Nikola Tesla and J.C.R. Licklider both talked about a worldwide network of computers. Licklider referred to it as an “Intergalactic Network.”
The internet evolved slowly over time. At first, it wasn’t much more than a series of specifications, ideas about how computers might talk to one another. Eventually, towards the late 1960s, these turned into a working system connecting a small number of computers.
The Advanced Research Projects Agency, an arm of the US military that funds far-out projects, funded the early internet, called ARPANET.
Unless you had a Ph.D. in computer science the early internet was dull and didn’t do much. Quoting one source: “ARPANET showed almost no sign of ‘useful interactions that were taking place on [it].'” However, it did use packet switching to connect computers. Simplifying, packet switching involves breaking information into pieces for transmission between computers.
Eventually, ARPANET grew but the clunkiness of early packet switching left the network unstable. Significantly, data would be scrambled and if a computer was off messages could go into a black hole. Worse, all computers needed to be physically wired to one another. There was no way to use interim computers (hosts) to route packets further along. This severely limited the ability of the young network to grow.
Two technologies changed that. During the late 1970s and early 1980s Internet pioneers, Vinton “Vince” Cerf and Bob Kahn developed transmission control protocol (TCP) and internet protocol (IP).
Specifically, transmission control protocol (TCP) is a set of rules specifying how to break the information into pieces, how to ensure the packets arrive complete, how to reassemble the packets, and how to ask for a new one if a packet arrives scrambled.
Furthermore, internet protocol (IP) is a series of rules about routing the packets between computers. Significantly, internet protocol automatically re-routes packets. When hosts are down packets automatically re-route. This ability, to route information around broken or malfunctioning computers, explains the military’s early interest.
With the implementation of TCP/IP the internet was able to grow at an exponential speed. Eventually, computers anywhere could easily connect to the network.