ICT Second Opportunity

1. Computer System

1.1 Hardware

Hardware is defined as a join of components of physical devices that intervene in a computer system.

It is also noun as the mechanical equipment necessary for conducting an activity, usually distinguished from the theory and design that make the activity possible.

http://dictionary.reference.com/browse/hardware

The components of a computer can be classified, according to the function they perform in: Input devices, Output devices, Processing and Storage.

1.1.1 Input Devices

They are the ones from which the information is introduced to the computer to be processed or transformed. Some examples are: keyboard, bar code reader, scanner, mouse, webcam, microphone, touch screen, etc.

Many input devices can be classified according to:

• Modality of input (e.g. mechanical motion, audio, visual, etc.)

• The input is discrete (e.g. key presses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is fast enough to be considered continuous)

• The number of degrees of freedom involved (e.g. two-dimensional traditional mice, or three-dimensional navigators designed for CAD applications)

Pointing devices, which are input devices used to specify a position in space, can further be classified according to:

• Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is done in the space where visual feedback or the pointer appears. Touchscreens and light pens involve direct input. Examples involving indirect input include the mouse and trackball.

• Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and repositioned)

http://en.wikipedia.org/wiki/Input_device

1.1.2 Output Devices

They are the ones that show the user the data previously transformed or processed. The most used are: the printer, which shows the information in written form, the monitor, which presents the information in a visual form, the speakers, which present the information in sound form.

Display device

A display device is an output device that visually conveys text, graphics, and video information. Information shown on a display device is called soft copy because the information exists electronically and is displayed for a temporary period of time. Display devices include CRT monitors, LCD monitors and displays, gas plasma

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