Chapter 8

On CGI Programming

     The Internet is a product of the US military’s efforts dating back to the late 1960s. For a long time, the use of the Internet was restricted to the military and selected academic and research institutions in the US. In the 1980s, the number of academic and research institutions connected to the Internet proliferated rapidly. However, the Internet was still restricted to non-commercial use. The situation changed dramatically when in the early 1990s, the US Government opened the Internet for potential commercial use. A very lucid book on the Internet that discusses its history, the technologies that have made the Internet feasible, and the applications of the Internet is the Internet
Book [Com00].

   The expansion of the Internet to public and commercial domains accelerated at a rapid pace due to a simple but earth-shattering invention called the World Wide Web in 1989 by the physicist Tim Berners-Lee working in a European nuclear research institution in Switzerland. He proposed a client and server set-up to serve documents dispersed across Europe as a connected and coherent network so that scientists could easily share experiences and results of their experiments. The first Web client and server were written and demonstrated by Berners-Lee in 1990. The first implementation dealt exclusively with text documents with links to other documents or hyperlinks.

     The first Web client or browser with a graphical user interface was written in the US at the National Center for Supercomputing Applications (NCSA) at the University of Illinois in Champaign-Urbana in 1993. It was called Mosaic and was available for free downloading on the Internet. Millions of copies were quickly downloaded and in a sense, the Internet revolution really started. Mosaic could display graphic images and was easy and pleasant to use with a point-and-click interface. Soon afterwards, Marc Andressen, one of the undergraduate student project leaders on the Mosaic project moved to California and started the company called Netscape. The Web client or browser called the
Netscape Navigator was soon released. Microsoft Inc., although a late starter in Internet software production, re-engineered itself in the mid-1990s and released its Internet browser, the Internet Explorer in 1996. These are the two main Web clients at this time.

 The Web has changed society in general. It is available across the globe, from the richest countries to the poorest. It has revolutionized human communication. It has rapidly become a medium for commercial communication, among far-flung divisions or departments of companies. It also has changed how governments at all levels communicate with the public and the ruled. It has also already become the marketplace of the world where anything conceivable from anywhere is available for buying and selling with the click of a mouse. The Web has also become a hotbed of entertainment possibilities with music, video and other data files being transmitted easily across the globe. Hundreds of TV and radio
stations are available on the Web at this time.

Perl has been an important language in the development of the Web, with Perl-based CGI programs leading the way in delivering dynamic Web pages by collecting and collating information from disparate sources. Perl works easily with a Web server such as the leading Apache server. With its strong networking capabilities, powerful string handling, and a large number of enthusiastic followers who write and distribute free quality software, it is easy to develop sophisticated CGI programs and Web clients in Perl. Perl plays a major role on the Web and will continue to do so for the foreseeable future.