Tablet PC: the writing's on the screen

At the end of this year, yet another Microsoft-powered mobile PC device hits the market: the Tablet PC. The device is A4-sized, and uses the screen as the primary input mode.

"One of the big things that is going to lead PC development in the next decade will be the advance of handwriting recognition and pen-driven computing, a concept we are calling natural computing," explained Alexandra Loeb, vice president for Tablet PC at Microsoft.

Unlike handheld devices that run Microsoft's Pocket PC 2002 operating system, Tablet PCs do not feature a touch screen that responds to surface impact.

Between the plastic fascia and the TFT panel is a serial digitiser, as found in most graphics tablets. It is used with a special active stylus containing a proximity sensor, and is capable of sampling the pen's movement across the screen far faster than a normal touch screen. This eliminates much of the jagged, square-edged character of PDA displays.

"There have been significant advances in display technology, reducing the eye fatigue normally associated with reading on screens," said Loeb.

Software in the operating system also intercepts the handwriting input, re-rendering the edges to produce smoother curves.

Tablet PC will be backed by only one application, Windows Journal. This emulates paper, acting as a doodle pad and allowing users to write and draw freehand.

Individual sections can be re-sized, and you can also cut, copy and paste, and apply basic text tools such as bold and italic type. Other tools include a highlighter pen.

These tools will be retro-fitted into Microsoft Office with a toolbar patch once the Tablet PC is launched. Users will be able to write in Office documents and Outlook emails in the same way as they can with Journal, as well as annotate and highlight documents.

The device offers handwriting recognition support, but there is no scope for training the handwriting recognition. This could prove problematic in market sectors such as healthcare, where poor handwriting and personalised shorthand are common.

There are also issues with screen calibration and it is not certain that these will be resolved by the time the product is released. Recognition of the pen suffers from a slight offset to the position of the nib on the screen. It is satisfactory for writing, but hampers fine control of Windows functions such as scroll bars.

Development of the Tablet PC is well advanced, and hardware manufacturers such as Acer, Viewsonic, FIC, Hewlett Packard and Fujitsu Siemens have already committed to making tablet-only devices or tablet/laptop hybrids.

The beta version is encouraging, but the lack of trained handwriting recognition will be a significant barrier to early adoption, particularly in the corporate sector which is more used to PDAs that can be personalised to the writing idiosyncrasies of the user.