Forty years ago today, the first message was sent over the Internet. And forty years ago today, somebody’s internet connection went down for the first time.

The Internet as we know it has its origins in the Advanced Research Projects Agency, an American group set up in the late 1950s as part of the technology race against the USSR. A decade later, the agency went ahead with plans to build a network of computers to make it easier and quicker to share software and test results across different universities.

The system they chose was remarkably similar to the way most people access the net today. The different computers at each site connected via modem to a dedicated machine known as an interface message processor: that is to say, a router. The IMP at each site connected directly to a telephone line (though this was a leased line rather than a standard domestic connection), passing data to other sites as well as receiving data and routing it to the appropriate machine. Data was broken down into packets and then reassembled at the other end. (See Charlie & The Chocolate Factory’s Mike Teevee for a full technical explanation.)

The initial network linked up four sites: UCLA, the Stanford Research Institute (SRI) and UC Santa Barbara (all in California) plus the University of Utah. On October 29 1969, a student programmer from UCLA, Charley Kline sent the first message on ARPANET, to be received at a machine at SRI. What he recorded as talking “host to host” is what we would call the first internet data transfer.

Unfortunately the connection dropped mid-transfer and the message which came through simply read “Lo”. Had Kline called it a night there, we would be left with the wonderful image that he might have intended to deliver the world’s first LoL, or perhaps even entertain the staff of SRI with an amusing ASCII-based picture of his cat yawning.

Instead, around an hour later, he got through and ended the mystery by delivering the message “Login.”