If Sony's recently launched Vaio W computer was a song, it would shot in at number one with a bullet.

As it is, the new computer, a desktop machine that tries to compete with the laptops for size, has been sitting pretty at the top of Japan's PC sales chart for a month now.

Such is the demand that getting one is proving to be a major headache for consumers. The success of the product proved a surprise for Sony, which sold in a single day what it had expected to sell during the first month.

According to sources, Sony Japan has been receiving requests from it's European sister company to ship the units in Europe. Exactly when this may happen isn't known, but it seems highly likely it will.

The success of more portable, laptop-like systems is in line with recent numbers released by the European Information Technology Observatory, showing how the attraction of the traditional grey or beige box PC is in serious decline.

Behind the Vaio W's success are its form factor, functions and surprising price.

The company began work on the machine after market research showed that, while more than half of Japanese consumers were buying laptop computers, they were not buying them for mobility but because they took up a small amount of space — an important consideration in the type of one-room or two-room apartment in which young Japanese typically live.

Figures from IDC Japan for the fourth quarter of 2001 estimate 58 percent of all consumer PC sales in Japan during the period were laptops — around double that of most other countries. Japan has historically been ahead of the times in terms of PC sales.

When not in use, the Vaio W takes up less space on a desk than a notebook computer. This is thanks to a keyboard that folds up to cover the lower half of the display when it is not needed. Sensing this action, the PC will automatically shut itself down and a software clock will appear in the half of the display that is not covered. The main body of the machine is also built into a case behind the monitor, and the screen can be pushed to a vertical position when not in use, further saving desktop space.