>Intergalactic Computer Network? I saw that on Star Trek! Remember when Captain Kirk ...?
- In 1962, J.C.R. Licklider
of MIT (in a historic memo addressed to "Members and Affiliates of the Intergalactic Computer Network")
discussed a Galactic Network concept whereby globally connected computers could quickly access data
and programs from any site. Licklider became the first head of the computer research program at the Advanced Research Projects Agency
... known as ARPA (created by President Dwight Eisenhower as a response to the USSR's launch of sputnik in 1957).
>$2 Billion? Wow! So they invented the World Wide Web, eh?
- ARPA (within the Department of Defense ) was given a $2B budget. It later became the Defense Advanced Research Projects Agency (DARPA),
then ARPA again, and now (since 1996) DARPA ... again.
No. Wait for it, okay?
>A dedicated phone line? What a phone bill! But then, with $2B ...
- In 1965, as a test of the Licklider's idea, Lawrence Roberts of MIT
and fellow researchers connected the
TX-2 computer in MIT's Lincoln Labs
to Thomas Marill's Q-32 computer at
System Development Corporation in Santa Monica, California using a dedicated phone line.
>Huh? Full-duplex? Circuit-switched?
- The phone line was a special Western Union four-wire full-duplex service. Marill attached a modem operating at 2,000 bits per second,
referring to the transfer of messages between computers as a message “protocol.”
- Although the experiment proved that computers could talk to each other over large distances, it also showed that a circuit-switched telephone system was inadequate
for a successful network.
Full-duplex means the information can go both ways, as in a normal conversation. In half-duplex I can talk to you but you can't talk back
... which would be nice.
>Yeah, funny, but what about circuit-switched?
Phone lines are circuit-switched. Communication requires a dedicated line between the two users. Nobody else can use that line while they're communicating
with each other.
>And if a thousand users want to talk to each other?
Now we're talking packet-switching.
>The software at the receiving end? What about ...?
- Leonard Kleinrock, while a graduate student at MIT, published the first paper on
packet-switching theory in 1961
(Information Flow in Large Communication Nets)
- In packet-switching, many users are connected to a common line and the information they want to send is divided into "packets" which are then
inserted into the network. The users each have their own addresses and each packet has the address of the intended recipient. These packets may arrive at
their destination by various routes.
- The software at the receiving end assembles all the packets for a given message, thereby reconstituting the original message.
The software at the sending end? Yes. It must break up your message into packets. The standard for data transmission over the Internet is
Transmission Control Protocol/Internet Protocol (TCP/IP)
>Is that one or two pieces of software?
Well, as I understand it, IP specifies the format of the packets and associated Web addresses:
(Click here to see your IP Address ... and other neat info concerning where you're from.)
TCP enables two computers to establish a
connection and exchange streams of data, guaranteeing that packets will be delivered in the same order in which they were sent.
- In 1967, Lawrence Roberts
presented a paper on his ideas concerning a computer network: ARPANET.
(The first two nodes that formed the ARPANET, in 1969, were UCLA and the Stanford Research Institute.)
- At that same conference, Donald Watts Davies
of the National Physical Laboratory (NPL) in Middlesex, England presented a paper on packet-switching.
(It was actually Davies who coined the word "packets".)
>Yeah, so who invented this packet-switching thing?
Who do you want to believe? It's like asking: "Who invented the computer?" For example, take a look at
You read things like:
Leonard Kleinrock, inventor of Internet technology.
Donald W. Davies made the Internet possible.
Lawrence G. Roberts, founder of the Internet.
Paul Baran, founding father of the Internet.
>And Al Gore?
Uh ... yes. He said (in a
interview with Wolf Blitzer):
"During my service in the United States Congress, I took the initiative in creating the Internet.".
Gore never claimed that he invented the Internet but rather, as a senator, that he promoted the Internet, calling for financial support for
basic research of computer networking.
However, finding the jokes about his "inventing" the Internet amusing, he also joked :"I invented the environment."
Then, following the multitude of jokes:
- President Bill Clinton joined the frivolity, joking to the Gridiron Club a week after the CNN interview:
Al Gore invented the Internet. For the record, I, too, am an inventor. I invented George Stephanopoulos.
- Senate Majority Leader Trent Lott issued a news release claiming that he invented the paper clip.
- Dan Quayle said, If Gore invented the Internet, then I invented Spell-Check.
- David letterman said:
Although he didn't invent the Internet, he did invent those annoying bits of punctuation that look like sideways faces :-)
as well as:
While riding his bicycle one day, Gore accidentally invented the orgasm
>Okay, but who's Paul Baran?
Paul Baran worked at RAND
and conceived of a network of computers and a
method of communication
... what would become known as packet-switching. The computers in the system
constituted a system of "nodes". When a node receives a "packet" it determines the best route to send it to the next node until, eventually, the packet
arrives at its final destination.
As it turns out, several groups were working independently on the same idea:
A network of computers that could comunicate with each other
>Instead of a computer as just a computing machine, eh?
Exactly. ARPANET incorporated the best ideas of the teams at MIT, NPL and the RAND corporation
>So ARPANET is the World Wide Web, eh?
No. Wait for it, okay?
Remember when Sir Isaac Newton explained:
If I have seen further it is because I have stood on the shoulders of giants.
>No. I was very young then and ... ?
In the same way, the primary inventor of the Web, Tim Berners-Lee, acknowledges
"The Web revolution depended on a much quieter revolution - the Internet revolution."
Sir Tim Berners-Lee. He proposed the WWW in 1989.
He was knighted just a few months ago
>In 1989? But that ARPA-stuff had been around for a while, eh?
Yes. I can recall being at a research centre in Italy and communicating with my wife (in Canada) every morning ... via a University of Waterloo computer. She
phoned the university via a modem, connected to a UW computer and typed a message with a simple text editor. Then she'd send the message (text only!) to my Italian
address and it went via a host of nodes to the computer in Italy. That was about ten years before the World Wide Web.
>So you speak Italian?
Sure ... pizzaria, pasta and Gina Lollobrigida.
Lollobrigida, but that was before your time, eh?
>What does she have to do with the World Wide Web?
Nothing that I know of ...
the World Wide Web
first proposed the basics of hypertext in 1945. He called it Memex and it described how one might link various books, records, tables etc.
for rapid access.
Years later, Tim Berners-Lee invented HTML (hypertext markup language) which is now used to display web pages. For example, one writes
(using a simple text editor) some strange collection of characters called HTML tags (like <OL> and <LI> and <B> ) along with simple text
(like the right-side, below) and a "web browser" (in this case, "Netscape") interprets the HTML and displays what is shown in the left-side):
Tim Berners-Lee, as the primary author of HTML, was assisted by his colleagues at
(Conseil Européen pour la Recherche Nucléaire), an international scientific organization based in Geneva, Switzerland.
The idea was to simplify communication between scientists at CERN. In fact, his proposal was called: HyperText and CERN
In addition to HTML to write web documents, Tim Berners-Lee also invented HTTP (HyperText Transfer Protocol) to transfer web documents
and the addressing system: URLs (Universal Resource Locators) ... in 1990.
>HTTP? As in http:/www.etc.etc.
You got it.
The computer that held the collection of HTML documents CERN called a "Web Server". There was just one such server at CERN
... originally, in 1991. They made the HTML documents and WWW techniques generally available to all and encouraged others to provide servers.
By 1992, there were 50 servers in the world.
By 1999 there were 720,000 servers.
By 2001 there were 23 million.
Of course, one needed a "browser" to interpret the HTML documents (prototypes of current browsers such as Explorer or Netscape).
Although CERN created such a browser, in 1993
(an undergraduate student at the University of Illinois) working on a project for the National Center
for Supercomputing Applications (NCSA) led a team that developed the graphic interface browser called Mosaic.
You just point and click.
>Hey! That's what I do!
Yes. People without any computer expertise (like you!) were able to use the Mosaic graphical interface and just point and click
to navigate the World Wide Web. Andreesen left NCSA in 1994 and, with Jim Clark, formed a company later known as ...
>Don't tell me! It was Microsoft!
No, it was Netscape Communication Corporation.
>So, what's Berners doing for an encore?
one million euros (in June, 2004) as the first recipient of the Millennium
Technology Prize, awarded by the Finnish Technology Award Foundation, he's apparently working on a
next-generation version of the World Wide Web enabling computers to understand what they are processing.
A difficult task if ...
>If it's gibberish?
Uh ... yes.