All of the data processing and storage happens inside the computer. A typical computer consists of a motherboard, CPU, memory, hard drive, optical drive, power supply, and a case to hold everything. Peripherals such as keyboards, mice, monitors, printers, etc. attach to the computer, usually by wires plugged into the ports on the back of the computer. Together, the computer and all of the devices attached to it make up the computer system.

The computer pictured below is called a mid-tower desktop computer. The term "desktop computer" is a holdover from the early days of PCs when most PCs were wide and short and actually sat on a user's desk under the monitor. True desktop computers are still available but most people buy desktops like this one and set it under their desk. In common usage today, a desktop computer is any computer that isn't a laptop, regardless of whether it actually sits on your desk or not.

The computer is also sometimes called the system unit. Incorrect terms for a computer include: CPU, hard drive, or brain. Calling a computer a CPU or hard drive is like calling a car an engine or a wheel.

Dell Dimension Desktop Computer	Side panel removed
Looking inside at the motherboard and components	Back of computer showing external ports

Below is how the basic parts of a computer look without the case

Motherboard with nothing attached.

Motherboard with CPU and two cards installed.

Motherboard seen from the other side with the hard drive attached

Finally, all wrapped up as you'd normally see it. The computer's motherboard and power supply are very similar to the ones pictured above. This computer also has two more expansion cards installed between the video card and Ethernet card

Return to the main Computer Hardware page for more information about individual components