recipient don’t have to be logged in at the same time. The Internet offers programs for real-time communication, too. Text-based options include Talk and Internet Relay Chat (IRC). Newer, easier to use instant message systems such as AOL’s allow users to create “buddy lists” and chat with “buddies” who are logged in. Many new programs allow you to use a computer’s microphone and speaker to turn the Internet into a toll-free long distance telephone service. Some even allow two-way video teleconferences.
8.2.6 TELNET AND FTP To find and retrieve information located on remote Internet sites, Net explorers have traditionally used two software tools: remote login and file transfer. Remote login allows users to connect to hosts all over the world from just about anywhere. The protocol that makes remote login possible is called telnet, which is also the name of the UNIX command that’s used for remote login and the name of a program that executes the Telnet command from directly connected Macintosh and Windows PCs.
FILE TRANSFER PROTOCOL The Internet’s file transfer protocol, commonly called just FTP, can transfer files from remote sites to users’ host computers. Many sites allow anonymous FTP so you can collect files without officially logging in. Most files in net archives are compressed—made smaller using special encoding schemes. Compression saves storage space on disks and saves transmission time when files are transferred through networks.