The keyboard has many keys divided into areas like alphabet, function, numeric, and arrow keys. The most common layout is QWERTY, named after its first six letters. Keyboards are used to enter data, and skilled typists can type very fast. Overuse can cause repetitive strain injury (RSI). Pointing devices like mice are also common input devices, starting with mechanical mice using rubber balls and now optical and cordless mice. Touchpads are for laptops in small spaces. Digital cameras store photos on memory cards instead of film. Barcode readers use lasers to read product information codes. Joysticks contain buttons and allow fast interactions for games. Output devices like printers provide a hard copy and come in types