1. Hardware Components Controller cards Bus Lines Ports Power Supply Secondary Storage

2. 1.Controller cards On the motherboard there a number of connectors called expansion slots These allow the installation of controller cards for functions such as graphics, audio, co- processor, printers, interface and modems Controller cards are becoming less common as the chips are now installed directly on the motherboard

3. 2.Ports Ports are connectors on the computer that allow the connection of external devices such as keyboards, mouse, display Ports are either serial or parallel. Serial transmits data 1 bit at time along a wire, whereas parallel transmits many bit at a time along multiple wires The latest port technology is USB (Universal serial bus) which allows the connection of 127 devices to one USB port and allows ‘hot-swapping’ (detection and loading of devices without a re-boot

4. 3.Power Supply A small box in the back of the computer that provides power for all the components. The power supply usually is provided with a fan The power supply provides +12V, -12V and 5V power sources

5. 4.Secondary Storage Hard disk drives that are coated with a magnetic material CDROMS and DVD that use a laser the write and read to and from reflective surfaces Classwork: Comparing Hardware Systems (handout) Due 9/2/2011