Computers.

2. A video camera that feeds its images in real time to a computer network.
5. A pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball.
9. A portable, usually battery-powered microcomputer.
11. A computer input device for controlling the pointer on a display screen by sliding the finger along a touch-sensitive surface.
12. Senses the user pressing directly on the display.
14. A device for projecting a beam of light.
19. A global system of interconnected computer networks.
20. The components of the computer in which such information is stored.

1. A combination of two or more cells electrically connected to work together to produce electric energy.
3. A pair of small loudspeakers which are designed to be held in place close to a user's ears.
4. A set of keys used to input information to a computer.
6. Also called processor.
7. A segment of self-replicating code planted illegally in a computer program, often to damage a system.
8. A thin, flexible plastic disk coated with magnetic material, on which data can be stored for later use.
10. An acoustic sensor that provides input by converting sound into electrical signals.
13. An output device that produces a paper copy of alphanumeric or graphic data.
15. A lever used to control movement of a cursor or other graphic element for video games.
16. A component, as a CRT, with a screen for viewing data at a computer terminal.
17. An electromechanical device which produces sound.
18. A palm-sized, button-operated pointing device.