Compaq has come out of the closet as one of the first PC makers to build Microsoft's Tablet PC, an Etch-a-Sketch look-alike which uses the Windows XP, son of Windows, operating system codenamed Whistler.

Microsoft's chairman, Bill Gates, showed off a prototype of the Tablet PC at a computer show in Las Vegas last November, but you won't be able to buy one until next year.

The Tablet will be A4 sized and people will be able to use it like a pad of paper, taking notes and reading documents with it. It should weigh less than current notebooks, a Compaq spokesman said, although it will retain the power of a fully fledged PC and run standard Windows applications.

Windows XP, which should be ready by the end of this year, is expected to appeal to consumers who want facilities such as handwriting recognition.