Cambridge IGCSETM
Computer Science
For over 60 years Marshall Cavendish Education has been
empowering educators and students in over 80 countries with
high-quality, research-based, Pre-K-12 educational solutions.
We nurture world-ready global citizens by equipping students
with crucial 21st century skills through our resources for schools
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catering to national and international curricula.
The Marshall Cavendish Education Cambridge IGCSETM Computer Science series
is designed for students studying for the Cambridge IGCSE and IGCSE (9–1)
Computer Science syllabuses (0478/0984). The series focuses on developing
important computer science skills relevant to real-world applications.
Cambridge
IGCSE
TM
Computer Science
WB The Workbook follows the same flow and structure as the Student’s Book and provides supplementary
exercises for students to reinforce concepts learnt during lessons and familiarise themselves with the
syllabus requirements. A revision checklist at the end helps students assess their level of understanding
of concepts.
✓ Provides learner support for the Cambridge
IGCSE and IGCSE (9–1) Computer Science syllabuses
(0478/0984) for examination from 2023.
✓ Has passed Cambridge International’s rigorous
Series architecture
• Student’s Book
• Workbook
• Teacher’s Guide
• e-book
WORKBOOK
This resource is endorsed by
Cambridge Assessment International Education
quality-assurance process
✓ Developed by subject experts
✓ For Cambridge schools worldwide
Kay Summers
WORKBOOK
ISBN 978-981-4941-60-0
9 789814 941600
C01(S)IGCSECS_WB_Cover.indd All Pages
27/5/21 10:13 AM
How to Use This Book
For further learner support, alongside the Student’s Book,
the Workbook offers a range of exercises to reinforce and
consolidate key terms and concepts learnt from each chapter.
This Workbook is part of the Marshall Cavendish Education
suite of resources that will support you with your study of
Cambridge IGCSETM and IGCSE (9–1) Computer Science
syllabuses (0478/0984).
Formative Exercises
These exercises are meant to evaluate how well you
are learning each section in a chapter.
They are intended to help build your subject literacy
and boost your confidence in understanding and
answering questions.
Revision checklist
This exercise is included at the end
of each chapter to help you identify
knowledge gaps. It is designed for
you to pause and reflect on your
learning experience by evaluating your
understanding of the concepts taught.
iii
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Contents
HOW TO USE THIS BOOK
1
Computer systems
Exercise 1.1 Number systems
Exercise 1.2 Text, sound and images
Exercise 1.3 Data storage and compression
2
Data transmission
Exercise 2.1 Types and methods of data transmission
Exercise 2.2 Methods of error detection
Exercise 2.3 Encryption
3
Hardware
Exercise 3.1 Computer architecture
Exercise 3.2 Input and output devices
Exercise 3.3 Data storage
Exercise 3.4 Network hardware
4
Software
Exercise 4.1 Types of software and interrupts
Exercise 4.2 Types of programming language, translators and
integrated development environments (IDEs)
5
The internet and cyber security
Exercise 5.1 The internet and the world wide web
Exercise 5.2 Digital currency
Exercise 5.3 Cyber security
6
Automated and emerging technologies
Exercise 6.1 Automated systems
Exercise 6.2 Robotics
Exercise 6.3 Artificial intelligence
7
Algorithm design and problem solving
Exercise 7.1 Algorithm design and problem solving
8
Programming
Exercise 8.1 Programming concepts
Exercise 8.2 Arrays
Exercise 8.3 File handling
9
Databases
Exercise 9.1 Databases
10 Logic gates and circuits
Exercise 10.1 Boolean logic
iii
1
1
12
15
17
17
23
25
27
27
32
34
38
42
42
46
50
50
53
53
58
58
61
63
66
66
91
91
107
111
115
115
123
123
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1
CHAPTER
Computer systems
At the end of this chapter, you will be able to:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Understand how and why computers use binary to represent all forms of data
Understand the denary, binary and hexadecimal number systems
Convert between positive denary and positive binary, positive denary and hexadecimal, and hexadecimal and
positive binary
Understand how and why hexadecimal is used as a beneficial method of data representation
Add two positive 8-bit binary integers
Understand the concept of overflow and why it occurs in binary addition
Perform a logical binary shift on a positive 8-bit binary integer and understand the effect this has on the positive
binary integer
Use two’s complement to represent positive and negative 8-bit binary integers
Understand how and why a computer represents text and the use of character sets, including ASCII and Unicode
Understand how and why a computer represents sound, including the effects of the sample rate and sample resolution
Understand how and why a computer represents an image, including the effects of the resolution and colour depth
Understand how data storage is measured
Calculate the file size of an image file and a sound file, using information given
Understand the purpose of and need for data compression
Understand how files are compressed using lossy and lossless compression methods
1.1 Number systems
A number system is a method for representing values based on a particular set of units. There are three number systems that you
will use here: denary, binary and hexadecimal.
Exercise 1
1
Is denary a base-2, base-10 or base-16 number system? Circle the correct answer.
Base-2
2
Denary, binary and hexadecimal
Base-10
Base-16
Is binary a base-2, base-10 or base-16 number system? Circle the correct answer.
Base-2
Base-10
Base-16
Computer systems
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Chapter 1
3
Is hexadecimal a base-2, base-10 or base-16 number system? Circle the correct answer.
Base-2
Base-10
Exercise 2
Base-16
Converting denary values
Denary values can be converted to binary values and vice versa.
1
Convert the denary value 7 to a 4-bit binary value.
Denary
4-bit binary
7
Working space
2
Convert the denary value 10 to a 4-bit binary value.
Denary
4-bit binary
10
Working space
3
Convert the 4-bit binary value 0011 to denary.
4-bit binary
Denary
0011
Working space
4
Convert the 4-bit binary value 1001 to denary.
4-bit binary
Denary
1001
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Chapter 1
Working space
5
Convert the denary value 24 to an 8-bit binary value.
Denary
8-bit binary
24
Working space
6
Convert the denary value 101 to an 8-bit binary value.
Denary
8-bit binary
101
Working space
7
Convert the denary value 200 to an 8-bit binary value.
Denary
8-bit binary
200
Working space
8
Convert the 8-bit binary value 00011011 to denary.
8-bit binary
Denary
00011011
Working space
Computer systems
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Chapter 1
9
Convert the 8-bit binary value 10011111 to denary.
8-bit binary
Denary
10011111
Working space
10 Convert the denary value 555 to a 12-bit binary value.
Denary
12-bit binary
555
Working space
11 Convert the denary value 2001 to a 12-bit binary value
Denary
12-bit binary
2001
Working space
12 Convert the 12-bit binary value 100110011001 to denary.
12-bit binary
Denary
100110011001
Working space
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Chapter 1
13 Convert the denary value 1056 to a 16-bit binary value.
Denary
16-bit binary
1056
Working space
14 Convert the denary value 5000 to a 16-bit binary value.
Denary
16-bit binary
5000
Working space
15 Convert the 16-bit binary value 0011010111001100 to denary.
16-bit binary
Denary
0001010111001100
Working space
Exercise 3
Converting hexadecimal values
Denary and binary values can also be converted to hexadecimal, and vice versa.
1
Convert the 4-bit binary value 0011 to hexadecimal.
4-bit binary
Hexadecimal
0011
Working space
Computer systems
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Chapter 1
2
Convert the 4-bit binary value 1001 to hexadecimal.
4-bit binary
Hexadecimal
1001
Working space
3
Convert the 4-bit binary value 1110 to hexadecimal.
4-bit binary
Hexadecimal
1110
Working space
4
Convert the hexadecimal value 4 to 4-bit binary.
Hexadecimal
4-bit binary
4
Working space
5
Convert the hexadecimal value A to 4-bit binary.
Hexadecimal
4-bit binary
A
Working space
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Chapter 1
6
Convert the hexadecimal value F to 4-bit binary.
Hexadecimal
4-bit binary
F
Working space
7
Convert the 8-bit binary value 00001000 to hexadecimal.
8-bit binary
Hexadecimal
00001000
Working space
8
Convert the 8-bit binary value 10110001 to hexadecimal.
8-bit binary
Hexadecimal
10110001
Working space
9
Convert the 8-bit binary value 11000000 to hexadecimal.
8-bit binary
Hexadecimal
11000000
Working space
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Chapter 1
10 Convert the hexadecimal value 4B to 8-bit binary.
Hexadecimal
8-bit binary
4B
Working space
11 Convert the hexadecimal value CD to 8-bit binary.
Hexadecimal
8-bit binary
CD
Working space
12 Convert the hexadecimal value 3B0 to 12-bit binary.
Hexadecimal
12-bit binary
3B0
Working space
13 Convert the denary value 103 to hexadecimal.
Denary
Hexadecimal
103
Working space
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Chapter 1
14 Convert the hexadecimal value A3 to denary.
Hexadecimal
Denary
A3
Working space
15 Convert the hexadecimal value 2E to denary.
Hexadecimal
Denary
2E
Working space
16 Convert the 12-bit binary value 110100001111 to hexadecimal.
12-bit binary
Hexadecimal
110100001111
Working space
17 Convert the hexadecimal value 04C to 12-bit binary.
Hexadecimal
12-bit binary
04C
Working space
Computer systems
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Chapter 1
Exercise 4
Adding binary values
Binary values can be added together. Make sure that you show your working when adding the binary values.
1
2
Add the 4-bit binary values 0001 and 0110.
0 1 0 1
0 0 0 1
+ 0 1 1 0 3
Add the 4-bit binary values 0101 and 0010.
+ 0 0 1 0 4
Add the 8-bit binary values 00101000 and 01100011.
0 0 1 0 1 0 0 0
+ 0 1 1 0 0 0 1 1
Add the 8-bit binary values 10101010 and 01110111.
1 0 1 0 1 0 1 0
+ 0 1 1 1 0 1 1 1
5
Name the error caused by this binary addition.
6
Why does this type of error happen?
Exercise 5
Logical shifts
Logical shifts can be performed on the binary contents of a register.
1
Perform a logical binary shift one place to the left on this binary value.
0
1
0
0
1
1
1
1
What effect did the logical shift have on the binary value?
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Chapter 1
2
Perform a logical binary shift two places to the right on this binary value.
0
0
1
1
0
1
0
0
What effect did the logical shift have on the binary value?
Exercise 6
Two’s complement
Two’s complement is another method of representing binary values. It is often used to represent negative binary values.
1
Convert the denary number 47 to two’s complement 8-bit binary.
Denary
Two’s complement 8-bit binary
47
Working space
2
Convert the denary number -75 to two’s complement 8-bit binary.
Denary
Two’s complement 8-bit binary
-75
Working space
Computer systems
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Chapter 1
3
Convert the two’s complement 8-bit binary value 01010110 to denary.
Two’s complement 8-bit binary
Denary
01010110
Working space
4
Convert the two’s complement 8-bit binary value 10001011 to denary.
Two’s complement 8-bit binary
Denary
10001011
Working space
5
What is the largest number that can be stored in 8 bits using two’s complement?
6
What is the smallest number that can be stored in 8 bits using two’s complement?
1.2 Text, sound and images
In computing, text, sound and images are all converted to binary and then processed by the computer. Various methods are
used to obtain these binary values.
Exercise 1
Character sets
When converting text to binary, a character set is used.
1
What is a character set?
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Chapter 1
2
Tick (✔) to show whether each statement is true or false.
True
(✔)
Statement
False
(✔)
Both Unicode and ASCII are examples of a character set
Unicode requires more bits per character
ASCII can represent a greater range of symbols and emojis
Unicode can represent a greater range of different languages
Exercise 2
Sound waves
When converting sound to binary, sound waves are sampled.
1
What is the difference between the sample rate and the sample resolution?
2
How can you increase the accuracy of a sound file to make it sound more like the original?
3
A 10 second sound clip has a sample rate of 1000 Hz and a sample resolution of 8 bits.
Calculate the file size of the sound clip in kibibytes (KiB). Remember to show all your working.
Answer:
KiB
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Chapter 1
Exercise 3
Converting images to binary
When converting an image to binary, the resolution and colour depth are set.
1
Draw a line from each term to its correct definition.
Colour depth
The number of pixels in an image
Resolution
The number of bits used to represent
each colour in an image
Pixels
The small squares of colour that make
up an image
2
What will be the effect on an image if the colour depth is reduced?
3
A student has five images. Each image has a resolution of 1000 pixels wide by 800 pixels high. Each image has a colour
depth of 16 bits.
Calculate the file size needed to store the images in mebibytes (MiB). Remember to show all your working.
Answer:
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MiB
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Chapter 1
1.3 Data storage and compression
Several data storage units can be used to identify the size of a file.
Exercise 1
1
Data storage units
Number the data storage units from 1 (smallest) to 9 (largest).
The first one has been done for you.
Data storage unit
Number
Byte
Kibibyte (KiB)
Gibibyte (GiB)
Nibble
Exbibyte (EiB)
Mebibyte (MiB)
Tebibyte (TiB)
Bit
1
Pebibyte (PiB)
Exercise 2
File compression
Sometimes, files are compressed before they are stored. There are two methods of compression: lossy and lossless.
1
Tick (✔) to show whether each statement is true or false.
Statement
True
(✔)
False
(✔)
Compression reduces the size of the file
A compressed file will be transmitted slower
A compressed file uses less bandwidth when transmitted
A compressed file will take up less storage space
2
A student has several large images to send to a friend. They use lossy compression to reduce the size of the images before
sending them.
List two ways that lossy compression will reduce the size of the images.
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Chapter 1
3
The paragraph below explains how lossless compression can be used to reduce the size of a text file.
Fill in the missing words.
the size of the file. The algorithm looks for
A compression algorithm is used to
patterns in the text file and
them. Each index
along with the position where it occurs in the text.
is stored in a
Revision checklist
Need to revisit
Satisfactory
Confident
I understand how and why computers use binary to represent all
forms of data
I understand the denary, binary and hexadecimal number systems
I can convert between positive denary and positive binary, positive
denary and hexadecimal, and hexadecimal and positive binary
I understand how and why hexadecimal is used as a beneficial
method of data representation
I can add two positive 8-bit binary integers
I understand the concept of overflow and why it occurs in binary
addition
I can perform a logical binary shift on a positive 8-bit binary integer
and understand the effect this has on the positive binary integer
I can use two’s complement to represent positive and negative 8-bit
binary integers
I understand how and why a computer represents text and the use of
character sets, including ASCII and Unicode
I understand how and why a computer represents sound, including
the effects of the sample rate and sample resolution
I understand how and why a computer represents an image,
including the effects of the resolution and colour depth
I understand how data storage is measured
I can calculate the file size of an image file and a sound file, using
information given
I understand the purpose of and need for data compression
I understand how files are compressed using lossy and lossless
compression methods
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2
CHAPTER
Data transmission
At the end of this chapter, you will be able to:
•
•
•
•
•
•
•
•
•
•
•
•
•
Understand that data is broken down into packets to be transmitted
Describe the structure of a packet
Describe the process of packet switching
Describe how data is transmitted from one device to another using different methods of data transmission
Explain the suitability of each method of data transmission, for a given scenario
Understand the universal serial bus (USB) interface and explain how it is used to transmit data
Understand methods of error detection
Understand the need to check for errors after data transmission and how these errors can occur
Describe the processes involved in each of the following error detection methods for detecting errors in data after
transmission: parity check (odd and even), checksum and echo check
Describe how a check digit is used to detect errors in data entry and identify examples of when a check digit is used,
including ISBN numbers and bar codes
Describe how an automatic repeat request (ARQ) can be used to establish that data is received without error
Understand the need for and purpose of encryption when transmitting data
Understand how data is encrypted using symmetric and asymmetric encryption
2.1 Types and methods of data transmission
Exercise 1
Data packets
A document is too large a section of data to be transmitted from one device to another. There is no infrastructure capacity
to transmit such a large amount of data at once. Therefore, it needs to be broken down into packets, which are much smaller
units of data.
1
Name the three different sections in the structure of a data packet.
2
In which section of the data packet would you normally find the destination address?
Data transmission
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Chapter 2
3
What kind of address is the destination address normally?
4
In which section of the data packet would you find the main content of the data being sent?
5
In which section of the data packet would you normally find the packet number?
6
What kind of data might you find in the trailer of a data packet?
7
In packet switching, does each packet take the same route or can they take different routes? Circle the answer.
Same route Different routes
8
In packet switching, the data packets will always arrive in order.
Tick (✔) to show whether this statement is true or false.
Tick (✔)
True
False
9
What is the name of the network device that chooses the route a data packet will take?
10 In packet switching, when are the data packets reordered after transmission?
18
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Chapter 2
11 Draw a diagram to represent how data is transmitted across a network using packet switching. Your diagram should include
a minimum of two devices and four routers.
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Chapter 2
Exercise 2
Data transmission
Data is transmitted from one device to another using the serial or parallel method.
1
Tick (✔) to show how many wires are used in parallel data transmission.
Number of wires
Tick (✔)
Single wire
Multiple wires
2
Tick (✔) to show which method transmits data one bit at a time.
Data transmission method
Tick (✔)
Serial
Parallel
3
Describe the benefit of using parallel data transmission, instead of serial data transmission.
4 List two benefits of using serial data transmission, instead of parallel data transmission.
Exercise 3
Transmission methods
Data is also transmitted from one device to another using the simplex, half-duplex or full-duplex method.
1
Does simplex data transmission happen in one direction only or in both directions? Circle the answer.
One direction only Both directions
2 Can you think of two applications where simple data transmission would be suitable?
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Chapter 2
3
Draw a diagram to show how data is transmitted using half-duplex data transmission.
4 Can you describe how data is sent using full-duplex data transmission?
5
A website designer has a web server beside their desk. They need to be able to send data to and receive data from the web
server at the same time, and may also need to make quick changes to the data on the web server, so data transmission to
the web server is time critical.
Which data transmission methods should be used to send data from the website designer’s computer to the web server? Why?
6
An office manager creates a back-up of the data stored on her computer at the end of each day. The file server that stores
the back-up is located in a building 1 km from her office. It is very important the data is stored without error on the file
server. She only needs to send data to the back-up, and does not receive data from the file server.
Which data transmission methods should be used to send data from the office manager’s computer to the file server? Why?
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Chapter 2
Exercise 4
USB interface
An interface called USB can be used to connect one device to another.
1
Tick (✔) to show which type of data transmission is used in a USB connection.
Data transmission method
Tick (✔)
Serial
Parallel
2
List three benefits of using a USB interface to connect a mobile phone to a computer.
3
What are two drawbacks of connecting a server to a computer using a USB interface?
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Chapter 2
2.2 Methods of error detection
When data is transmitted from one device to another, there is a chance that errors can occur in the data. This could be because
packets of data go missing, or because of interference during transmission. Therefore, several error detection methods can be
used to find any errors.
Exercise 1
1
Error dectection
Which error detection method adds an 8th bit to 7 bits of data, to make each byte meet an odd or even check?
Circle the answer.
Parity check Checksum Echo check
2
In which error detection method does the receiver send data back to the sender, to compare the two versions of the data?
Circle the answer.
Parity check Checksum Echo check
3
Which error detection method uses an algorithm to calculate a value from the data? This value is transmitted with the data
to the receiver. Circle the answer.
Parity check Checksum Echo check
4
The following four bytes of data have been transmitted from one computer to another. Each byte was transmitted using an
even parity check. All the bytes have arrived correctly. Write the parity bit that was added to each byte for it to be correct for
an even parity check.
Parity bit
5
Byte
1
0
1
1
0
1
1
0
1
1
1
0
0
0
1
0
1
0
1
1
0
0
0
0
0
1
1
1
Can you think of a reason why an error that has occurred in the transmission of data from one device to another is not
detected by a parity check?
Errors can also occur when data is entered into a device. The data entry could be manual (being typed into a device),
or automatic (such as scanning a barcode). Therefore, there is also an error detection method for data entry, which is
called a check digit.
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Chapter 2
Exercise 2
1
Check digit
How is a check digit used to detect errors in data entry?
Exercise 3
Automatic repeat request
Sometimes errors are found in data after transmission. So, systems need a way to request that the data is resent. One method for
this is an automatic repeat request (ARQ).
1
During an ARQ process, data is transferred from the sending device to the receiving device. The sending device then
starts a timer. The receiving device checks the data for errors, using one of the error detection methods you have
studied. What happens next in the ARQ process?
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Chapter 2
2.3 Encryption
Data is very valuable and we should always make sure that it is stored and transmitted in a secure way. Encryption is one way
that data can be kept secure.
Exercise 1
Encryption
1
What is the name given to the data before encryption?
2
Name the type of transformation that is used to encrypt the data.
3
What is the name given to the data after encryption?
4
Tick (✔) to show whether the same key or different keys are used to encrypt and decrypt data in symmetric encryption.
Keys used
Tick (✔)
Same key
Different keys
The paragraph below explains how asymmetric encryption is used to encrypt data.
Fill in the missing words.
The
a
The
5
text is encrypted into
text using
key. The encrypted data is transmitted to the receiving device.
text is decrypted using a
key.
Which encryption method is more secure? Why?
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Chapter 2
Revision checklist
Need to revisit
Satisfactory
Confident
I understand that data is broken down into packets to be transmitted
I can describe the structure of a packet
I can describe the process of packet switching
I can describe how data is transmitted from one device to another
using different methods of data transmission
I can explain the suitability of each method of data transmission, for a
given scenario
I understand the universal serial bus (USB) interface and explain how
it is used to transmit data
I understand methods of error detection
I understand the need to check for errors after data transmission and
how these errors can occur
I can describe the processes involved in each of the following error
detection methods for detecting errors in data after transmission:
parity check (odd and even), checksum and echo check
I can describe how a check digit is used to detect errors in data entry
and identify examples of when a check digit is used, including ISBN
numbers and bar codes
I can describe how an automatic repeat request (ARQ) can be used to
establish that data is received without error
I understand the need for and purpose of encryption when
transmitting data
I understand how data is encrypted using symmetric and asymmetric
encryption
26
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3
CHAPTER
Hardware
At the end of this chapter, you will be able to:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Understand the role of the central processing unit (CPU) in a computer
Understand what is meant by a microprocessor
Understand the purpose of the components in a CPU, in a computer that has a von Neumann architecture
Describe the process of the fetch-decode-execute cycle including the role of each component in the process
Understand what is meant by a core, cache and clock in a CPU and explain how they can affect the performance of a CPU
Understand the purpose and use of an instruction set for a CPU
Describe the purpose and characteristics of an embedded system and identify devices in which they are commonly used
Identify a range of different input and output devices
Understand what is meant by an input device and why it is required
Understand what is meant by an output device and why it is required
Understand what is meant by a sensor and the purposes of sensors
Identify the type of data captured by each sensor and understand when each sensor would be used, including
selecting the most suitable sensor for a given context
Understand what is meant by primary storage
Understand what is meant by secondary storage
Describe the operation of magnetic, optical and solid-state (flash memory) storage and give examples of each
Describe what is meant by virtual memory, how it is created and used, and why it is necessary
Understand what is meant by cloud storage
Explain the advantages and disadvantages of storing data on the cloud in comparison to storing it locally
Understand that a computer needs a network interface card (NIC) to access a network
Understand what is meant by and the purpose of a Media Access Control (MAC) address, including its structure
Understand what is meant by and the purpose of an Internet Protocol (IP) address
Understand that there are different types of IP address
Describe the role of a router in a network
3.1 Computer architecture
A computer has many components that are needed for it to operate, but one of the most important is the CPU.
This component allows the computer to process all the data that is input into it, to create an output for the user.
Some systems have a smaller version of a CPU, because they don’t need to be as powerful. This smaller version of a CPU is
called a microprocessor. It is a type of integrated circuit that is built into a single chip.
A system that uses a microprocessor is normally called an embedded system. This is a particular type of system designed to
perform a dedicated single function or a very small set of functions. This is different to a general purpose computer that will
perform many different functions.
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Chapter 3
Exercise 1
Embedded systems
1
What is the main purpose of the CPU?
2
What is a microprocessor?
3
A washing machine is an example of an embedded system. List four more embedded systems.
4
A personal computer (PC) is one example of a general purpose computer. List two other examples.
Exercise 2
Fetch-decode-execute cycle
A process called the fetch-decode-execute cycle is performed by the CPU. This cycle fetches an instruction into the CPU, decodes
it, and then executes it. The CPU uses several different components to do this.
1
Where are data and instructions stored immediately before they are fetched into the CPU?
2
What is the purpose of a register?
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Chapter 3
3
Tick (✔) to show which of the following components are examples of a register.
Component
Tick (✔)
Program counter
Address bus
Memory address register
Data bus
Memory data register
Control bus
Arithmetic logic unit
Control unit
Current instruction register
Accumulator
4
Which register stores the address of the next instruction to be fetched into the CPU?
5
What is the purpose of the memory address register (MAR)?
6
When an instruction is fetched into the CPU, which component is it sent to first?
7
What is the purpose of the control unit?
8
The arithmetic logic unit (ALU) is used to execute an instruction. It has a built-in register. What is the name and purpose of
this register?
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Chapter 3
9
Data and signals are transmitted between the different components of the CPU using buses. Can you name the three buses
used for this?
10 Can you describe what happens at the fetch stage of the fetch-decode-execute cycle?
11 Can you describe what happens at the decode stage of the fetch-decode-execute cycle?
12 What is an instruction set?
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Chapter 3
Exercise 3
Components within the CPU
Certain factors can affect the performance of the CPU, including the number of cores, the size of the cache, and the speed
of the clock.
1
2
Draw a line from each component to its correct definition.
Component
Definition
Clock
The component within the CPU responsible for
performing a single fetch-decode-execute cycle
Core
The component that regulates the timing and
speed of a computer
Cache
The component that stores frequently used
data and instructions
A student has a computer with the following specifications:
●
2 GHz processor
●
Dual core processor
●
32 kB cache
Describe two ways the performance of the computer can be improved. Why would this improve the performance?
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Chapter 3
3.2 Input and output devices
An input device allows data to be entered into a system to be processed. An output device allows the user to obtain the output
of the processing of the data. This often involves being able to see or hear the results.
Exercise 1
1
Types of input/output device
Tick (✔) to show whether each device is an example of an input device or an output device.
Device
Input (✔)
Output (✔)
Keyboard
Speaker
3D printer
Barcode scanner
Mouse
Monitor
Actuator
Sensor
2
Which input device would be most suitable to enter a password into a computer?
3
Which input device would be most suitable to convert a hard copy of a document into a digital copy?
4
Which output device would be most suitable to allow shoppers to listen to an announcement in a supermarket?
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Chapter 3
5 Complete the crossword by identifying each of the sensors.
1.
2.
1.
3.
3.
4.
5.
4.
5.
6.
6.
7.
Clues
Across
Down
1. Captures static forces such as the continual force of gravity
and dynamic forces such as those created by vibrations.
1. Can be used to measure whether a substance, such as
fuel in a car, falls below a certain point.
2. Can be used in agriculture and farming to make sure that
the produce has the correct level of watering for growing.
2. Measures the presence of a magnetic force that can be
emitted by an object.
3. Can be used in people’s homes to measure the level of
carbon dioxide.
3. Measures how hot or cold a substance is.
4. Measures the level of sound in a certain environment.
4. Measures the force that is directly applied to the sensor or
a device by a solid, liquid or gas.
5. Measures the level of moisture in the atmosphere.
5. Measures the ambient illumination in a certain environment.
6. Can measure how much liquid is running through a pipe
in a factory.
6. Can be used in a security system to capture a type of
radiation emitted by an intruder.
7. Can measure whether soil is acidic or alkaline.
7. Measures how close an object is to the sensor.
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Chapter 3
Sensors are used to capture data from their immediate environment. This data can then be processed by a computer system
to allow monitoring and control systems to operate.
6
One benefit of sensors is that they can operate 24 hours a day, 7 days a week.
List three other ways sensors can be useful.
1
2
3
3.3 Data storage
Exercise 1
Types of storage
Computers use different types of storage, including primary and secondary storage. Primary storage is directly accessed by the
CPU and secondary storage is not directly accessed by the CPU.
1
Tick (✔) to show whether each example is primary storage or secondary storage.
Storage example
Primary
storage (✔)
Secondary
storage (✔)
Read only memory (ROM)
Hard disk drive (HDD)
Random access memory (RAM)
Solid state drive (SSD)
2
Which storage examples are directly connected to the CPU?
3
Can you name three storage examples that are described as non-volatile because they do not lose the data they store when
power is turned off?
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Chapter 3
4
Does RAM or ROM store the BIOS?
5
Does RAM or ROM store the programs that are currently in use?
6
The data stored in ROM is fixed as it does not normally change.
Is this statement true or false?
7
It is easy to upgrade the amount of RAM in a computer by just installing more.
Is this statement true or false?
8
Why does a computer system need both RAM and ROM?
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Chapter 3
9
Storage can be magnetic, optical, or solid state.
Tick (✔) to show whether the statement about magnetic storage is true or false.
Magnetic storage
True (✔)
False (✔)
Uses lasers to create pits and lands on the surface of a disk
Data is stored on platters that are divided into tracks and sectors
An HDD is a type of magnetic storage
Uses transistors and control gates and floating gates
Has a read/write head that is moved across circular plates to read/write data
10 How does solid state storage operate to store data?
11 How is data written to and read from a CD?
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Chapter 3
Exercise 2
Virtual memory
Computers sometimes use a type of memory called virtual memory. This allows the computer to continue processing data
when the RAM is full.
1
Draw a diagram that shows how virtual memory operates.
2
What would happen if RAM was full and a computer didn’t have virtual memory that could be used?
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Chapter 3
Exercise 3
Cloud storage
Cloud storage is another way to store data. Physical servers and storage devices are still used to store data in the cloud, but these
belong to a third party, rather than the individual or company that owns the data.
1
In a cloud storage system is data stored locally or remotely?
2
List two benefits of storing data in a cloud storage system.
1
2
3
List two drawbacks of storing data in a cloud storage system.
1
2
3.4 Network hardware
A network is two or more devices that have been connected using a wired or wireless connection. A range of hardware is
required to create a network.
Exercise 1
1
Components
(a) What is the name of the component in a computer that connects the computer to a network?
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Chapter 3
(b) What is the name of the address given to this component at the manufacturing stage?
2
Is a MAC address usually written in binary, hexadecimal or denary?
3
How is a MAC address usually created?
4
(a) What is the name of the network component that reads data packets and forwards them to the correct destination?
(b) This component uses an Internet Protocol (IP) address to forward the data packets to the correct destination.
(i) What is the purpose of an IP address?
(ii) Can you give three features of an IP address?
1
2
3
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Chapter 3
Revision checklist
Need to revisit
Satisfactory
Confident
I understand the role of the central processing unit (CPU) in a
computer
I understand what is meant by a microprocessor
I understand the purpose of the components in a CPU, in a computer
that has a von Neumann architecture
I can describe the process of the fetch-decode-execute cycle
including the role of each component in the process
I understand what is meant by a core, cache and clock in a CPU and
can explain how they can affect the performance of a CPU
I understand the purpose and use of an instruction set for a CPU
I can describe the purpose and characteristics of an embedded
system and identify devices in which they are commonly used
I can identify a range of different input and output devices
I understand what is meant by an input device and why it
is required
I understand what is meant by an output device and why it is
required
I understand what is meant by a sensor and the purposes of sensors
I can identify the type of data captured by each sensor and
understand when each sensor would be used, including selecting
the most suitable sensor for a given context
I understand what is meant by primary storage
I understand what is meant by secondary storage
I can describe the operation of magnetic, optical and solid state (flash
memory) storage and give examples of each
I can describe what is meant by virtual memory, how it is created and
used, and why it is necessary
I understand what is meant by cloud storage
I can explain the advantages and disadvantages of storing data on
the cloud in comparison to storing it locally
I understand that a computer needs a network interface card (NIC) to
access a network
I understand what is meant by and the purpose of a Media Access
Control (MAC) address, including its structure
40
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Chapter 3
I understand what is meant by and the purpose of an Internet
Protocol (IP) address
I understand that there are different types of IP address
I can describe the role of a router in a network
Hardware
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Cambridge IGCSETM
Computer Science
For over 60 years Marshall Cavendish Education has been
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The Marshall Cavendish Education Cambridge IGCSETM Computer Science series
is designed for students studying for the Cambridge IGCSE and IGCSE (9–1)
Computer Science syllabuses (0478/0984). The series focuses on developing
important computer science skills relevant to real-world applications.
Cambridge
IGCSE
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Computer Science
WB The Workbook follows the same flow and structure as the Student’s Book and provides supplementary
exercises for students to reinforce concepts learnt during lessons and familiarise themselves with the
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of concepts.
✓ Provides learner support for the Cambridge
IGCSE and IGCSE (9–1) Computer Science syllabuses
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WORKBOOK
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WORKBOOK
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