Computing Science
National 4 & National 5
Unit 1
Information Systems Design & Development
Topic 7a
An Introduction to Computer Structure & Architecture
N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Contents
Contents............................................................................................................................ 2
Introduction ...................................................................................................................... 3
What is a computer? ........................................................................................................ 3
Made in Britain ................................................................................................................. 4
Alan Turing ........................................................................................................................ 5
The Turing Test ................................................................................................................. 5
Types of computer ............................................................................................................ 8
Parts of a computer ........................................................................................................ 11
Hardware ........................................................................................................................ 12
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Introduction
You have probably already used several computers today without realising it.
If you have sent a text, been driven in a car, or checked your watch then you have used a
computer. The words you are reading now were typed on a computer.
Computers are all around us. Since they affect so many parts of our lives, it is important
to understand how they work.
What is a computer?
Have you ever wondered what the word “computer” means? If you look it up in a
dictionary, you will find something like:
“an electronic device which runs a program to process data at great speed”
We will come to the words program and data soon; however, the word “computer”
means “something that computes”.
So what does “compute” mean? Well, it means to calculate or work out.
The very first computers were actually people.
They did sums – all day, every day!
From around the 1700s until the 1950s, teams
of these “computers” used to carry out
complex calculations (and check each other’s
work).
The Computer Room at NASA (opposite)
This photograph shows human computers
working at NASA as late as 1949.
What would be the problem in doing calculations this way?
_______________________________________________________________________
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Made in Britain
Around 1940, the first electronic
computers began to appear.
There is debate about what was the very
first, but Britain led developments with
Colossus. This early computer was built
and used by British Intelligence to break
secret German codes during World War
II.
Colossus was huge (it took up an entire room) and had a tiny fraction of the power of a
modern computer or even a smartphone. Nevertheless, the work done using Colossus
and other machines like it is said to have shortened World War II by at least two years1 –
saving millions of lives.
A computer is a machine that carries out instructions given to it by a human. Without
instructions, computers wouldn’t be able to do anything.
If this is the case, then what makes them special? Well, computers…



work faster than humans 2 ;
are more accurate than humans;
can store huge amounts of information that they never “forget”.
It might seem that computers can do almost anything. However, here are some other
important things to remember:


Activity
Computers don’t have brains; they are not cleverer than humans.
Computers don’t have feelings or “common sense”. This means that there are
lots of everyday tasks that humans can perform that computers still cannot.
Write down three everyday tasks that humans perform but computers cannot (or are
not very good at).
1. _____________________________________________________________________
2. _____________________________________________________________________
3. _____________________________________________________________________
1
Hinsley, Francis Harry (1993), British intelligence in the Second World War: Cambridge University
Press, ISBN 978-0-521-44304-3
2 At the time of writing (2013), a modern personal computer could perform over 100 billion
calculations every second!
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Alan Turing
One of the people who worked on this and other early
computers was Alan Turing.
Turing was a genius whose ideas laid the foundations for
what would become the subject of Computing Science.
One of Turing’s main ideas was that a computer could
perform the task of any human, provided it was given the
correct instructions (program).
Because of this and many other feats, Turing has been
described as “The Father of Computing Science”. In 2012,
events took place around the world to celebrate what would have been his 100th
birthday.
The Turing Test
In 1950, Alan Turing posed a question that has occupied the minds of leading experts in
many fields since. He asked: “Can machines think?”
To help answer the question, he proposed a test which would, he said, determine if a
computer could think. This has become known as The Turing Test.
In the Turing Test, a person asks questions via a
keyboard to:


a computer (A) and
a human (B).
If the person asking the questions cannot tell the
human and the computer apart from the answers
given, Turing claimed that the computer has passed
the test and could be said to be intelligent.
The wider field of machine intelligence has become
known as Artificial Intelligence (AI).
Try the following chat programs online then answer the questions that follow overleaf:
• http://nlp-addiction.com/eliza/
• http://cleverbot.com/
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
What was it like talking to Eliza?
_______________________________________________________________________
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What was it like talking to Cleverbot?
_______________________________________________________________________
_______________________________________________________________________
How were Eliza and Cleverbot similar?
_______________________________________________________________________
_______________________________________________________________________
How were Eliza and Cleverbot different?
_______________________________________________________________________
_______________________________________________________________________
When did it seem like you were talking to a human?
_______________________________________________________________________
_______________________________________________________________________
When did it seem like you were not talking to a human?
_______________________________________________________________________
_______________________________________________________________________
Which chatbot did you like talking to more? ____________________________________
Why? __________________________________________________________________
_______________________________________________________________________
If you could not tell whether you were talking to a human or a machine, does it mean
that the machine is intelligent?
Yes/No ___________
Explain your answer ____________________________________
_______________________________________________________________________
_______________________________________________________________________
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Give examples of some machines that you think show some kind of “intelligence”.
Below each one, describe a way in which you think it is intelligent.
Machine: Satellite navigation unit (e.g. in-car satnav)
What makes it intelligent: Can work out the fastest route for a journey (which is not
always the shortest). Can even allow for how busy routes will be at certain times of the
day.
Machine:
What makes it intelligent:
Machine:
What makes it intelligent:
Look around at your classmates. Can you be sure that they are thinking just like you?
What if they’re actually very sophisticated robots with built-in chatbot programs…?! 3
How would you know? Discuss this with your (human) partner and write down your
ideas.
3
No one is seriously suggesting this is the case, but it maybe says something about how humans
react to each other. This is a common theme in science fiction.
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Types of computer
Computers come in many shapes and sizes. Computers that most people might
recognise include:
Activity
Desktop
A desktop PC (Personal Computer) is designed to
sit on top of – or under – a desk and is used by
one person at a time. It is powered by mains
electricity and made up of separate devices.
Laptop
Laptop computers combine all the separate devices
of a desktop PC into one unit. This can be carried
around and powered by mains electricity or battery.
Netbooks and ultrabooks are just smaller, lighter
types of laptop.
Tablet
This has a large, touch sensitive screen which is
used with your finger (or sometimes a special pen).
It is battery-powered and very portable. Tablets
have an on-screen “virtual” keyboard4.
The personal computers shown above appear in order of oldest to newest types.
What does this tell you about the kind of computers people want?
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
4
The word “virtual” is used a lot in Computing. It just means “not real” – it’s something that’s
been recreated on a computer. Can you think of any other virtual things you get on a computer?
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Other computers that may not be as well-known or recognised by most people include:
Mainframe
This is a large computer which can take
up an entire room. Many users can use
it at the same time, each with their
own keyboard, mouse and monitor.
Mainframes are very expensive and
need a team of people to run them.
They are owned by large organisations
that need to store and process huge
amounts of information.
Server
A server is a computer that provides
services for other computers on a
network e.g.



Games console
file server (stores users’ files)
web server (serves out web pages)
mail server (provides email services)
Games consoles are also computers. Most
have a disc drive for loading games and a
powerful processor to create realistic graphics.
Many games consoles can also connect to the
Internet, letting users buy games online or
compete with other gamers around the world.
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N4/ N5 Computing Science
Embedded
An Introduction to Computer Structure & Architecture
Many devices in your home have an embedded
computer – a small silicon chip that carries out
stored instructions. The modern home has over 100
of these “computers”, built into devices like a
toaster, stereo, washing machine, fridge, TV, etc.
A modern car may have another 100 or more embedded computers5.
Activity
Write down three devices in your own home that you think might contain an
embedded computer (besides those shown above).
1. _____________________________________________________________________
2. _____________________________________________________________________
3. _____________________________________________________________________
Smartphone
“Smart” mobile phones like Android and Apple iPhone
are really pocket computers that can also make phone
calls. Many smartphones use large touch screens.
This is a good example of convergence where
technologies that were previously separate are now
combined in one device. Another example is modern
TVs, some of which combine TV, browsing the Internet
and a DVD technologies.
Activity
Write down three technologies that are combined in a modern smartphone.
1. _____________________________________________________________________
2. _____________________________________________________________________
3. _____________________________________________________________________
5
Source: http://www.eetimes.com/discussion/significant-bits/4024611/Motoring-withmicroprocessors
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
Parts of a computer
A computer is a machine that:
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


takes in information
stores this information
processes this information
and gives this processed information back out.
PROCESS
INPUT
OUTPUT
STORAGE
Activity
Write down inputs and outputs for the following activities on different types of
computers. When you have finished, create an extra one of your own:
Activity
Input(s)
Output(s)
Playing a video game
Move game controller
Click buttons
Character moves
Menu selections made
Surfing the WWW
Making a phone call
Watching TV
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N4/ N5 Computing Science
An Introduction to Computer Structure & Architecture
There are two main parts to a computer: hardware and software (which we will look at
later).
Hardware
Hardware means computer equipment. A single piece of hardware
is called a device.
There are four main types of device in a computer:
Input device
used to put data into the computer
Central Processing Unit (CPU)
where the computer carries out the instructions
given by the programs. The faster the processor, the
faster your computer will work.
Output device
used for data coming out of the computer
Storage device
used to store programs and data. It is where you save
your work on to.
Put simply – if you can touch it, it’s hardware.
Activity
Decide if the following devices are input, output or storage devices then put each one
into the correct column (Note: Some devices can be in more than one column). The
first three have been done for you.
keyboard; hard disc drive; monitor; speaker; scanner; printer; mouse; DVD drive;
microphone; memory stick; game controller; smartphone touch screen; memory card
Input Device
Storage Device
Output Device
keyboard
hard disc drive
monitor
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Trinity High School
An Introduction to Computer Structure & Architecture
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