It has often been said that change is the only constant in the 21st Century.

And there is little doubt that the restless tone of these times is something that the web has helped to accelerate.

But the only reason that the net and the web can cope with that punishing pace is thanks to work done four decades ago by British mathematician Donald Davies at the UK''''s National Physical Laboratory (NPL).

On 5 August 1968 Dr Davies gave the first public presentation of work he had been doing on a method of moving data around computer networks called "packet switching".

The idea may sound mundane but, said John Pethica, chief science advisor at the NPL, the modern world would be a lot slower without it.

The internet, mobile phone networks and fixed line phones now all use the principles Davies and his team established to cram as much data as they can down the cables and wires making up the world''''s telecommunication networks.

Clogged pipes

Dr Pethica said the urge to find a better way to handle data emerged when computer networks were almost unheard of. 
Donald Davies found a way to help networks route data efficiently

At that time making a phone call involved creating a dedicated circuit between the handset of a caller and the person they wanted to chat to.

"A lot of people realised that point-to-point was going to be a big problem, even for telephones even before they thought about computers," said Dr Pethica. "The problem was how you turn it away from that."

The problem with human speech is that most of it is made up of silence - be that the pauses between words, time taken to breathe or gaps when one person waits for another to speak.

Using most of a telephone network to transmit silence is not a very efficient use of that resource. Far better would be to find a way to fill the blank spots with the moments from others calls when those folk were speaking.

Dr Pethica said many in the computer world in the late 60s were thinking about how to solve this problem.

"There were other ideas around, like Paul Baran at Rand, but they were nowhere near as useful as what Donald Davies did in terms of size of packets and nodes," said Dr Pethica.

"It was Donald who had the idea of making a set of nodes that you send packets of data to that find their own way through," said Dr Pethica.

The insight of Dr Davies and his team was to slice data, be that a chat on the phone, an e-mail or a picture, into separate pieces or packets. These are then put on the network and rely on the intelligence of nodes in the network to help them wend their way to their destination. Once there they are re-assembled into the right order.

From BBC News.