Flash of inspiration

In 2005, when Nicholas Negroponte — founder of MIT’s Media Lab — announced his intention to bring out a low-cost laptop for the developing world he was greeted by a chorus of corporate derision.

Two years on, the mean-spirited sniping has given way to admiration (or in Intel’s case imitation) and Negroponte’s not-for-profit organisation One Laptop Per Child (OLPC) is gearing up for mass production of a device that promises to pass on the educative fruits of the IT revolution to the schoolchildren of the developing world. Negroponte and his team are now finalising plans to sell the XO — or $100 laptop as it has been dubbed — in large numbers to governments across the developing world.

According to OLPC’s technical director, Mary Lou Jepsen, the XO has arrived at this promising position courtesy of a design that makes it cheap to produce and operate, while retaining the performance characteristics of far more expensive devices.

Running on an open-source Linux operating system, the machine uses flash memory in place of a hard drive. It has a specially-developed low-power display screen that can be read in the sunlight, a 10-hour battery life, and consumes so little power that it can be charged by hand.

What’s more, separate computers are able to connect to each other via a built-in wireless feature dubbed Mesh networking. As well as enabling laptops to talk to each other, this also allows multiple laptops to piggyback on another computer’s internet connection.

The cost of the machine is around $175 (around £90). It is expected to fall to the $100 mark by 2009, and Jepsen believes that this could ultimately fall to $50. One of the keys to getting the cost so low has, she said, been the group’s development of a new type of display screen. ‘The average cost of a display in a laptop is $120 so that’s a real barrier to a $100 laptop.’

Low-cost wi-fi chips, less than five dollars worth of plastic, and a camera that costs just one dollar have also helped force the manufacturing cost down. but perhaps one of the biggest factors was the decision to do away with a hard disk and replace it with flash memory. ‘Hard disks are expensive, power hungry and the leading cause of hardware failure,’ said Jepsen. ‘So we got rid of it and moved to flash. Thanks to the ipod revolution the cost of flash has plummeted 50 per cent every year and it seems to keep going.’

It is notable, she claimed, that all of these cost reductions have been achieved in the development of a high-quality product that is fast attaining design icon status. Indeed, the XO recently went on display at New York’s museum of modern art.

Jepsen, who formerly headed Intel’s display division, explained that she managed to get the screen cost down to about a third of an average one by re-thinking the pixel layout to match the function of the human vision system. This borrows from TV and the way that an mpeg is encoded, where there is three or four times the black and white (luminance) resolution compared to the colour (chrominance). She said that this has enabled the team to produce a display that is both low power and readable outside.