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A peripheral is any computer device that
is not part of the essential computer, but is situated relatively close by. A near synonym
is any input/output (I/O) device such as PS2, serial, parallel,
SCSI, USB or firewire. Standard computer peripheral includes a
mouse or other pointing device
and a keyboard. Options generally
include game devices such as joysticks, gamepads and wheels, printers,
scanners, cameras and
memory card readers among others.
External CD-ROM's, backup devices and external modems are also
considered peripherals. They can be physically attached or cordless. The mouse is a small device that a computer
user pushes across a desk surface in order to point to a place on a display screen and to
select one or more actions to take from that position. The mouse first became a
widely-used computer tool when Apple Computer made it a standard part of the
Macintosh. Today, the mouse is coming with all sorts of shapes, sizes and additional
functions. Touchpads and trackballs are other types of
pointing devices.
The keyboard
is the primary text input device. The keyboard also contains certain standard function
keys, such as the Escape key, tab and cursor movement keys, shift and control keys, and
sometimes other manufacturer-customized keys. The computer keyboard uses the same key
arrangement as the mechanical and electronic typewriter keyboards that preceded the
computer. The standard arrangement of alphabetic keys is known as the Qwerty (pronounced
KWEHR-tee) keyboard, its name deriving from the arrangement of the five keys at the upper
left of the three rows of alphabetic keys. This arrangement, invented for one of the
earliest mechanical typewriters, dates back to the 1870s. The ergonomic keyboard is a
popular today. Ergonomic keyboards have been proven to be orthopedic is relieving stress. |
