Size and Shape of Computer chassis
chassis can come in many different sizes or "form factors". The most common form factor is ATX, although small form factor chassis are becoming popular for a variety of different uses.
chassis 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 chassis are taller and typically have more room while desktop chassis are more compact and are more popular in business environments.
Small form factor chassis are a variety of chassis that are coming more and more common. Companies like Shuttle computers and AOpen have been producing such chassis and Mini-ITX is the most common motherboard designed for these chassis. Apple Computer recently announced its Mac Mini computer, which is around the size of a CD-ROM drive.
Computer chassis Functions
chassis 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 chassis, its I/O ports being exposed on the side of the chassis. Usually the power supply unit is at the top of the chassis attathed with several screws. The typical chassis 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 chassis come with status monitoring equipment such as chassis 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 chassis require a large amount of screws to put together. Recently there has been a move to "screwless" chassis, where chassis are held together with other methods than screws.
The Many Looks of Computer chassis
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 "chassis 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 chassis and in the future computer chassis may look very different from now. Companies such as Alienware are known for unusual chassis.
Stickers are a common appearance on chassis. 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).