An electronic kiosk (or computer kiosk or interactive kiosk) houses a computer terminal that often employs custom kiosk software designed to function flawlessly while preventing users from accessing system functions. Indeed, kiosk mode describes such a mode of software operation. Computerized kiosks may store data locally, or retrieve it from a computer network. Some computer kiosks provide a free, informational public service, while others serve a commercial purpose (see mall kiosk). Touchscreens, trackballs, computer keyboards, and pushbuttons are all typical input devices for interactive computer kiosk.