"One of the most common complaints about PDAs is their limited screen size. Most offer a display of 5 by 3 inches or less--an inevitable restriction given the need to hold them in a single hand.

"With the advent of wireless, PDAs could be very useful for Web browsing, but they're always constrained by the small screen," said John Karidis, a distinguished engineer at IBM. Karidis is part of a research team at IBM's laboratories in Hawthorne, NY working on prototypes for new PDA systems.

One of the more promising designs uses a dual screen, connected by a single hinge, which provides a total display area closer to that used on desktop PCs when the device is unfolded. As with most PDAs, data is entered by touching the screen with a stylus, If larger amounts of input are required, an on-screen keyboard could be used, Karidis said."