An Ars Technica history of the Internet, part 1 - Ars Technica

I've read about the birth of the Internet many times. The stories of the IMP, Interface Message Processors, and their 24kb of memory are delightful. I love the paper sketch in this article showing the first four IMPs connected.

The real unlock here though is around the development of TCP/IP. If there is one thing that unlocked the magic, it was that. And it is a damn shame that everyone knows who Mark Zuckerberg is but not many can tell you who Vint Cerf is.

Robert Kahn asked Vint Cerf to try and fix these problems once and for all. They came up with a new plan called the Transmission Control Protocol, or TCP. The idea was to connect different networks through specialized computers, called "gateways," that translated and forwarded packets. TCP was like an envelope for packets, making sure they got to the right destination on the correct network. Because some networks were not guaranteed to be reliable, when one computer successfully received a complete and undamaged message, it would send an acknowledgement (ACK) back to the sender. If the ACK wasn't received in a certain amount of time, the message was retransmitted.

In December 1974, Cerf, Yogen Dalal, and Carl Sunshine wrote a complete specification for TCP. Two years later, Cerf and Kahn, along with a dozen others, demonstrated the first three-network system. The demo connected packet radio, the ARPANET, and SATNET, all using TCP. Afterward, Cerf, Jon Postel, and Danny Cohen suggested a small but important change: They should take out all the routing information and put it into a new protocol, called the Internet Protocol (IP). All the remaining stuff, like breaking and reassembling messages, detecting errors, and retransmission, would stay in TCP. Thus, in 1978, the protocol officially became known as, and was forever thereafter, TCP/IP.

Every message ever sent on the web is done with TCP/IP. More than nearly anything else, it is the defining protocol of the Internet that is everywhere today.