Internet

The Internet is the worldwide network of all computers (or networks of computers) that communicate using a particu-lar protocol for routing data from one computer to another (see tcp/ip). As long as the programs they run follow the rules of the protocol, the computers can be connected by a variety of physical means including ordinary and special phone lines, cable, fiber optics, and even wireless or satel-lite transmission.

History and Development

The Internet’s origins can be traced to a project sponsored by the U.S. Defense Department. Its purpose was to find a way to connect key military computers (such as those controlling air defense radar and interceptor systems). Such a system would require a great deal of redundancy, rout-ing communications around installations that had been destroyed by enemy nuclear weapons. The solution was to break data up into individually addressed packets that could be dispatched by routing software that could find whatever route to the destination was viable or most effi-cient. At the destination, packets would be reassembled into messages or data files.

By the early 1970s, a number of research institutions including the pioneer networking firm Bolt Beranek and Newman (BBN), Stanford Research Institute (SRI), Carnegie Mellon University, and the University of California at Berke-ley were connected to the government-funded and admin-istered ARPANET (named for the Defense Department’s Advanced Research Projects Agency). Gradually, as use of the ARPANET’s protocol spread, gateways were created to connect it to other networks such as the National Science Foundation’s NSFnet. The growth of the network was also spurred by the creation of useful applications including e-mail and Usenet, a sort of bulletin-board service (see the Applications section below).

Meanwhile, a completely different world of online net-working arose during the 1980s in the form of local bulletin boards, often connected using a store-and-forward system called FidoNet, and proprietary online services such as CompuServe and America On-line. At first there were few connections between these networks and the ARPANET, which had evolved into a general-purpose network for the academic community under the rubric of NSFnet. (It was possible to send e-mail between some networks using spe-cial gateways, but a number of different kinds of address syntax had to be used.)

In the 1990s, the NSFnet was essentially privatized, passing from government administration to a corporation that assigned domain names (see domain name system). However, the impetus that brought the Internet into the daily consciousness of more and more people was the devel-opment of the World Wide Web by Tim Berners-Lee at the European particle research laboratory CERN (see Berners-Lee, Tim and world wide web). With a standard way to display and link text (and the addition of graphics and mul-timedia by the mid-1990s), the Web is the Internet as far as most users are concerned (see Web browser). What had been a network for academics and adventurous profession-als became a mainstream medium by the end of the decade (see also e-commerce).

Applications:

A number of applications are (or have been) important con-tributors to the utility and popularity of the Internet.

•  E-mail was one of the earliest applications on the ancestral ARPANET and remains the single most pop-ular Internet application. Standard e-mail using SMTP (Simple Mail Transport Protocol) has been imple-mented for virtually every platform and operating sys-tem. In most cases once a user has entered a person’s e-mail address into the “address book,” e-mail can be sent with a few clicks of the mouse. While failure of the outgoing or destination mail server can still block transmission of a message, e-mail today has a high degree of reliability (see e-mail).

•  Netnews (also called Usenet, for UNIX User Net-work) is in effect the world’s largest computer bul-letin board. It began in 1979, when Duke University and the University of North Carolina set up a simple mechanism for “posting” text files that could be read by other users. Today there are tens of thousands of topical “newsgroups” and millions of messages (called articles). Although still impressive in its quantity of content, many Web users now rely more on discus-sion forums based on Web pages (see netnews and newsgroups).

•  Ftp (File Transport Protocol) enables the transfer of one or more files between any two machines con-nected to the Internet. This method of file transfer has been largely supplanted by the use of download links on Web pages, except for high-volume applica-tions (where an ftp server is often operated “behind the scenes” of a Web link). FTP is also used by Web developers to upload files to a Web site (see file transfer protocols).

•  Telnet is another fundamental service that brought the Internet much of its early utility. Telnet allows a user at one computer to log into another machine and run a program there. This provided an early means for users at PCs or workstations to, for example, access the Library of Congress catalog online. However, if program and file permissions are not set properly on the “host” system, telnet can cause security vulner-abilities. The telnet user is also vulnerable to having IDs and passwords stolen, since these are transmitted as clear (unencrypted) text. As a result, some online sites that once supported telnet access now limit access to Web-based forms. (Another alternative is to use a program called “secure shell” or ssh, or to use a telnet client that supports encryption.)

•  gopher was developed at the University of Minnesota and named for its mascot. Gopher is a system of serv-ers that organize documents or other files through a hierarchy of menus that can be browsed by the remote user. Gopher became very popular in the late 1980s, only to be almost completely supplanted by the more versatile World Wide Web.

•  WAIS (Wide Area Information Service) is a gateway that allows databases to be searched over the Inter-net. WAIS provided a relatively easy way to bring large data resources online. It, too, has largely been replaced by Web-based database services.

•  The World Wide Web as mentioned above, is now the main means for displaying and transferring infor-mation of all kinds over the Internet. Its flexibility, relative ease of use, and ubiquity (with Web browsers available for virtually all platforms) has caused it to subsume most earlier services. The utility of the Web has been further enhanced by the development of many search engines that vary in thoroughness and sophistication (see World Wide Web and search engine).

•  Streaming Media protocols allow for a flow of video and/or audio content to users. Player applications for Windows and other operating systems, and growing use of high-speed consumer Internet connections (see broadband) have made it possible to present “live” TV and radio shows over the Internet.

•  E-commerce, having boomed in the late 1990s and crashed in the early 2000s, continued to grow and proliferate later in the decade, finding new markets and applications and spreading into the developing world (see e-commerce).

•  Blogs and other forms of online writing have become prevalent among people ranging from elementary school students to corporate CEOs (see blogs and blogging).

•  Social networking sites such as MySpace and Face-book are also very popular, particularly among young people (see social networking).

•  Wikis have become an important way to share and build on knowledge bases (see wikis and Wikipedia).

•  The integration of the Internet with traditional chan-nels of communications is proceeding rapidly (see podcasting, Internet radio, and VoIP).

Even as it begins to level off in the United States, world-wide Internet usage continues to grow rapidly. Asia now has more than twice as many users as North America, although the latter still has more than five times the penetration (percentage of population).

In the United States more than half of Internet users have high-speed Internet connections (see broadband), and the trend in other developed countries is similar. Broad-band is both required by and contributes to the appetite of Web users for music, streaming video, and other rich media content (see streaming and music and video distribu-tion, online).

Now in its fourth decade, the Internet is not without daunting challenges. A major one is security—see com-puter crime and security, computer virus, cyber-terrorism, and information warfare. Users also want protection from privacy abusers and online predators (see privacy in the digital age, identity theft, phishing and spoofing, and cyberstalking and harassment).

For other issues and challenges involving the Internet, see censorship and the Internet, Internet architec-ture and governance, Internet access policy, and digital divide.

In the longer term what we call the Internet today is likely to become so ubiquitous that people will no longer think of it as a separate system or entity. Household appli-ances, cars, cell phones, televisions, and virtually every other device used in daily life will communicate with other devices and with control systems using Internet protocols. In effect, people may eventually live “inside” a World Wide Web.