Techarp, apparently drawing on information from computer manufacturers, says there will be starter editions designed for two categories, a netbook and a small notebook PC, as well as a special edition for China. Microsft defines a netbook as having a screen diagonal of 10.2in or less.

Techarp says limitations on graphics and touch capabilities on netbooks have been removed.

Microsoft is keeping mum on the subject but with at least three open-source projects - Android, Intel's Moblin and Ubuntu - targeting the new formats it must be wary of allowing its rivals to gain critical mass in a potentially huge new market.

The fixation on categories - netbook and small notebook - has more to do with software pricing than technology. The cheaper the hardware gets, the higher the software costs as a proportion of the selling price, and the more likely it will be that people will choose open-source if Microsoft does not cut its prices. Hence the idea of a Windows 7 Lite, which allows the company to undercut its own products on price.

Microsoft has no option but it's a risky strategy, especially as people may have different expectations of emerging true portables and don't necessarily want a "pocket Windows". This is especially so as first generation non-x86 formats  are likely have the edge over Wintel products on portability and battery life (see below). 

Apple, which broke one mould with the iPhone but has so far ignored the new formats, could also spring a surprise; but it is not chief executive Steve Jobs's style to go downmarket and any Macnetbook is unlikely to be challenging on price.

Meanwhile, Lenovo has launched a 12.1in machine using nVidia's Ion platform, which couples a GeForce 9400M graphics processor and Intel Atom processor on a Pico-ITXe motherboard.  Ion gives the IdeaPad S12 (pictured above left) the performance of a gaming machine capable of playing HD movies to an external display using an HDMI link. It is described as a netbook, contrary to Microsoft's definition, which just goes to show that where the marketing men lead, the public is not always sure to follow.

This evolution of what will surely be the iconic platform of the early 21st century still has years to run but we are at last beginning to get the technology that will allow it to happen, notably powerful frugal processors and systems-on-a-chip (SoCs). These have already given us ultra-portable netbooks and over the next few months we should see the release of a number of devices in a still smaller category Intel has called the Mobile Internet Devices, or MIDs.

Vendors including Intel have tended to talk down the capabilities of these true portables, fearful both of undercutting the value of their own larger machines and of raising people's expectations too far. But remember that even a low-powered device with a relatively slow Wifi link can use harness full PC power by acting as a front-end for a machine on the network. And very-low-drain SoCs, whether ARM or Intel  based, are perfectly capable of running office apps.

The constraints are thus more ergonomic than technological. But while people may end up using these pocketable devices as workhorses, particularly if the input problem is cracked (which is a subject in itself), the exact way they will be used is almost impossible to predict.

One certainty is that they will act as a content delivery platform, more usable than today's iPhone and iPod Touch. This will be a major cultural change, creating incidentally a new communications medium with elements of the website, newspapers, magazines and TV. Computing, arguably, is at the start of the most important transition since low-cost mainframe power hit the desktop.

E-book readers are the easiest category to fit this format because their bistable displays use power only when changing state. This means batteries can be smaller and last longer, and no heavy cooling is required. And the Cool-er has no wireless, which would save a little weight.

But it shows what is possible: an electronic notebook the size of a paper one. Time will tell whether this will become the dominant size for ultra-mobiles, even the dominant computing platform. For sure it raises the question of what the smallest practical size for a working platform is.