Scientists at IBM have completed work that may make it possible to do away with the copper wires used to couple processing cores to each other.

The connector created by the team uses light to pass data between the computational cores that is faster and uses less power than copper wires.

The device is smaller than previously demonstrated connectors promising to shrink future computational clusters.

The IBM development, reported in the journal Optics Express, could replace the copper wires that connect cores with a device that converts electrical signals to pulses of light.

The device, called a silicon Mach-Zehnder electro-optic modulator, is many times smaller than previously produced convertors.

"What we have done is a significant step toward building a vastly smaller and more power-efficient way to connect those cores, in a way nobody has done before," said Dr Tze-chiang Chen, a spokesman for IBM's science and technology research division.

It could also boost the power of coupled computational cores because by using light, the speed at which data travels between the cores would be accelerated.

With light the researchers, led by Dr Will Green, can cut the amount of power needed to move data between processors and slash the amount of heat a large computational cluster produces.

The technology, which can transfer data up to a distance of a few centimetres, is about 100 times faster than wires and consumes one-tenth as much power, said Dr Green.

The lower power requirement should reduce operational costs for supercomputers.

Doing away with some of the cooling systems for computational clusters could shrink the systems further.

So far the team has only demonstrated the technology in a lab and it could be years before it makes its way into commercial chips.

Kill switch' dropped from Vista

Microsoft is to withdraw an anti-piracy tool from Windows Vista, which disables the operating system when invoked, following customer complaints.

The so-called "kill switch" is designed to prevent users with illegal copies of Vista from using certain features.

But the tool has suffered from glitches since it was introduced with many Windows users claiming that legal copies of Vista had been disabled.

Microsoft says its efforts have seen a drop in piracy of its software.

In a statement released by the company, Microsoft corporate vice president Mike Sievert, said: "Users whose systems are identified as counterfeit will be presented with clear and recurring notices about the status of their system and how to get genuine copies."

'Take action'

"They won't lose access to functionality or features, but it will be very clear to them that their copy of Window Vista is not genuine and they need to take action."

Microsoft has described the new approach as a "change of tactics". It said efforts to tackle piracy had seen numbers of fake copies of Vista at half the level of XP, the previous Windows operating system.

The change will take effect with the release of Service Pack 1, a major update to Windows Vista.

Customers who buy a copy of Windows Vista or have the operating system (OS) installed when they buy a new PC are required to validate the OS with Microsoft.

An online tool, called Windows Genuine Advantage, checks the authenticity of the OS to determine if it was legally acquired.

The tool can "lock" Vista from further use if it believes it is an unauthorised copy. But many users have complained that the system is not working because legally bought copies result in error messages.

It was introduced in 2006 as a voluntary option, but became mandatory with the release of Vista, and had problems from the day it was introduced. Mr Sievert added: "It's worth re-emphasising that our fundamental st