Basic Parts of A Computer System

By Doug Wetzel

Whether you operate a personal computer (PC) or a Macintosh, a server or a desktop computer, a PDA or a Notebook, they all contain and use the same basic computer parts to function. These parts are known as hardware because they consist of tangible, or hard, physical components.

Input devices

Computers receive information through "input," and the primary input devices are the keyboard and mouse. Other input devices include gaming joysticks, biometric pads and special, handicap-accessible devices, such as control pedals and keyboard wands.

Computer monitor

The main way to receive information from a computer is through its monitor. The monitor is a television-like device that can display text, images and video. Monitor types include flat screen Liquid Crystal Display (or LCD) monitors and the older and less common Cathode Ray Tube (or CRT) monitors. It also is possible to connect a computer directly to a television, enabling its display to be seen on large-screen and projected-TV formats.


The majority of parts making up a functional computer connect, directly or indirectly, to an electronic circuit board is known as the motherboard. The make and model of the board determines the types and numbers of components that may be connected as a single computer.

Central processing unit

All computers compute, and they accomplish this by processing data -- either received as input or in preparation for output. The hardware handling the majority of this workload is known as the Central Processing Unit, or CPU. It consists of one or more processing chips; the type of CPU a computer may use is limited by its motherboard.

Random Access Memory

As a computer operates, it needs a place to store and retrieve data. In other words, it needs "memory," just as people do. A computer's fastest memory -- and one entirely temporary -- is found in storage chips known as Random Access Memory, or RAM.

Hard-disc drive

While RAM is very quick, data stored there is lost when the computer is shut down or restarted. Obviously, some data needs to be stored for long-term access, and the primary hardware used to store this data is the hard-disc drive. Hard drives, while able to store data for long periods, are notably slower at storing and retrieving data than RAM.

CD/DVD drive

Another method of storing data for the long-term is accomplished by writing data to a compact disc (CD) or DVD (digital video disc). A CD or DVD drive is used to read, and sometimes write, to these discs. These discs have the additional advantage of mobility, as they can be easily carried to another computer for use.

Floppy drive

An older type of disc drive is the floppy drive. It is referred to as a "floppy" because the discs it reads and writes are somewhat flimsy and flexible. While a floppy drive has many of the same benefits as a CD or DVD drive, its discs usually hold a much smaller amount of data and, worse, are more easily damaged.

Power supply

A computer's power supply unit, or PSU, provides and regulates the electricity needed by the other components to operate. The strength or overall output capacity of a PSU is measured in watts. Most computers use between 300 and 500 watts, though some may require two or three times that amount to operate properly.

Expansion cards

Most motherboards provide one or more expansion slots. In each slot, an appropriate expansion card can be added to increase the functionality of a specific computer. Examples include graphic cards, network cards and sound cards.

Additional ports

A computer port is a small receptor through which additional (or peripheral) external devices can be connected to the computer. Popular examples include serial, parallel and Universal Serial Bus (or USB) ports.