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By National Science and Media Museum on

A brief history of the internet

Trace the history of the internet, from its 1950s origins to the world wide web’s explosion in popularity in the late 1990s (and beyond).

The origins of the internet are rooted in the USA of the 1950s. The Cold War was at its height and huge tensions existed between North America and the Soviet Union. Both superpowers were in possession of deadly nuclear weapons and people lived in fear of long-range surprise attacks.

The climate of fear within the US was amplified by the shock launch of the Soviet satellite, ‘Sputnik 1’ in 1957. The Sputnik 1 satellite was the first man-made object to orbit the Earth and could circle the planet in just 96 minutes. The Soviet Union’s demonstration of its scientific superiority led US President Dwight D. Eisenhower to form the Advanced Research Projects Agency (ARPA) in 1958.

ARPA brought together some of the best scientific minds in the country. Their aim was to help American military technology stay ahead of its enemies and prevent surprises, such as the Sputnik launch, happening again. The Cold War was fundamental in opening up new funding for groundbreaking research in a wide array of sciences, including nuclear power/weapons, space technology and computers.

Computers in the 1950s were large, expensive machines exclusively used by military scientists and university staff. The new machines were powerful but limited in numbers, and researchers grew increasingly frustrated as they required access to the technology but had to travel great distances to use it.

At the same time as the formation of ARPA, Paul Baran—an engineer at the American think tank the RAND Corporation—was asked to research how the US Air Force could keep control of its fleet if a nuclear attack ever did occur. In 1964 Baran proposed a communication network with no central command point. If one point was destroyed, all surviving points would still be able to communicate with each other. He called this a distributed network.

Paul Baran’s idea for a new type of distributed network appealed to Lawrence Roberts, the chief scientist at ARPA, who was responsible for developing computer networks. Building on the conceptual work of fellow American scientists, J.C.R. Licklider and Leonard Kleinrock, Roberts made two separate computers in two different places talk to each other for the first time in 1965. Roberts’ two-computer experimental link used a telephone line with an acoustically coupled modem and transferred digital data using ‘packets’.

A ‘packet’ is a small chunk of data that can vary in size but is typically around 1500 bytes, or 1500 characters. A large message is split into thousands of individual, equal-sized packets. The theory of packet-switching was developed by Kleinrock and Roberts, unknowingly in parallel to the work being done on the other side of the Atlantic by a British scientist called Donald Davies at the National Physical Laboratory (NPL) in Middlesex.

Packet switching is the technique of sending packets over a distributed network. Each packet is sent individually on different routes through the network and then reassembled in the right order when it arrives at its final destination. The packet switching method is very reliable and allows data to be sent securely, even over damaged networks. Another big advantage of packet switching is that it uses bandwidth very efficiently and doesn’t need a single dedicated link, like a telephone call does.

The world’s first packet-switching computer network was produced in 1969. Computers at the University of California Los Angeles (UCLA), the Stanford Research Institute (SRI), the University of Utah and University of California Santa Barbara (UCSB) were connected using separate minicomputers known as ‘Interface Message Processors’ or ‘IMPs’. The IMPs acted as gateways for the packets and have since evolved into what we now call ‘routers’.

Leonard Kleinrock at UCLA sent the first message across the network to the Stanford computer. Kleinrock tried to type ‘login’ but the system crashed after the letters ‘L’ and ‘O’ had appeared on the far-off monitor. A second attempt proved successful and more messages were exchanged between the two sites. The ARPANET was born.

More computers were quickly connected to the ARPANET: by 1973, 30 academic, military and research institutions had joined the network. Radio links connected the ALOHA nodes in Hawaii; a satellite connected computers across the Atlantic in Norway and Davies’ NPL network in the UK.

As more networks of computers attempted to join ARPANET, an agreed set of rules for handling the packets needed to be put in place. In 1974 two American computer scientists, Bob Kahn and Vint Cerf, proposed a new method to send the packets through a network in a digital envelope or ‘datagram’. The address on the datagram can be read by any computer but only the final host machine can open the envelope and read the message inside. The method was called transmission-control protocol and became popularly known as TCP/IP. TCP/IP allowed computers to speak the same language, and ARPANET quickly grew to become a global interconnected network of networks, or ‘Internet’.

When asked to explain my role in the creation of the internet, I generally use the example of a city. I helped to build the roads—the infrastructure that gets things from point A to point B.

—Vint Cerf, 2007

Cheaper technology and the appearance of desktop computers in the early 1980s allowed the rapid development of local area networks (LANs) and the internet flourished. An increase in the amount of computers on the network made it difficult to keep track of all the different IP addresses. This problem was solved by the introduction of the Domain Name System (DNS) in 1983. Invented by Paul Mockapetris and Jon Postel at the University of Southern California, the DNS is the phone book of the internet and converts hard-to-remember IP addresses into simple names.

IP stands for Internet Protocol and, when combined with TCP, helps internet traffic find its destination. Every device connected to the internet is given a unique IP number. Known as an IP address, the number can be used to find the location of any internet-connected device in the world.

The invention of DNS, the common use of TCP/IP and the popularity of email caused an explosion of activity on the internet. The network suddenly swelled from 2000 hosts in 1986 to 30,000 by the end of 1987. People could now send messages to each other, read online news and swap files over the network, but it wasn’t straightforward. An advanced knowledge of computing was still needed to dial in to the system and use it effectively.

The internet needed to be easier to use, and an answer to the problem appeared in 1989 when a British computer scientist named Tim Berners-Lee submitted a proposal to his employer, CERN, the international particle-research laboratory in Geneva, Switzerland. Berners-Lee proposed a new way of structuring and linking all the information available on CERN’s computer network that made it quick and easy to access.

Berners-Lee’s proposed ‘web of information’ relied on ‘hyperlinks’ to connect documents together. Written in Hypertext Markup Language, or HTML, a hyperlink can point to any other HTML page, image, audio track or video file that sits on top of the internet.

In 1990, Berners-Lee developed the Hypertext Transfer Protocol and designed the Universal Resource Identifier system. HTTP is the language computers use to communicate HTML documents over the internet and the URI (also known as a URL) provides a unique address where the pages can be easily found.

Tim Berners-Lee also created a piece of software that could present HTML documents in an easy-to-read format. He called the ‘browser’ the ‘WorldWideWeb’. The application had limited use as it could only be used on advanced NeXT machines. A simplified version that could run on any computer was created by Nicola Pellow, a visiting maths student from Leicester Polytechnic, UK.

On 6 August 1991 the code to create more web pages and the software to view them was made freely available on the internet. Computer enthusiasts around the world began setting up their own websites. Berners-Lee’s vision of a free, global and shared information space began to take shape.

The dream behind the Web is of a common information space in which we communicate by sharing information. Its universality is essential: the fact that a hypertext link can point to anything, be it personal, local or global, be it draft or highly polished.

—Tim Berners-Lee, 1998

In 1993, Marc Andreessen, an American student in Illinois, launched a new browser called Mosaic. Created at the National Center for Super-computing Applications (NCSA), Mosaic was easy to download and install, worked on many different computers and provided simple point-and-click access to the World Wide Web. Mosaic was also the first browser to display images next to text, rather that in a separate window.

Mosaic’s simplicity opened the web up to a new audience of non-academics and people started to discover how easy it was to create their own HTML web pages. This caused an explosion of activity on the internet: the number of websites grew from 130 in 1993 to over 100,000 at the start of 1996.

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