ZNOTES.ORG
UPDATED TO 2023-2025 SYLLABUS
CAIE IGCSE
ICT
SUMMARIZED NOTES ON THE THEORY SYLLABUS
Prepared for Harish Kishore for personal use only.
,CAIE IGCSE ICT
4. Utilities: A system software that provides the
necessary facilities (Antivirus, Scan Disk, Disk
1. Types and Components of Defragmentation, etc.)
5. Operating systems: To enable computer
Computer Systems systems to function and allow users to
communicate with computer systems, special
1.1. Hardware & Software software, known as operating systems (OS),
have been developed.
Hardware
Analogue and Digital Data
the electronic, physical components that make up a
Computers can only understand data in the form of binary
typical computer system. These may include input and
digits (0,1); this is commonly known as digital data. However,
output devices as well.
data in the real world is analogue, not limited to two specific
Internal Hardware Devices:
values.
Central processing unit
Processor
Motherboard
Internal memory consisting of RAM & ROM
Graphics & Sound Cards
Internal Storage devices like Hard disk drives (HDD)
and solid-state drives (SSD)
Network interface card (NIC)
External Hardware Devices:
Monitor
Keyboard
Mouse
Printer
External Storage Devices
Software
The techniques, methods, commands, and instructions tell
the device what to do and how to do it. They are the
programs that control the computer system and process
data.
Relates to ideas & instructions for using physical objects. The figures show how data changes in analogue and
digital forms; analogue data forms smooth curves,
Two types of software: whereas digital data changes in discrete steps.
So, for a computer to process real-world data, it first
Application software:
needs to convert the received data into digital form. This
Provides services that allow the user to do specific
is done by hardware known as ADC (analogue to digital
tasks.
converter), and its output is given back in analogue form
It can be general-purpose software or custom-made
using DAC (digital to analogue converter).
software. (Specialist software)
E.g., Spreadsheets, databases, and word processors.
System Software: 1.2. The Main Components of Computer
The software is designed to provide a platform all Systems
other software can run. For example:
1. Compilers: The software translates the High-
Central Processing Unit (CPU)
level language into Machine code (Language
Processor). The component of the computer that understands and
2. Linkers: A Software that creates the links executes hardware and software operations. Nowadays,
between Language processors into workable it’s also known as a microprocessor. It is a single
solutions (Data definition language). integrated circuit at the core of most PCs and is also
3. Device drivers: A software that enables the present in many household gadgets and equipment
device to work with another, externally where some control or monitoring is required.
connected device.
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
,CAIE IGCSE ICT
It consists of a control unit (CU) that manages the input Backing and Secondary Storage
and output devices, an arithmetic and logic unit (ALU) that
performs computations and makes logical judgments, and Required to store significant amounts of data
tiny memory regions known as registers. permanently.
It processes the input and produces the outcome of the Most commonly in the form of Hard disk drives and Solid-
processing in the form of output. state drives.
Internal Memory Differentiating between internal memory and backing
storage:
1. Random access memory (RAM): temporary memory
1. RAM contents are lost when power is lost, ROM is
storage, lost after power is shut down, performs read
read-only, and backing storage is permanent even
and write functions, is used to store data that are
without power.
currently in use, and can be increased in size to
2. RAM and ROM are much smaller than backing
improve operational speed.
2. Read-only memory (ROM): permanent memory storage.
3. RAM and ROM are significantly faster in accessing
storage, non-volatile, can only be read from, used to
data than backing storage.
store computer’s configuration data, such as BIOS.
4. Backing storage is much cheaper than internal
N.B: The BIOS (basic input/output memory.
system) stores the date, time and 5. Internal memories are fixed, and backing storage can
system configuration on a non-volatile be fixed or portable.
chip called a CMOS (complementary 6. Internal memories can be directly read by the CPU,
metal oxide semiconductor) – this is while backing storage needs to be moved into the
usually battery powered. RAM before being read by the CPU.
Differentiating between Internal memories:
1.3. Operating Systems
1. RAM is a temporary memory device, whereas ROM is
a permanent one. Controls operation of input, output & backing storage
2. RAM is volatile, ROM is non-volatile. Supervises loading, running & storage of application
3. RAM can be written to and from, but ROM can only be programs.
read from. Deals with errors in application programs.
4. RAM is used to store data, files, programs, and parts Maintains security of the whole computer system
of OS that are currently in use. However, ROM is used Maintains a computer log.
in storing start-up data,
Operating systems offer various types of user interfaces, for
example:
Input & Output Devices
1. Command line interface: user needs to type in
Input devices are pieces of hardware that allow users to commands to communicate with the computer. The
enter data into computers.
user is in direct communication with the computer.
An output device displays the computer's output in a Not restricted to pre-defined options. Possible to alter
human-readable format. For example, words on a printer computer configuration settings. Needs to learn many
or moving graphics on a monitor. commands for basic operations. All commands need
to be typed in, which is time-consuming. Very error
Input devices Output devices
prone, as commands must have correct format,
An input device is any An output shows the result or spelling etc.
hardware that enables data solution of the input after it N.B: Mainly used by programmers who need to have
entry. has been processed. direct communication with the computer.
An input device can only send An output device can only 2. Graphical user interface: Uses WIMP (windows icons
data. receive data. menu and pointing device). The user does not need to
Input devices are necessary Output devices are needed in learn any commands. It is more user-friendly; icons
for a computer to receive order to display the outcome are used to represent applications. A pointing device
commands from the user for of the processing that took is used to click on an icon to launch the application,
processing to be permitted. place to the user. this is simpler than typing in commands. This type of
interface uses up considerably more computer
Input devices are complex as
Output devices are simpler as memory than a CLI interface. The user is limited to the
they must ensure proper
they only need to display the icons provided on the screen. Needs a more complex
communication between the
finale. operating system.
computer and the user.
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
, CAIE IGCSE ICT
N.B: Mainly used by end-users who don’t have great up the desk space.
knowledge of how the computer works. 3. Because they aren’t portable, files must be copied
3. Dialogue-based user interface: use the human voice to another portable storage device to take work
to give commands to a computer system. no need for elsewhere.
a driver to take their hands off the steering wheel. In a
home, it is especially useful for people with disabilities Mobile Computers
because many tasks can be carried out by the spoken
word only. Possible to use it as a security feature 1. Laptop computer:
because voice recognition could be used to identify a
person. Still unreliable, with many commands not (Or notebook) refers to a type of computer where the
being recognized or needing to be repeated several monitor, keyboard, pointing device and processor are all
times (especially if there is background noise). Can be together in one unit. This makes them extremely portable.
quite complex to setup. User needs to know which lightweight (to aid portability). Low power consumption
commands can be used. (and also long battery life). Low heat output (cooling is
4. Gesture-based user interface: relies on human very important).
interaction by the moving of hands, head or even feet. Uses:
Replaces mechanical input devices. No physical 1. office and business work
contact is required. Very natural interface for a human 2. educational use
operator. No training is needed to interface with the 3. used as a gaming device.
computer. It is possible for unintentional movement to 4. general entertainment
be picked up. Only works near the camera or sensor Advantages:
(maximum of 1.5 meters). May only accept a limited 1. Portability: all components are in a single unit, so
number of movements (for example, it may take they can be taken anywhere.
several attempts to determine exactly what finger 2. Because of one single unit, there are no trailing
movements are recognized). wires and desk clutter.
3. take up much less room on a desk, so they can be
easily used in public spaces.
1.4. Types of Computers 4. portability allows them to take full advantage of
Wi-Fi features.
Desktop Computers
Disadvantages:
1. portability makes it easier for them to be stolen.
Desktop usually refers to a general-purpose computer
2. limited battery life means the user needs to carry
that is made up of a separate monitor, keyboard, mouse,
a charger at all times.
and processor unit. It is distinguished from, for example, a
3. keyboards and pointing devices may be awkward
laptop computer by the fact that it is made up of several
to use.
separate components, which makes it not very portable.
4. not easy to upgrade, like adding more RAM.
Uses:
1. office and business work
2. Smartphones:
2. educational use
3. general entertainment
Allow normal phone calls to be made, but also have an
4. gaming device
operating system (such as iOS, Android, or Windows),
Advantages: allowing them to run a number of computer applications
1. They are easier and less costly to upgrade and
(known as apps or applets). Smartphones communicate
expand.
with the internet either by using Wi-Fi hot spots or by
2. Spare parts are standardized, which makes them
using 3G/4G/5G mobile phone networks.
cheaper.
Uses:
3. They tend to have better specifications for a given
1. They allow users to send/receive emails.
price.
2. They allow users to use a number of apps.
4. No critical power consumption because they plug
3. They allow users to use a camera feature (to take
into a wall socket.
photos or videos).
5. Due to fixed positions, they are less likely to be
4. They allow users to use an MP3/4 player (for music
damaged or stolen. and videos).
6. As they usually have wired connections, they have
Advantages:
more stable internet access.
1. very small in size and lightweight, makes them
Disadvantages:
portable.
1. They are not particularly portable because they
2. connecting to the internet while on the move.
are made up of separate components. 3. because they use Wi-Fi and mobile phone
2. More complicated because all the components
networks, they can be used almost anywhere.
need to be hooked up by wiring, which also clutters
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
UPDATED TO 2023-2025 SYLLABUS
CAIE IGCSE
ICT
SUMMARIZED NOTES ON THE THEORY SYLLABUS
Prepared for Harish Kishore for personal use only.
,CAIE IGCSE ICT
4. Utilities: A system software that provides the
necessary facilities (Antivirus, Scan Disk, Disk
1. Types and Components of Defragmentation, etc.)
5. Operating systems: To enable computer
Computer Systems systems to function and allow users to
communicate with computer systems, special
1.1. Hardware & Software software, known as operating systems (OS),
have been developed.
Hardware
Analogue and Digital Data
the electronic, physical components that make up a
Computers can only understand data in the form of binary
typical computer system. These may include input and
digits (0,1); this is commonly known as digital data. However,
output devices as well.
data in the real world is analogue, not limited to two specific
Internal Hardware Devices:
values.
Central processing unit
Processor
Motherboard
Internal memory consisting of RAM & ROM
Graphics & Sound Cards
Internal Storage devices like Hard disk drives (HDD)
and solid-state drives (SSD)
Network interface card (NIC)
External Hardware Devices:
Monitor
Keyboard
Mouse
Printer
External Storage Devices
Software
The techniques, methods, commands, and instructions tell
the device what to do and how to do it. They are the
programs that control the computer system and process
data.
Relates to ideas & instructions for using physical objects. The figures show how data changes in analogue and
digital forms; analogue data forms smooth curves,
Two types of software: whereas digital data changes in discrete steps.
So, for a computer to process real-world data, it first
Application software:
needs to convert the received data into digital form. This
Provides services that allow the user to do specific
is done by hardware known as ADC (analogue to digital
tasks.
converter), and its output is given back in analogue form
It can be general-purpose software or custom-made
using DAC (digital to analogue converter).
software. (Specialist software)
E.g., Spreadsheets, databases, and word processors.
System Software: 1.2. The Main Components of Computer
The software is designed to provide a platform all Systems
other software can run. For example:
1. Compilers: The software translates the High-
Central Processing Unit (CPU)
level language into Machine code (Language
Processor). The component of the computer that understands and
2. Linkers: A Software that creates the links executes hardware and software operations. Nowadays,
between Language processors into workable it’s also known as a microprocessor. It is a single
solutions (Data definition language). integrated circuit at the core of most PCs and is also
3. Device drivers: A software that enables the present in many household gadgets and equipment
device to work with another, externally where some control or monitoring is required.
connected device.
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
,CAIE IGCSE ICT
It consists of a control unit (CU) that manages the input Backing and Secondary Storage
and output devices, an arithmetic and logic unit (ALU) that
performs computations and makes logical judgments, and Required to store significant amounts of data
tiny memory regions known as registers. permanently.
It processes the input and produces the outcome of the Most commonly in the form of Hard disk drives and Solid-
processing in the form of output. state drives.
Internal Memory Differentiating between internal memory and backing
storage:
1. Random access memory (RAM): temporary memory
1. RAM contents are lost when power is lost, ROM is
storage, lost after power is shut down, performs read
read-only, and backing storage is permanent even
and write functions, is used to store data that are
without power.
currently in use, and can be increased in size to
2. RAM and ROM are much smaller than backing
improve operational speed.
2. Read-only memory (ROM): permanent memory storage.
3. RAM and ROM are significantly faster in accessing
storage, non-volatile, can only be read from, used to
data than backing storage.
store computer’s configuration data, such as BIOS.
4. Backing storage is much cheaper than internal
N.B: The BIOS (basic input/output memory.
system) stores the date, time and 5. Internal memories are fixed, and backing storage can
system configuration on a non-volatile be fixed or portable.
chip called a CMOS (complementary 6. Internal memories can be directly read by the CPU,
metal oxide semiconductor) – this is while backing storage needs to be moved into the
usually battery powered. RAM before being read by the CPU.
Differentiating between Internal memories:
1.3. Operating Systems
1. RAM is a temporary memory device, whereas ROM is
a permanent one. Controls operation of input, output & backing storage
2. RAM is volatile, ROM is non-volatile. Supervises loading, running & storage of application
3. RAM can be written to and from, but ROM can only be programs.
read from. Deals with errors in application programs.
4. RAM is used to store data, files, programs, and parts Maintains security of the whole computer system
of OS that are currently in use. However, ROM is used Maintains a computer log.
in storing start-up data,
Operating systems offer various types of user interfaces, for
example:
Input & Output Devices
1. Command line interface: user needs to type in
Input devices are pieces of hardware that allow users to commands to communicate with the computer. The
enter data into computers.
user is in direct communication with the computer.
An output device displays the computer's output in a Not restricted to pre-defined options. Possible to alter
human-readable format. For example, words on a printer computer configuration settings. Needs to learn many
or moving graphics on a monitor. commands for basic operations. All commands need
to be typed in, which is time-consuming. Very error
Input devices Output devices
prone, as commands must have correct format,
An input device is any An output shows the result or spelling etc.
hardware that enables data solution of the input after it N.B: Mainly used by programmers who need to have
entry. has been processed. direct communication with the computer.
An input device can only send An output device can only 2. Graphical user interface: Uses WIMP (windows icons
data. receive data. menu and pointing device). The user does not need to
Input devices are necessary Output devices are needed in learn any commands. It is more user-friendly; icons
for a computer to receive order to display the outcome are used to represent applications. A pointing device
commands from the user for of the processing that took is used to click on an icon to launch the application,
processing to be permitted. place to the user. this is simpler than typing in commands. This type of
interface uses up considerably more computer
Input devices are complex as
Output devices are simpler as memory than a CLI interface. The user is limited to the
they must ensure proper
they only need to display the icons provided on the screen. Needs a more complex
communication between the
finale. operating system.
computer and the user.
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
, CAIE IGCSE ICT
N.B: Mainly used by end-users who don’t have great up the desk space.
knowledge of how the computer works. 3. Because they aren’t portable, files must be copied
3. Dialogue-based user interface: use the human voice to another portable storage device to take work
to give commands to a computer system. no need for elsewhere.
a driver to take their hands off the steering wheel. In a
home, it is especially useful for people with disabilities Mobile Computers
because many tasks can be carried out by the spoken
word only. Possible to use it as a security feature 1. Laptop computer:
because voice recognition could be used to identify a
person. Still unreliable, with many commands not (Or notebook) refers to a type of computer where the
being recognized or needing to be repeated several monitor, keyboard, pointing device and processor are all
times (especially if there is background noise). Can be together in one unit. This makes them extremely portable.
quite complex to setup. User needs to know which lightweight (to aid portability). Low power consumption
commands can be used. (and also long battery life). Low heat output (cooling is
4. Gesture-based user interface: relies on human very important).
interaction by the moving of hands, head or even feet. Uses:
Replaces mechanical input devices. No physical 1. office and business work
contact is required. Very natural interface for a human 2. educational use
operator. No training is needed to interface with the 3. used as a gaming device.
computer. It is possible for unintentional movement to 4. general entertainment
be picked up. Only works near the camera or sensor Advantages:
(maximum of 1.5 meters). May only accept a limited 1. Portability: all components are in a single unit, so
number of movements (for example, it may take they can be taken anywhere.
several attempts to determine exactly what finger 2. Because of one single unit, there are no trailing
movements are recognized). wires and desk clutter.
3. take up much less room on a desk, so they can be
easily used in public spaces.
1.4. Types of Computers 4. portability allows them to take full advantage of
Wi-Fi features.
Desktop Computers
Disadvantages:
1. portability makes it easier for them to be stolen.
Desktop usually refers to a general-purpose computer
2. limited battery life means the user needs to carry
that is made up of a separate monitor, keyboard, mouse,
a charger at all times.
and processor unit. It is distinguished from, for example, a
3. keyboards and pointing devices may be awkward
laptop computer by the fact that it is made up of several
to use.
separate components, which makes it not very portable.
4. not easy to upgrade, like adding more RAM.
Uses:
1. office and business work
2. Smartphones:
2. educational use
3. general entertainment
Allow normal phone calls to be made, but also have an
4. gaming device
operating system (such as iOS, Android, or Windows),
Advantages: allowing them to run a number of computer applications
1. They are easier and less costly to upgrade and
(known as apps or applets). Smartphones communicate
expand.
with the internet either by using Wi-Fi hot spots or by
2. Spare parts are standardized, which makes them
using 3G/4G/5G mobile phone networks.
cheaper.
Uses:
3. They tend to have better specifications for a given
1. They allow users to send/receive emails.
price.
2. They allow users to use a number of apps.
4. No critical power consumption because they plug
3. They allow users to use a camera feature (to take
into a wall socket.
photos or videos).
5. Due to fixed positions, they are less likely to be
4. They allow users to use an MP3/4 player (for music
damaged or stolen. and videos).
6. As they usually have wired connections, they have
Advantages:
more stable internet access.
1. very small in size and lightweight, makes them
Disadvantages:
portable.
1. They are not particularly portable because they
2. connecting to the internet while on the move.
are made up of separate components. 3. because they use Wi-Fi and mobile phone
2. More complicated because all the components
networks, they can be used almost anywhere.
need to be hooked up by wiring, which also clutters
WWW.ZNOTES.ORG Copyright © 2024 ZNotes Education & Foundation. All Rights Reserved. This document is authorised
for personal use only by Harish Kishore at Mahatma Global Gateway (CAIE) on 12/05/24.
