A computer case (also known as the computer chassis, box or housing) is the enclosure that contains the main components of a computer. Cases are usually contructed from steel, aluminum or plastic although other materials (such as wood and perspex) have also been used in case designs.

Size and Shape of Computer Cases

Cases can come in many different sizes or "form factors". The most common form factor is ATX, although small form factor cases are becoming popular for a variety of different uses.

Cases are often said to come in "towers" (such as mini tower, mid-sized tower and full-sized tower)", "desktops", "pizza boxes" (also called flatbed or (horizontal) and "slim desktops" that uses the LCD like housing. Tower cases are taller and typically have more room while desktop cases are more compact and are more popular in business environments.

Small form factor cases are a variety of cases that are coming more and more common. Companies like Shuttle computers and AOpen have been producing such cases and Mini-ITX is the most common motherboard designed for these cases. Apple Computer recently announced its Mac Mini computer, which is around the size of a CD-ROM drive.

Computer Case Functions

Cases usually come with room for a power supply unit, several expansion slots and expansion bays, wires for powering up a computer and some with built in I/O ports that must be connected to a motherboard.

Motherboards are screwed to the bottom of the case, its I/O ports being exposed on the side of the case. Usually the power supply unit is at the top of the case attathed with several screws. The typical case has four 5.25" and three 3.5" expansion bays for devices such as hard drives, floppy disk drives and CD-ROMS. A power button (and sometimes a reset button that can be turned-on and off using a remote control) are usually located on the front to turn the computer. LED status lights for power, hard drive activities are often located near the power button which are powered from wires that connect up to the motherboard. Some cases come with status monitoring equipment such as case temperature or processor speed monitor which appear on an LCD on the side.

A panel on the side, covers up and protects the inside of the computer when being used, which usually slides on and held with a screw. Most cases require a large amount of screws to put together. Recently there has been a move to "screwless" cases, where cases are held together with other methods than screws.

The Many Looks of Computer Cases

Traditional designs were beige in color and were rectangular (often referred to as "beige box"), but they have evolved in style in recent years, especially after the introduction of the iMac in 1998. Beige box designs are now typically found on budget machines.

The term "case modding" refers to the artistic styling of otherwise rather functional and plain computer encasings. There is an increasing demand for more functional and radical designs on computer cases and in the future computer cases may look very different from now. Companies such as Alienware are known for unusual cases.

Stickers are a common appearance on cases. These often include the computer manufacturer's logo and the computer's specifications (CPU, RAM, Hard drive, etc). Other stickers include the operating system (such as "Designed for Windows XP") and processor (such as the famous "Intel Inside" sticker).
--- Paul LoIacono is the president and owner of ATX Cases. You can see a wild array of computer case shapes, sizes and designs by visiting http://atxcases.com.