Input and output peripherals

Main article: Input device

Input devices allow the user to enter information into the system, or control its operation. Very early computer systems had literal toggle switches that could be tested by running programs as a simple form of user input; modern personal computers have alphanumeric keyboards and pointing devices to allow the user to interact with running software.

• Text input devices
  • Keyboard - a device to input text and characters by depressing buttons (referred to as keys or buttons).
• Pointing devices
  • Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
    • Optical Mouse - uses light (laser technology) to determine mouse motion.
  • Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
  • Touchscreen - senses the user pressing directly on the monitor.