Last updated: 23/01/2013
Dedicated Computer Systems
Syllabus
Notes
General purpose computer
Can a car become a plane or a plane become a car? In the world of machines, each machine is usually
built for a particular function, such as getting you somewhere, washing your clothes or playing music.
Computers however are different because when they are built, the manufacturer doesn’t know what it
will be used for as everyone will use it for different reasons.
Such a computer is called a general purpose computer, which is a computer which is controlled by a
program and the program can be easily changed. It is not designed to be very good at a particular task. If
you want the computer to do something different, you just change the program that is running. For
example, if you want the computer to become a typewriter, you run a word processing program, if you
want the computer to become a jukebox, you run an mp3 player program.
Special purpose computer
A special purpose computer (or dedicated computer) on the other hand is a computer which uses a
program which is difficult to change. Such a computer would be designed to be very good at some
specific task and usually does nothing else. Examples of this are DVD players, satellite navigation
systems and automatic teller machines (ATMs). Programs for such a computer would probably only run
on this type of computer.
An “embedded computer” is a special purpose computer which is part of another machine, such as a
computer inside a car, which might be used to automatically park the car, or air conditioner, which
might be used to regulate the temperature. It is not used directly by the user; instead the computer is
there to be used by the machine which is itself used directly by the user.
Input and output for a special purpose computer need not be general purpose like a mouse or monitor.
Input and output for a special purpose computer only needs to be used for one task and could be as
simple as a button, such as in a stopwatch, or a keypad, such as in an automatic teller machine or a light
bulb, such as in a burglar alarm, or an LCD numeric display, such as in a calculator.
By Mr. Tanti www.teachertanti.com
Page 1 of 2
Last updated: 23/01/2013
Further reading
A Complete Computing Course
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Chapter 2.1
Chapter 2.2.6
Past papers
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2006
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2008
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2009
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2011
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IIA
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4f
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5b
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6d
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5
IIA
IIA
I
By Mr. Tanti www.teachertanti.com
Page 2 of 2