The Servlet Story
Once upon a time there was a lot of political testosterone. Responding to USSR's superpower-defining Sputnik satellite, the U.S. formed the Advanced Research Projects Agency (ARPA) in 1957. In those days computers were living in digital Babylon as none could understand its neighbor. Four years later, Leonard Kleinrock (MIT) wrote "Information Flow in Large Communication Nets," the first paper on packet-switching theory. MIT kept leading the way when in 1966 Lawrence G. Roberts proposed the first wide-scale network, known as the ARPANET plan. The Department of Defense (DoD) acknowledged the academics by, what turned out to be pivotal, commissioning the ARPANET in 1969. The ARPANET team rewarded the DoD by establishing the Network Control Protocol (NCP), the first host-to-host protocol, making it possible for university and research center computers to call each other.
Glad for the new business, AT&T installed the first cross-country link between UCLA and BBN. The world didn't know it at the time, but a vortex was born; something other than people was causing busy signals. By 1973, hundreds of computers between organizations, even across the ocean, were shoveling data to each other.
While the cross-country communication gap between industrial goliaths shortened, market pressure mounted for a way to connect PCs in the same room. That is when Bob Metcalfe invented Ethernet, which Xerox PARC helped to build. Then in 1974, Vint Cerf and Bob Kahn published a distance network scheme that eventually became the TCP/IP standard (1982). In this standard, several ideas found solid footing including Usenet, email, and others. In a related development, the Domain Name System established itself, which kicked the number of hosts up past 1,000 (1984).
In 1987, the National Science Foundation signed a cooperative agreement to manage the nascent Internet (NSFNET) backbone, weakened by multiplying hosts which had shot past 10,000 that year but reached several hundred thousand hosts by 1991. There was nobody in charge and the digital anarchy irritated one scientist. In 1991, Tim Berners-Lee was fed up with the way electronic documents worked, so he created hyperlinks. Not one to go partway, he needed links to talk to each other, so to make that possible he invented a whole protocol which he christened the World Wide Web.
The WWW crawled into a crowd as Gopher, WAIS, telnet, email, and many other services ruled the networks. All the activity and growth numbers were impressive, but no one was ready for what came next. In 1993, Marc Andersen and pals wanted to see what was on the Internet, so they developed a new computer program called the NCSA Mosaic (National Center for Supercomputing Applications at the University of Illinois) based on Berners-Lee's contraption. They gave it away!
Mosaic started a worldwide frenzy: The Internet exploded. Even the most optimistic proponents were shocked. In less than a decade, the number of hosts snowballed to nearly 200 million and the number of users approached one billion!
There is more news in the making. The Net is being invaded by a swarm of aliens that will dwarf the human user count. With the advent of Internet capability in non-PC devices including phones, GPS, PDAs, and even cars and refrigerators, the Internet is about to mushroom again as devices using the Net multiply, outnumbering people by several orders of magnitude.
Remarkably, the Internet is only a teenager. Our prodigy has no idea what it will do when it grows up. So, let's help it decide. As you will see in the next chapters, servlets and JSPs are tools we can use to direct all those bytes down the straight and narrow path. It is at the juncture between users and repositories where the Internet struggles most. If we could just close this distance, even a little, then our contribution will be very valuable. Admittedly, Java has its disappointments (Gosling and gang simply copied switch blocks from C without adding value such as allowing strings), but servlets are mighty because they have access to the entire Java API. Since JSPs metamorphose into servlets, the technology is very effective. It gives us intelligent bricks to build a wall around embattled OS warlords, rendering all their wares into one virtual platform.