ABSTRACT
Input devices are those portions of computer, data processing, and information systems that perform the essential function of providing some means for entering commands and data into the system. Keyboards are essentially electromechanical devices, and are ubiquitous, in spite of the inroads of other input devices. The light pen initially was a very popular means for accomplishing manual input to the random deflection information display systems, but fell out of favor when raster systems became more popular due to its being somewhat difficult to use with raster systems. The movable element can be the same as used in the mouse, and the output can be a set of bits corresponding to the coordinates to which the cursor should be driven, or where the command should be carried out. Touch input devices come in two basic forms, either placed directly on the display surface, or as a separate panel attached to the computer system.
