IF YOU find being buried under the mice, keyboards and all the other computer paraphernalia a little cumbersome then take heart, because you are not alone. Irritated by a clutter of similar electronic gadgets an his desk, a researcher at the Tokyo-based Sony Computer Laboratories devised a quick and easy way to move files from one computer to another without ever having to touch a mouse or a keyboard. Instead, he uses a pen-like device to 'shift' a file icon off one computer screen and transfer it to another. The file itself is then automatically transferred between the two computers over a network.

"I first thought of this when I was using three computers on my desk at the same time," says researchers Jun Rekimoto. "There were three different mice on the desk and I kept getting confused as to which mouse went with which computer." The answer he has come up with, called pick-and-drop technology, is designed for a future generation of computers that will use the interactive screens now common in palmtop computers, which allow users to write on them with a pressure sensitive pen.

The pen-and-screen combination used by Sony is a commercial product made by the Japanese company Wacom. Behind the screen is a low-power radio transmitter linked to a microprocessor. As the pen approaches the screen, a coil inside it interferes with the transmitted signal. By working out where the interference is coming from, the microprocessor works out the position of the pen on the screen. However, the pen is also identifiable: buttons on its side can be pushed to alter the length of the coil and its interference pattern, which changes its identity (ID).

In Sony's system, tapping the pen onto a file icon links the pen's ID code to the file. Then, when the pen is tapped against the screen of another computer on the same network, the network's server notes the pen's ID code, checks which file it touched last and transfers that file to the new computer. Files can also be copied or cut and pasted this way (New Scientist, Vol 160, No 216 1).

The system should be especially useful for people such as those in stock market trading and television editing, who regularly have to use two or more computers. Rekimoto, however, says pick-and-drop could prove its worth in any other office where people need to exchange files frequently and also for people preparing lectures and presentations. A speaker could connect his/her laptop computer to a large interactive display screen, known as a digital white-board, and transfer data such as text, video clips from it to the whiteboard with the touch of the pen. Sony's prototype has been developed on Mitsubishi palmtop computers, which are equipped with Wacom's interactive liquid crystal display (LCD) screens. The company admits it is not ready to commercialise the idea. "A lot of decisions have to be made about an application for the technology," says Sony spokesperson Daniel Lintz. "It takes time to transfer these kinds of technologies to the development stage."

As part of the development process, Sony wants to increase the number of different pen ID codes - there are just three at present - to make the system practical for a large number of users on the same network.