INTERNET PROGRAMMING INTRODUCTION Software Engineering Branch / 4 th Class Computer Engineering Department University of Technology
ORGANIZATION Lecture Mondays, 08:30-10:30 (Hall 4). Project 1. The project must be an interactive WWW system. Simple HTML pages are not enough 2. Required: server-side programming (e.g. shopping baskets, booking systems, resource allocation). 3. Required: JavaScript (e.g. client-side checking of user input, etc) 4. Not much technical complexity, but a high editorial quality (good layout, including CSS), making the best of the Internet medium 2
OUTLINES History of Internet & World Wide Web The Internet & World Wide Web Access Internet & World Wide Web Architecture of Internet & WWW 3
HISTORY OF INTERNET & WORLD WIDE WEB 1969 The Advanced Research Projects Agency Network ARPANET was the precursor to the Internet. Developed by the Department of Defense in conjunction with several universities, the goal of ARPANET was to allow university-based researchers working for the Defense Department to share information with their colleagues in other U.S. cities. Read more: http://www.lib.utah.edu/ 4
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HISTORY OF INTERNET & WORLD WIDE WEB 1972 Electronic mail is introduced by Ray Tomlinson, a Cambridge, Mass., computer scientist. He uses the @ to distinguish between sender's name and network name in the email address. 6
HISTORY OF INTERNET & WORLD WIDE WEB 1973 Transmission Control Protocol/Internet Protocol (TCP/IP) is designed and in 1983 it becomes the standard for communicating between computers over the Internet. One of these protocols, FTP (File Transfer Protocol), allows users to log onto a remote computer, list the files on that computer, and download files from that computer. 7
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HISTORY OF INTERNET & WORLD WIDE WEB 1976 Presidential candidate Jimmy Carter and running mate Walter Mondale use email to plan campaign events. The date was March 26, 1976, and the ARPANET the computer network that eventually morphed into the internet had just come to the Royal Signals and Radar Establishment, a telecommunications research center in Malvern, England. The Queen Elizabeth was on hand to christen the connection, and in the process, she became one of the first heads of state to send an e-mail. 9
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HISTORY OF INTERNET & WORLD WIDE WEB 1982 The word Internet is used for the first time. 11
HISTORY OF INTERNET & WORLD WIDE WEB 1984 Domain Name System (DNS) is established, with network addresses identified by extensions such as.com,.org, and.edu. 12
HISTORY OF INTERNET & WORLD WIDE WEB 1985 Quantum Computer Services, which later changes its name to America Online, debuts. It offers email, electronic bulletin boards, news, and other information. 13
HISTORY OF INTERNET & WORLD WIDE WEB 1988 A virus called the Internet Worm temporarily shuts down about 10% of the world's Internet servers. 14
HISTORY OF INTERNET & WORLD WIDE WEB 1989 Tim Berners-Lee, introduced a new system of communicating on the Internet which used hyperlinks and a user-friendly graphical interface. His slice of the Internet pie came to be known as the World Wide Web. Read more: http://www.infoplease.com 15
HISTORY OF INTERNET & WORLD WIDE WEB The World Wide Web, or the Web, is often confused with the Internet. In fact, it is just one part of the Internet, along with email, videoconferencing, and streaming audio channels. Read more: http://www.evolutionoftheweb.com 16
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THE INTERNET & WORLD WIDE WEB Internet: is a worldwide public network that connects millions of private networks. For example, on a college campus, the student lab network, the faculty computer network, and the administration network can all be connected to the Internet. Internet 2: is a major cooperative initiative among academia, industry, and government agencies to increase the Internet s possibilities and solve some of its challenges. Internet3: is a large computer network linking smaller networks to one another. World Wide Web (Web): consists of Internet-connected computers called Web servers on which are stored specifically formatted electronic documents called Web pages. Web Page: can contain images, text, interactive elements, and hyperlinks, which are links to other pages. Web Site: is a group of related Web pages. Home Page: typically introduces the Web site and provides information about the site s purpose and content. Hyperlink: is a word, phrase, or image that connects Web pages. 18
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ACCESS INTERNET & WORLD WIDE WEB Telephone Lines Access 1. Public Switched Telephone Network (PSTN) is the worldwide telephone system that handles voice-oriented telephone calls. Although initially built to handle voice communications, the telephone network also is an integral part of computer communications. Data, instructions, and information can be sent over the telephone network using dial-up lines or dedicated lines. 2. DIAL-UP LINES is a temporary connection that uses one or more analog telephone lines for communications. Using a dial-up line to transmit data is similar to using the telephone to make a call. A modem at the sending end dials the telephone number of a modem at the receiving end. When the modem at the receiving end answers the call, a connection is established and data can be transmitted. Internet access using a dial-up line comes in two versions: regular dial-up and high-speed dial-up. 20
ACCESS INTERNET & WORLD WIDE WEB The PSTN generally uses digital technology, with the exception of the final link from the local telephone company to a home or office, which usually is analog. 21
ACCESS INTERNET & WORLD WIDE WEB 3. DIGITAL DEDICATED LINES Unlike a dial-up line in which the connection is reestablished each time it is used, a dedicated line is a constant connection between two communications devices. This constant connection provides a higher-quality connection than a dial-up line. Businesses often use dedicated lines to connect geographically distant offices. 4. Integrated Services Digital Network (ISDN) is a set of standards for digital transmission of data over standard copper telephone lines. With ISDN, the same telephone line that could carry only one computer signal now can carry three or more signals at once, through the same line, using a technique called multiplexing. Multiplexing allows for more data to be transmitted at the same time over the same line. For the small business and home user, an ISDN line provides faster data transmission than a dial-up telephone line at a modest increase in monthly cost. 22
ACCESS INTERNET & WORLD WIDE WEB 5. DIGITAL SUBSCRIBER LINE (DSL) is another digital line alternative for the small business or home user. (DSL) transmits at fast speeds on existing standard copper telephone wiring. Some of the DSL installations can provide a dial tone, so you can use the line for both voice and data. 6. T-carrier line is any of several types of digital lines that carry multiple signals over a single communications line. Whereas a standard dial-up telephone line carries only one signal, digital T- carrier lines use multiplexing so that multiple signals can share the telephone line. T-carrier lines provide extremely fast data transfer rates. The most popular T-carrier line is the T-1 line. Businesses often use T-1 lines to connect to the Internet. A Fractional T-1 line is a less expensive albeit slower connection option for home owners and small businesses. Instead of a single owner, a Fractional T-1 is shared with other users. A T-3 line is equal in speed to 28 T-1 lines. T-3 lines are the most expensive connection method. Main users of T-3 lines include large companies, telephone companies, and service providers connecting to the Internet backbone. 23
ACCESS INTERNET & WORLD WIDE WEB Cable Television Access Cable television (CATV) lines are a very popular type of nonstandard, dedicated telephone line that allows home or business users to connect to the Internet over the same coaxial cable as television transmissions. Data can be transmitted very rapidly through a cable modem connected to a CATV line, typically from 5 to 7 Mbps (download). However, like DSL Internet access, cable Internet access is typically available only in urban and suburban areas. Fixed and Mobile Wireless Access Using satellite technology instead of telephone lines, fixed wireless offers Internet connectivity for users who do not have access to DSL or cable. Radio signals transferred between a transmitting tower and an antenna on a house or business provide a high speed connection up to 2 Mbps. People on the go can access the Internet and Web using mobile wireless technologies, which include radio signals, wireless fidelity (Wi-Fi) technologies, and wireless providers broadband networks. 24
ACCESS INTERNET & WORLD WIDE WEB Internet Service Providers An Internet service provider (ISP) is a business that has a permanent Internet connection and provides temporary Internet connections to individuals and companies using one or more access methods: dial-up, high-speed dial-up, broadband, or wireless. ISPs are either regional or national. A national ISP provides Internet access in most major cities and towns nationwide. National ISPs may offer more services and generally have larger technical support staffs than regional ISPs. An example of a national ISP is EarthLink. 25
ACCESS INTERNET & WORLD WIDE WEB Web Browsers Web browser, also called a browser, which is a software program that requests, downloads, and displays Web pages stored on a Web server. Although browsers are primarily intended to use the World Wide Web, they can also be used to access information provided by web servers in private networks or files in file systems. The major web browsers are Firefox, Internet Explorer, Google Chrome, Opera, and Safari. 26
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ACCESS INTERNET & WORLD WIDE WEB Alternative Web Page Viewing Devices A Smartphone provides regular cell phone service plus offers other features, such as a camera, calendar, and Internet access for e-mail, music downloads, and access to Web pages. A personal digital assistant (PDA) is a popular type of handheld computer used to manage personal information and access the Internet. 28
ACCESS INTERNET & WORLD WIDE WEB Navigating Web Pages To identify a particular Web page s exact location on the Internet, Web browsers rely on an address called a Uniform Resource Locator (URL). The URL is the address of a specific Web page. Every Web page has a unique URL. A URL is a four-part addressing scheme that tells the Web browser: The protocol to use when transporting the file. The domain name of the computer on which the file resides. The path for the folder or directory on the computer in which the file resides. The name of the file. 29
ACCESS INTERNET & WORLD WIDE WEB So in the URL http://www.nytimes.com/pages/sports/index.htm, the http:// is the transfer protocol, which is the set of rules that computers use to move files from one computer to another. The two most common protocols used to transfer files on the Internet are Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP). The second part of the URL, the domain name, is www.nytimes.com and this references the location of the computer on which the Web page resides; www indicates the computer is connected to the Web, nytimes is the name of the Web site, and.com identifies the Web site as being a commercial organization. The /pages/sports portion of the URL provides the path for the folder in which the Web page file is located, and the last portion of the URL, index.htm, is the filename. 30
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ARCHITECTURE OF INTERNET & WWW database mysql server-side programming CGI, PHP ASP Perl Java Servlets network Protocols Application client-side programming HTML CSS Javascript XML 32
ARCHITECTURE OF INTERNET & WWW database server-side network client-side The client-side The client-side is concerned with the Web browser and its supported technologies, such as HTML, CSS, and JavaScript languages and ActiveX controls or Netscape plug-ins, which are utilized to create the presentation of a page or provide interactive features. 33
ARCHITECTURE OF INTERNET & WWW database server-side network client-side The network The network describes the various connectivity elements utilized to deliver the Web site to a user. Such elements may be the various networks on the public Internet or the private connections within a corporation. 34
ARCHITECTURE OF INTERNET & WWW database server-side network client-side programming The server-side This includes the Web server hardware and software as well as programming elements and built in technologies. The technologies can range from simple CGI programs written in PERL to complex multi-tier Java based applications and include backend technologies such as database servers that may support the Web site. 35
REFERENCES 36
Next Lecture Web Documents 37