In 1963, the Advanced Research project Agency (APRA) unit, set up by the the US defence department began to build a computer network. Driven by fear of the Soviet nuclear threat, it aimed to link computers at different locations, so researchers could share data electronically without having fixit routes between them, making the system less vulnerable to attacks- even nuclear ones.
Data was converted into telephone signal using a modem (modulator- demodulator), developed at AT&T in the late 1950 s. In the 1960s, key advances where made, including “packet switching” – the system of packaging, labelling and routing data that enables it to be delivered across the network between machines. Paul Baran (b. 1926) proposed this system, which broke each message down into tiny chunks. This would be fired into the network which would then route switch the various pieces to the desired destination.
“Getting information off the Internet is like taking a drink from a fire hydrant”.Mitchell Kapoor, software designer
So, if chunks of a message where travelling from Seattle to New York via Dallas, but Dallas suddenly went offline, the network would automatically route via Denver instead. Different Parts or packets of a message would go by different routes, before being reassembled back into the original message at their destination, even if they arrived in the wrong order. Baran published his concept in 1964, and five years later the new network- called APRANET – went live.
As the threat of nuclear war receded in the early 1970s, APRANET was renamed the Internet and effectively opened to all users. Since then, the development of e-mail, the creation of the World Wide Web ( WWW) , and browser technology has enabled the Internet to become a rich communications facility.
ETHERNET ( 1973):
In 1973, Bob Metcalfe Xerox Palo Alto Research centre (PARC) faced a problem. Increasing numbers of computers were bringing up around him all of which needed to be connected to each other. Just down the hallway the world’s first laser printer invented at PARC in 1971 was hungry for documents. Computer networking was in its infancy. The hardware was expensive and wiring at PARC looked like an explosion in a spaghetti factory. Any glitch in the computers or the cabling would bring down the whole system.
Today, Ethernet stands as the dominant networking technology…The Economist (2003)
Metcalfe was given the job of building a simpler more reliable computer network. Desperate for inspiration from any source he stumbled across the university of Hawaii’s ALOHAnet radio network. Unlike most computer networks which were carefully regulated so only one computer could talk to another at any given moment, ALOHAnet was a free for all. If several computers tried to talk at the same time each computer would back off for a little while before trying again. Constantly developed ever since, Ethernet is now the most popular standard for local networks, if you send a document to your officer printer today, it is likely to travel down the wires of an Ethernet based network, directly descended from Metcalfe’s work.