Sony has unveiled the first model in a new line of notebook computers, the Vaio VX series, and lifted the veil on a couple of prototypes the company is currently developing, among them a strong contender for the title of smallest Windows XP-based notebook in the world.

Few details were available about the petite notebook, called the Vaio-U (pictured) and Sony would not disclose specifications for the prototype model or remove it from a display case.

The machine is noticeably smaller than most Windows-based notebooks currently on the market. Its size and black plastic case gave the machine more than a passing resemblance to Sony's Vaio-GT machine, a 6.4in LCD (liquid crystal display) equipped notebook, although the Vaio-U prototype lacked the digital still camera that makes the Vaio-GT so distinctive.

A pointing device and buttons have been built into the notebook above the keyboard so they can be easily operated when the machine is held on either side and the keyboard overlay revealed another possible clue as to a feature on the machine.

In the same way that keys on the righthand side of a notebook keyboard are labelled so they can serve double duty as a numeric keypad, the keys on the lefthand side of the machine were labelled like a telephone keypad (for example, 2 ABC, 3 DEF and so on).

The machine is still in development and, as such, no information on the launch schedule or pricing was available.

Also on show at the Tokyo news conference was a version of Sony's already launched Vaio-C1 notebook. The machine was running Sony's GigaPocket software, an application that allows a personal computer to be used as a hard disk video recorder.

Previously available only on Sony's desktop line of machines, the company said it is now working on putting the software into notebook computers to allow people who don't have room for a desktop machine — or don't want one — to enjoy the same function.