case: computer cases are usually made from such materials as steel, aluminum, or
plastic and encloses the main components of a
Other names for the computer case is chassis, cabinet, tower, box, enclosure or
housing. Cases have different form factors and different sizes. The size
and shape of a
computer case is
determined mostly by the
since it is the central and largest component. The form factors of
usually specify the inside dimensions and the layout of the case. Other
considerations for form factors are rack-mounted and blade servers which may
involve precise external dimensions as the cases must fit themselves into
Examples of different form factors: an ATX
supply may take on several different external forms, such as a vertical tower
(which sits on the floor) or a flat
desktop or pizza
box (which sits on the desk under the
monitor)). Full-size tower cases are usually larger in size than
with more room for
and expansion slots.
Desktop cases and mini-tower cases designed for the reduced microATX form
factor are popular in business environments as space is usually at a premium in
Although microATX and small form factors have become very popular for a
variety of uses, as of 2007, the most popular form factor for desktop
computers is ATX.
Apple Computer has created the Mac Mini
is similar in size to a standard 5.25 inch
drive. Other companies like Shuttle Inc. and AOpen have popularized small cases, for
which FlexATX is the most common
- Depending on the form factor and orientation, the
motherboard is usually found screwed to the bottom or to the side of the case.
- 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.
power supply unit is often found at the top rear of the case; because of
its considerable weight, it is
usually attached with several screws.
- Most cases include
on the front of the case; a typical ATX case includes four 5.25" and three
3.5" bays. In modern
former are used mainly for optical drives, while the latter are used for
floppy drives, and card readers.
- Buttons and LEDs are usually found on the lower part of the front of
the case; also in this area, some cases include additional I/O ports, or
temperature or processor speed monitors.