A mobile device (also known as converged device, handheld device, handheld computer, "Palmtop" or simply 'handheld) is a pocket-sized computing device, typically comprising a small visual display screen for user output and a miniature keyboard or touch screen for user input. In the case of the personal digital assistant (PDA) the input and output are combined into a touch-screen interface. Smartphones and PDAs are popular amongst those who require the assistance and convenience of a conventional computer, in environments where carrying one would not be practical
Palmtops are a class of personal computers (generally with PDA software) that fit in the palm of your hand One of the most well-known palmtops is the Pilot, developed by PalmOS and marketed by US Robotics
A computer small enough to fit in the user's hand Primarily used as personal organisers, they provide users with the ability to store names and addresses, play games, access the Internet, and use a calculator
A pocket computer with a calculator-style keyboard or stylus input (for small size) Will run a small set of dedicated applications an probably expects to be connected to a desktop PC from time to time to upload or download material that requires a full keyboard etc
A computer small enough to hold in one hand and operate with the other Palmtops may have specialized keyboards or keypads for data entry applications or have small QWERTY keyboards Its capabilities are similar to a PDA