UNIT 14 INTERNET SERVICES Structure 14.0 Objectives 14.1 Introduction 14.2 World Wide Web .., 14.2.1 Importance of the Web 14.3 How does the Web Work? 14.3.1 Client-Server Architecture 14.3.2 Hypertext Transfer Protocol (HITP) 14.3.3 Hypertext Links: Uniform Resource Locators (URL) 14.4 Web Servers 14.5 Web Browsers 14.5.1 Plug-ins or Helper Programs 14.5.2 Using Web Browser 14.5.3 Toolbar 14.5.4 The Location (URL) Box 14.6 Mark-up Languages 14.6.1 Standard Generalized Mark-up Language (SGML) 14.6.2 Extensible Mark-up Language (XML) 14.6.3 Hypertext Mark-up Language (HTML) 14'.6.4 Dynamic HTML 14.6.5. Virtual Reality Modelling Language (VRML) 14.7 Internet Applications 14.7.1 Internet-based Communication Services 14.7.2 Connectivity 14.7.3 Access to Information Resources 14.7.4 Searching Information Resources on Internet 14.8 Internet for Library Applications 14.8.1 Use of Internet for Supporting Traditional Library Activities 14.8.2 Traditional Library Services Modified in the Internet Era 14.8.3 Internet-based New Library Services 14.9 Summary 14.10 Answers to Self Check Exercises 14.11 Keywords 14.12 References and Further Reading 14.0 OBJECTIVES After reading this Unit, you will be able to acquire knowledge on the following components of Internet: •World Wide Web, its importance and its functioning; • web servers and web browsers and using web browser; • mark-up languages: SGML, XML, HTML, Dynamic HTML and VRML; and • general Internet applications and library-specific Internet applications. 379 Internet Resources and Services 14.1 INTRODUCTION The Internet and web hold tremendous otential for a whole array of activities including online distance education, global digital library, e-commerce, Internet telephony, electronic publishing, electronic journals, virtual museums, etc. It has particularly established itself as a powerful medium for self-education for people in isolated or remote areas for its ease-to-use, familiarity with masses, availability oftools and wider accessibility. The web has become the most successful networked multimedia hyper-text-based system of our time. HTML, the de facto language of the web, is extremely simple yet powerful to use. Further, the static HTML web pages can be transformed into vibrant, dynamic and interactive web creations using ever evolving web technologies like CGI Script, Perl, Java, Javascript, ASP, DHTML,XML and open database connectivity (ODBC) drivers. The rapid growth in the web technology and its ever increasing usage has given librarians and educators with unprecedented opportunities to provide information to the students not within the four-walls of libraries and class rooms but also in the comforts of their home all over the globe. The changes, mainly driven by the new technological innovations and the new learning environment, has presented a scenario where students have access to a vast array of information in many fields from experts all over the world. The Internet allows us to share information and resources such as, government documents, electronic journals, electronic books, media publishing, human anatomical images, computer software, bibliographic and full-text databases, speeches, live concerts, audio and video clippings. The dynamic nature of Internet is derived from scientists, other researchers and general public contributing their time, resources and energies to each other. Typical user" consult electronic resources at near and distant libraries, download computer shareware and software upgrades, read and print publications, make travel arrangements and purchase goods and services. Electronic mail and news groups assist users to communicate with each other on topics of mutual interest. The discussion forum and listserv provides a platform to people with common interest to engage in thoughtful discussions. A few popular modes of usage of Internet are as follows: • Retrieving information from reference sources like dictionaries, encyclopaedias, etc. available on the web, for use in day-to-day work; • Retrieving information from databases of various libraries like the Library of Congress, the British Library, and those of Indian Institute of Science, IITs and several other institutions; • Searching commercial and non-commercial databases like MEDLINE, INSPEC, COMPENDEX, etc.; • Accessing electronic books, e-journals and other e-documents available on the websites of commercial and non-commercial publishers, as required for research work; • Referring social, economic and statistical data, such as, census, daily exchange rates, and government budgets and reports; • Getting documents on fine arts and music, including digital images of art, video and audio; • Exchanging messages with people across the world; • Searching for computer share-ware, freeware, and commercial software; • Sending or receiving sound, animation and picture files across the Internet; Setting up temporary or permanent discussion or work-oriented groups; 380 • • Distributing or reading electronic newsletters, newspapers, bulletins and other Internet Services publications and marketing products and services; • Trading with people of other organisations and other e-commerce activities; and • Chatting with people using software like Yahoo Messengers, Hotmail Messengers, etc. The explosive growth of the Internet and the World Wide Web in recent years has its impact on the information profession too. It has registered a sea change in the information seeking approach as well as the mode of dissemination of information. As librarians and information professionals, our prime responsibility is to acquire, organise, preserve, retrieve, and disseminate pertinent information to our clientele. This global forum, an emerging medium of communication, and a proven and concrete technology in sharing and exchanging information, has a lot to offer to the information professionals. The Internet works on client-server technology, i.e., it works on two types of computer programs, i.e., servers and clients. Servers are programs that host resources to serve the clients and clients are programs that users use to access these resources. E-rnail, listsery / mail lists, Usenet / newsgroups, FTP, Telnet, Gopher, Archie, WWW, etc., are among the prominent services of the Internet. Each type of service in the Internet has its own client. For example, to access the WWW, we need to use a web client such as, 'Netscape' or 'Internet Explorer'. The Internet is a network of networks that connects thousand of networks all over the world. Different types of computers on these networks are made to work seamlessly using TCPIIP (Transmission Control Protocol/Internet Protocol). The TCP / IP protocol, jn turn, is the common name for a collection of more than 100 protocols used to connect computers and networks. 14.2 WORLD WIDE WEB The World Wide Web, known as WWW, W3 or simply, the web, is one of the several Internet resources developed to help people publish, organise and provide access to information on the Internet. The web was first developed by Tim Berners Lee in 1989 while working at CERN, European Particle Physics Laboratory in Switzerl-nd, and has since become the most powerful, and popular, resource discovery tool on the Internet. The WWW can be defined as a hypertext, multimedia, distributed information system that provides links to hypertext documents, as well as to many other Internet tools and databases. 14.2.1 Importanceof the Web' The World Wi e eb is important for libraries because it provides an extremely powerful method of or ising and providing access to information. The Web can provide a single interface to a ge variety of information resources and systems including textual (unformatted or formatted) documents, images, sound and video files. The web can be used to provide interface to other Internet services like TELNET, FTP and Gopher.It can also be interfaced to online databases. There are several features unique to the web that makes it the most advanced hypertext-based information system on the Internet. These features are briefly discussed below: The Web is a Hypertext System: The web is a hypertext system, in contrast to the hierarchical menu system used by earlier Internal tools such as, Gopher. The user on the web moves from one document to another related document through embedded links (called hyperlinks) and a hyperlinked word or phrase, when clicked, calls for another document on that topic. Instead of movirig from menu to menu, as in Gopher, users of the web can jump directly from document to document by clinking on hypertext links. The Web is a Multimedia System: The web is the most successful networked, multimedia, hypertext-based system of our times. The web technology allows incorporation of various 381 Internet Resources media types besides structured text. A good multimedia interactive document is a product and Services consisting of structured text, video clips, animation, pictures, graphics, diagrams, programs, sound, etc. With the advent of graphical browsers, the web has become a multimedia system, combining different types of media into one document. Before the advent of graphical web browsers (e.g., Netscape, Internet explorer), most of the information available on the Internet was in the form of simple text devoid of any elements common to the printed page, such as, text in bold and italics, pictures and other graphical contents. The web documents may contain the following: • Normal text; • . Features such as, large fonts, bold, italic '>, indents; • Images such as, pictures, graphics,