pen-based computer, computer that uses pattern-recognition software to enable it to accept handwriting as a form of input. A stylus, which may contain special electronic circuitry, is used to write on the computer display or on a separate tablet. The earliest devices were limited to recognizing geometric shapes for computer graphics applications and neatly printed alphabetic characters. Pattern recognition has improved to the level where cursive input is now acceptable, especially in personal digital assistants, although such input is not always accurately interpreted by the software. Some software requires the use of a specially modified alphabet to enter data.