[This was posted on the BBC site at the end of October]
It is forty years to the week since the first data packets were sent over the ARPANET, the research network commissioned by the US Department of Defense Advanced Research Projects Agency (ARPA) to see whether computer-to-computer communications could be made faster, more reliable and more robust by using the novel technique of packet switching instead of the more conventional circuit switched networks of the day.
Instead of connecting computers rather as telephone exchanges work, using switches to set up an electric circuit over which data could be sent, packet switching breaks a message into chunks and sends each chunk – or packet – separately, reassembling them at the receiving end.