COMPUTER CASE

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

Contents

Size and shape

Layout

Major component locations

Internal access

Appearance

Brands

Intrusion detection

See also

External links

Size and shape

Cases can come in many different sizes, or 'form factors'. The size and shape of a computer case is usually determined by the form factor of motherboard that it is designed to accommodate, since this is the largest and most central component of most computers. Consequently, personal computer form factors typically specify only the ''internal'' dimensions and layout of the case. Form factors for rack-mounted and blade servers may include precise ''external'' dimensions as well, since these cases must themselves fit in specific enclosures.
For example, a case designed for an ATX motherboard and power supply may take on several external forms, such as a vertical ''tower'' (designed to sit on the floor) or a flat ''desktop'' or ''pizza box'' (designed to sit on the desk under the computer's monitor)). Full-size tower cases are typically larger in volume than desktop cases, with more room for drive bays and expansion slots. Desktop cases—and ''mini-tower'' cases designed for the reduced microATX form factor—are popular in business environments where space is at a premium.
As of 2007, the most popular form factor for desktop computers is ATX, although microATX and small form factors have become very popular for a variety of uses. Companies like Shuttle Inc. and AOpen have popularized small cases, for which FlexATX is the most common motherboard size. Apple Computer has also produced the Mac Mini computer, which is similar in size to a standard 5.25 inch CD-ROM drive.

Layout

Computer cases usually include sheet metal enclosures for a power supply unit and drive bays, as well as a rear panel that can accommodate peripheral connectors protruding from the motherboard and expansion slots. Most cases also a power button or switch, a reset button, and LEDs to indicate power status, hard drive usage, and network activity. Some cases include built-in I/O ports (such as USB and headphone ports on the front of the case). Such a case will also include wires needed to connect these ports to the motherboard.

Major component locations

★ The 'motherboard' is usually screwed to the bottom or the side of the case (depending on the form factor and orientation).

★ Form factors such as ATX provide a back panel with cut-out holes to expose ''I/O ports'' provided by integrated peripherals, as well as expansion slots which may optionally expose additional ports provided by expansion cards.

★ The ''power supply unit'' is often housed at the top rear of the case; it is usually attached with several screws to support its considerable weight.

★ Most cases include ''drive bays'' on the front of the case; a typical ATX case includes four 5.25" and three 3.5" bays. In modern computers, the former are used mainly for optical drives, while the latter are used for hard drives, floppy drives, and card readers.

★ Buttons and LEDs are typically located on the lower part of the front of the case; some cases include additional I/O ports, or temperature or processor speed monitors, in this area as well.

Internal access

Many modern tower cases have a single side panel which may be removed in order to access the internal components. Until recently, most computer cases required a large number of screws to hold components and panels in place: motherboard, PSU, drives, and expansion cards were all fastened with screws. As of 2006 there is a trend toward "screwless" cases, in which components are held together with snap-in plastic rails, thumbscrews, and other methods that do not require tools. This facilitates quick assembly and modification of computer hardware.

Appearance

Through the late 1990s, most computer cases had simple rectangular shapes, and were often painted beige. Beige box designs are still found on a large number of budget computers assembled from generic components. Many computer users still prefer the traditional rectangular shape of a tower case.

The 1998 introduction of the groundbreaking Apple iMac led to greater enthusiasm for imaginative case designs. Apple has continued to lead in the area of computer aesthetics, and has produced several innovative computers in small cases. Companies like Shuttle and AOpen have tapped the demand for small but customizable cases. The influence of these designs has led major OEM computer vendors, such as Dell and HP, to sell computers in more eye-catching cases, which may feature rounded edges, engraved logos, and translucent materials—all of which were pioneered by Apple. As of 2007, many OEM computer cases have black or dark gray color, with metallic silver-colored accents.

'Case modding' is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components. Since the early 2000s, some cases have included clear side panels or acrylic windows so that user can look inside while it is operating. Modded cases may also include internal lighting, custom paint, or liquid cooling systems. Some hobbyists build custom cases from raw materials like aluminum, steel, acrylic, or wood.
Stickers are common on computer cases. These may advertise the manufacturer's logo, a list of the computer's specifications, the intended operating system (for example, "Designed for Windows XP"), or the microprocessor used (such as Intel Inside).

Brands

Prominent after-market case manufacturers include Ahanix, Antec, AOpen, Chieftec, Cooler Master, Ever Case, HEC Compucase, IXIUM, Lian Li, NZXT, OrigenAE, Raidmax, Shuttle Inc., SilverStone Technology, Thermaltake and Zalman.

Intrusion detection

Some computer cases include a biased switch (push-button) which connects to the motherboard. When the case is opened, the switch position changes, and the system records this change. The system firmware or BIOS may be configured to report this event the next time it is powered-on.
This serves as a physical intrusion detection system, and may help computer owners to detect tampering with their computer. However, most such systems are quite simple in construction; a knowledgeable intruder can open the case or modify its contents without triggering the switch, for example by reaching inside the case through a drive bay.

See also

★ Small form factor

★ Motherboard

★ Case modding

★ List of computer hardware manufacturers

External links

★ Chassis Form Factors