Computers organize business information, manage household budgets, provide entertainment and fun, and connect us with the world. In short, modern life would be unimaginable without these technological marvels. However, the computer is not just a single device, but a system of different parts.
The computer case is what we normally think of when they talk about a computer. This box contains, at minimum, the CPU (Central Processing Unit), a collection of electronic circuits that act as the brain. It can also house RAM (Random Access Memory), which stores temporary information as you operate the computer.
The hard drive is a long-term storage device that preserves information on a disk even when the computer is turned off. Though typically stored within the system box, a hard drive can also be external and attached via cable. The cost of hard drives are constantly dropping, making it cheaper to buy a system with less capacity, and then to expand storage by buying drives later.
Input devices let you enter information into the system. Common examples include a keyboard, for entering text, and a mouse, for moving and activating icons in a graphical environment. Other devices include: for multimedia, a webcam for captures of still and moving images, and a microphone for transmitting audio communications.
CD and DVD drives are typically built into the system box, and allow the transfer of information through the use of hard media. CDs typically play music while DVDs play videos. However, both types store files and documents, since the typical drive cannot only retrieve data, but record it as well.
A monitor is how we receive information in a visual form, which can consist of text, images and video. Though these display devices used to consist of bulky CRTs (Cathode Ray Tubes), they now appear as compact, energy-saving LCDs (Liquid Crystal Displays). This external device is controlled by video card, which is located inside the system box.
Speakers deliver audio information such as music from CDs, sound from games or voice from Internet chat. Though they may be built into the box or monitor, the best ones typically stand alone and may consist of an amplifier, multiple speakers and a subwoofer. They require an audio card that is located inside the system box.
A printer produces hard copy versions of computer information in color, and black and white. This information can consist of text from word-processing documents, photographs from digital cameras or artwork from graphics programs. Inkjet printers are initially cheap, but use expensive inks. Laser printers are faster and initially expensive, but their long-lasting cartridges produce cheaper printouts.