Input devices, processing and output devices
Input devices allow us to enter raw data [data: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information ] into a computer. The computer processes the data and then produces outputs [output: the term denoting either an exit or changes which exit a system and which activate/modify a process ] that we can understand using an output device. Input devices can be manual or automatic.
The processing is mainly handled by the Central Processing Unit (CPU).
The most common manual input devices are the keyboard and mouse. Other manual input devices include:
Each button on a concept keyboard relates to a particular item or function. Buttons can be labelled with text or a picture. Fast food restaurants often use concept keyboards because very little training is needed to operate them and they're efficient - a single button can order an entire meal.
Used as an alternative to a mouse. To operate it the user rotates the ball which moves the pointer on screen. They are particularly easy to use for those with limited movement in their hands and are often used in Computer Aided Design (CAD) for their increased precision over a mouse.
Joysticks used to be popular with gamers but have slowly been replaced by other types of game controller. In construction, joysticks are used to control machinery such as cranes.
A digital camera takes pictures and can usually record video too. The pictures it takes and the videos it records are stored in files. These files can be copied to a computer and later edited.
Microphones are used to input sound. In computing they can be used with voice recognition software [software: a general term used to describe an application or a program ] and a word processing application [application: applications serve a specific purpose, eg Microsoft Word is used for word processing ] to enter text. Webcams commonly have microphones built-in too.
A touch sensitive visual display unit (VDU) or screen has a grid of light beams or fine wires criss-crossing the screen that are used to detect touch. Many mobile phones use touch screens and do away with the keypad entirely. They're often used on cash machines and in shopping centres too. Touch screens are robust, easy to operate and easy to reprogram.
A video digitiser takes an image from a video camera or television and digitises it so it can be read by, and stored on, a computer. Video sequences captured using a video digitiser are often used in multimedia [multimedia: the use of several types of media outputs from a computer in order to give the user a richer and more interesting experience ] presentations [presentation: the practice of showing and explaining the content of a topic to an audience or learner ].
A scanner can be used to digitise images. They're similar to a photocopier but they make a digital [digital: data measured at discrete intervals, eg a digital watch typically moves from displaying one second to the next without displaying the values in-between ] copy instead of a physical copy. They can also be used with optical character recognition (OCR) software to scan in text that is then editable.
A graphics tablet consists of a flat pad (the tablet) on which the user draws with a special pen. As the user draws on the pad the image is created on the screen. Using a graphics tablet a designer can produce very accurate on-screen drawings as if they were drawing on paper.