The data that a computer receives is input, the first part of the machine processing cycle. Input can be raw data, user responses like mouse clicks, commands, and programs.
The keyboard is an input device that comes is several different shapes, sizes, and key arrangements. The QWERTY layout is still the most popular, though it is not the most efficient layout.
A variety of pointing devices let you control the computer - mouse, trackball, game controller, glide pad, pen or stylus, touchscreen.
Modern terminals like point-of-sale terminals make it easy to input sales, calculate totals with tax, and monitor inventory.
Multimedia input devices send photos, sounds, and videos to your computer. You can even use your voice to control the computer or input data, if you have voice recognition software.
Automating input helps avoid errors. Scan instead of type! Special inks, special shapes to characters, bar codes of several types, and RFID tags all make it easy to input accurately. But some errors can still occur. Transcription errors record an incorrect character. Transposition errors reverse the order of characters. Input must be checked for correct type of values, reasonableness, and consistency.