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Main » 2013 » August » 11 » INPUT AND OUTPUT DEVICES
9:04 PM INPUT AND OUTPUT DEVICES |
INPUT DEVICES
These accept input data/programmes for processing converting if necessary into a form which
the computer can understand and operate on. Input is a labour intensive process, typically
involving the keying in of data using a keyboard. In many cases, transcription the process of
inputting data by keyboard so that it can be converted into the electronic pulses on which the
computer circuitry operate is avoided by a process of data capture, where data is recorded in such
a way as to be directly convertible into a machine sensible form without any human intervention.
In many situations, data capture or transcription occurs far away from the main computer and
data has to be transmitted to where it is to be processed.
Examples of Input device are:
. The Keyboard
. The Visual Display Unit (VDU)
. Mouse
. Trackball
. Document Reading Devices
http://www.unaab.edu.ng
. Scanner
2.6 OUTPUT DEVICES
These accept output from the data processing device and convert it into a form suitable for use
by the computer's human operators. The commonest methods of computer output are printers and
screen display although it is also possible to output onto microfilm or fiche and onto
transparencies for overhead projection. Many home computers also produce sound output
through speakers.
Examples are:
Printers
The VDU - Visual Display Unit
Graphical User Interface (GUIs)
THE CHOICE OF OUTPUT MEDIUM
The choice of output medium depends on a number of factors
* Is a HARD copy of the output required? If so, what quality?
* The volume of information may affect the choice. It becomes more difficult using VDU when
information goes 'off screen' and can only be read a 'page' at a time.
* The speed at which output is required. A large volume of data requires a high-speed printer.
* The stability of the output medium to the application should be considered. A VDU is well
suited for interactive processing.
. The cost of acquiring the output device must be worth having them.
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