A pared down "computer" to replace bulky, grey desktop PCs could help close global digital inequalities. Not-for-profit developers, Ndiyo - the Swahili word for "yes" - said it could open up the potential of computing to two billion more people. The sub-£100 box, called Nivo, runs on open-source software and is known as a "thin client". Several can be linked up to a central "brain", or server.

Thin clients are not new, but advances have made them more user-friendly. They have been employed in large organisations in the past, but the Ndiyo project is about "ultra-thin client" networking.It said the small, cheap boxes were targeted at smaller companies, cybercafes, or schools, which need an affordable, reliable system for providing clusters of two to 20 workstations."Your PC is a bulky, noisy, expensive mess that clutters up your life," Ndiyo's Dr Seb Wills told a Microsoft Research conference in Cambridge, UK.

"Our emphasis and core motivation is the developing world for whom the current 'one user, one PC' approach will never be affordable," he told the BBC News website. "But we think our approach is also of benefit to organisations in the developed world who don't want to throw away money on buying and maintaining a full PC for each user."Desktop machines with which we are familiar, are inflexible, and power-hungry, according to Ndiyo.

The raw materials used for a PC are 11 to 12 times the weight of the machine, he explained.Typical office workstation set-ups also use more power than thin clienting. A PC typically uses 100W of power, whereas Nivo uses five. In some developing countries, buying a desktop computer is the equivalent to the price of a house, explained Dr Wills, making it difficult for people to take advantage of what computing technology can offer. "Nowadays, PCs are about communication than anything else," he said. "We have the potential to rethink the way we could do this stuff," he added.

The boxes would not be able to handle graphics-intensive multimedia content currently, but that will change as ethernet bitrates improve to handle more data. About 50% of the UK's workforce work in organisations with fewer than 50 employees, according to Ndiyo. Currently, each employee might have his or her own desktop machine, connected to the company network through ethernet connections, with software licences for each workstation. Licences for software are often a significant part of expenditure for smaller companies which rely on computers.

But a recent UK government study, yet to be formally published, has shown that open source software can significantly reduce school budgets dedicated to computing set-ups. Many organisations replace PCs every three years and also require technical support when something goes wrong. Thin clients using open source software can mean these expenses are bypassed. Since August 2004, Ndiyo has had a group of Java developers running large applications to test out the robustness of the system.

The small Nivo box, developed along with a commercial partner, Newnham Research in Cambridge, is essentially a computer - known as the "client" - which largely depends on the central server for processing activities. Applications, for instance, are kept on the main server and accessed through the Nivo box. The Nivo unit itself measures around 12 by eight by two centimetres. It has no moving parts, but it has ports for ethernet, power, keyboard, mouse and a monitor.

It comes with two megabytes of RAM. The next version currently under development will have a USB port, soundcard, local storage capacity, and will be even smaller.

"Essentially, it is about sending pixels over the net," explained Dr Wills.

"With modern ethernet connections, you can get enough performance by sending through compressed pixels."

A typical cybercafe set-up, Dr Wills explained, would involve 20 Nivo boxes, a gigabit switch, and a single 2Ghz, 2Gb RAM server.

The not-for-profit origination is also working on the idea of using the Nivo box for "plug and play" clustering.

Ultimately, Ndiyo hopes that the box can shrink down to a single chip and introduce wireless ethernet connections.

"The vision is that the monitor will have an ethernet port which requires less electronics than the standard VGA monitor," said Dr Wills.

Open source software is used in many developing country computer initiatives. There are other attempts at providing cheap alternatives to desktop PCs for developing countries, such as the Simputer. This is a cheap handheld computer designed by Indian scientists. (However sales of the Simputer have been less than impressive and its African distributor closed down last year).