0417 IGCSE ICT Chapter 1

2016 © Provided by Anthi Aristotelous
1
Chapter 1
Types and Components of Computer Systems
Pages 2 - 7

2017 © Provided by Anthi Aristotelous 2
What is a computer?
• Computers are machines which help us perform
tasks efficiently.
• Computers are involved in the manipulation of
data and the words ‘data’ and ‘information’ are
used interchangeably.
INPUT PROCESS OUTPUT
STORAGE

What is Hardware?
• Hardware refers to the PHYSICAL components
of a computer system; i.e. those things which
can be touched.
• Hardware includes:
– Processor
– Video cards
– Motherboards
– Internal hard disk drives
– Read-only Memory (ROM)
– Random Access Memory (RAM)

System Unit
• The system unit (also
called Tower) is where all
the computer components
are stored. It is the main
part of a Personal
Computer.
• It contains the:
– Motherboard
– CPU
– Memory
– Internal hard disk
– and more…

The Motherboard
• It is the main circuit board of a
micro-computer.
• Connects all the different
components to each other thus
allowing them to communicate
with each other.
• Connects the:
– CPU
– RAM
– and all other devices…

Processor
• CPU (Central Processing Unit)
can be considered to be the
brain of the computer where
most calculations take place.
• It determines the speed of the
computer, and it performs all the
major functions of the computer.
• The CPU speed is measured in
Gigahertz (Ghz).
• The CPU is inserted directly into
a CPU socket, pin side down on
the motherboard.

Processor
• Consists of two components: CU and ALU
• The Control Unit (CU) is responsible to perform control
operations, where data is send/received within the computer.
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• Arithmetic Logic
Unit (ALU) is
responsible to perform
mathematical
calculations among
numbers and make
logical decisions
(AND, OR, NOT).

RAM (Random Access Memory)
• A type of computer memory, where
data is temporarily stored when
applications are running
• Data can be written to and read
from and it is often described as
‘read/write’ memory.
• It is VOLATILE (when the computer
is switched off ALL is lost).
• Stores the data, files or part of OS
currently in use.

RAM – Random Access Memory
• When you want to use a program, you instruct the
system to load the program required. In a matter of
seconds, the computer reads the program from the disk
and loads (copies) it to the RAM.
• If the computer is switched off, the contents of the RAM
will be lost. For this reason RAM is called a volatile
memory. So any information which is in the RAM and
needs to be stored permanently must be stored in the
hard disk.

ROM (Read Only Memory)
• Is a computer memory which data
can be pre-recorded (by
manufacturer)
• Once data has been written, it
cannot be altered or removed.
• Non-volatile, all data will remain
intact when computer is turned
off.
• Contains BIOS (basic input
output system) which is executed
when the computer is turned on.

ROM – Read Only Memory
• ROM refers to chips that have a series of instructions
built into them by the manufacturer.
• The ROM chip retains important instructions in a
permanently accessible, non-volatile form and which
cannot be overwritten.
• When the computer is switched off, the contents of the
ROM are not lost.

Video cards
• Also known as video adapter or
graphics card.
• Can be an expansion card (or in-
build) which allows the computer
to send graphic information to a
display device.
• Usually contains a cooling
mechanism, heat sink and
connections to a display unit.
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VGA
DVI

Sound cards
• Also known as an audio
card.
• Is an internal circuit board
which produces input and
output audio signals.
• Sound cards allow the user
to record, input sound via a
microphone. Manipulate
sounds stored on a disk for
multimedia applications.
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speakers
microphone

Internal hard disc drive
and solid state drive
• Hard disk drive (HDD) and Solid state drive (SSD) are data
storage devices used for storing and retrieving digital
information.
• They are used for storing booting instructions, Operating
System, software applications and other personal files.
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HDDSSD

Comparison between hard drives
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Hardware devices and peripherals
A peripheral device is any equipment that is externally
connected to the system unit such as: keyboard, printer,
mouse, monitor, speakers, etc…
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System unit
Memory stick
External
hard
drive
Speakers
Keyboard
Mouse
monitor
Printer

Input, Output and Storage Devices
INPUT
OUTPUT
STORAGE
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Memory
stick
External
hard drive
Speakersmonitor Printer
Keyboard Mouse microphoneWeb camera scanner
Projector Headphones
Internal
hard drive
Flash memory
cards
CD, DVD,
blu-ray

Difference between input and output
devices
An input device sends data to a computer system for
processing, where as an output device reproduces or displays
the results of the processing.
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scanner
keyboard
mouse
Barcode
reader
Light
Pen
Joystick
trackball
INPUT OUTPUTBOTH
Graph plotter
speakers
Inkjet
printer
Touchscreen
monitor
Headset
Modem
Digital camera
Fax
Web camera
projector
Dot-matrix
Laser
printer
headphones
monitor

What is Software?
• Software, also known as programs, are a set of
instructions that make the computer work.
• Software is divided into 2 main categories:
– system software
– application software

System Software
• System Software, is also known as Operating System. It
allows the user to control the operation of a computer
system.
• Without OS, computers would not be easily usable by
users.

DOS
Disk Operating System is one of the earliest Operating
Systems. User who operated it had to remember commands!
MS-DOS dominated in 1980s.

OS Features
• Provides a platform to run application software
• Allows communication between the user and the computer (use of
HCI)
• Allows to manage the security (user accounts, password protection)
• Enables hardware to communicate with OS
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OS
User Interface
SecurityMulti-tasking
Peripheral
Management
Memory
Management

System software
• Compiler is a computer program that translates source code
written in a programming language into binary, also known as
object code or machine language.
• A linker is a computer program that takes one or more object
files generated by a compiler and combines them into a single
executable file, library file that can run on a computer.
• Device driver is a program that enables a particular device
which is connected to a computer, to communicate with the
operating system.
• Utility software are software that have been designed to carry
out specific tasks to help configure, optimize or maintain a
computer system.
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Application Software
• Application software are programs that allow the
user to perform specific tasks.
• Examples of application software are:
– Word processor
– Spreadsheet
– Database
– Control and measuring software
– Photo editing software
– Video editing software
– Graphics manipulation software
– Apps
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Examples of Application Software
• Word Processing: used to manipulate text documents,
such as letters or reports. Provides tools for inserting
photos/images, chancing text formatting, spell checking
and mail merging.
• Spreadsheet: used for organising and manipulating
numerical data. These numbers are organised in a grid
of cells. Can use formulas to carry out calculations,
produce graphs and it is also used for modelling and
predictions.
• Database: Helps to organise, manipulate and analyse
large quantities of data. Provides the ability to carry out
queries and produce reports. Also enables to add,
delete and modify data in a table.

• Presentation: Used for displaying information if the
form of slide show. Enables to manipulate text,
inserting graphics or audio. Include animations and
slide transitions to keep audience attention.
• Desktop Publisher (DTP): Used for designing flyers,
invitations, posters, reports, magazines and books.
Includes in-build themes/layout structures, that are
editable.
• Control and measuring software: are designed to
allow a computer or microprocessor control devices to
measure physical variables in the real world and
control applications.
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• Photo editing software: Allows to manipulate digital
photographs stored on a computer or any other
external device. Can change brightness, contrast,
saturation and can also combine photos.
• Video editing software: Can manipulate videos to
produce an edited video, by adding titles, altering
sounds of frames. Also can colour correct and include
transitions between clips.
• Graphics manipulation software: Allows bitmap and
vector images to be manipulated.
• Apps, also known as applications, normally refers to
the applications running on mobile devices, such as
phones or tablets.
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1.2 Quiz Time!!!
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1.3 Operating Systems
Pages 8 - 9

User Interfaces
• The user interface (UI) is the industrial design which
enables a human to interact with a machine/computer using
a display screen, keyboard or mouse.
• There are two type of interfaces:
– Command Line Interface (CLI)
– Graphical user Interface (GUI)
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Command Line Interface (CLI)
• CLI, is also known as command language interpreter or
console user interface.
• The user (technician or programmer) can only interact with
the system and perform operations when commands are
typed.
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Graphical User Interface (GUI)
• Allows the end user to interact with the computer clicking on
icons, rather than typing commands.
• It uses WIMP technology
– windows
– icons
– menu
– pointer

CLI vs GUI
Command line interface
 User has direct
communication with the
computer
 It is not restricted to a number
of predetermined options
 Can alter configuration
settings
 User must learn and
understand commands
 Commands must be typed in,
more prone to errors
Graphical user interface
 User doesn’t need to learn
commands
 It is more user-friendly and
can launch applications easily.
 It uses more computer
memory due to OS graphics
provided.
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1.4 Types of computers
Pages 9 - 14

PC/ Desktop computer
• PC (personal computer) usually
refers to a general purpose computer
that is made of a separate monitor,
keyboard, mouse and processor.
 They are relatively inexpensive
computers designed for the individual
users.
 They tend to be better specification
for a given price, compared to
laptops.
 They are fixed to one location, so less
likely to loss internet connection.

Types of Computers
• The Macintosh, also known
as Mac’s are a series of
personal computers designed
and developed by Apple Inc.
• They use a different
operating system called
Mac/OS.
• These computers are usually
used by graphic designers
and video editors are they
are advertised for their
distinguished graphics.

Laptop computers
• Laptop computer refers to the type of computer where the
monitor, keyboard, pointing device and processor are all
together in a single unit.
• A portable computer, which is suitable for carrying around
while travelling. They are usually battery powered and small
size.

Tablets
• Tablets are a recent device
produced to enable internet
activities on this portable handheld
device.
• They use touch-screen technology
(hence no keyboard is required) or
a stylus.
• They can access the internet using
WIFI or 4G/5G mobile connectivity.
• They are equipped with sensors,
front and rear cameras, Bluetooth
and some devices even support
flash memory

Smartphones
• Smartphone is a mobile phone that performs many
functions of a computer and allows to make phone
calls. The difference with a typical mobile phones is
that it has an operating system.
• Allows to run a number of apps for different
purposes, such music and video streaming, instant
access to social networking, etc..
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Smartwatches
• Smartwatches give the ability to users to wear a
mini-computer on their wrists.
• They use touchscreen technology, and some also
have the ability to link using Bluetooth technology.
• They allow internet connectivity, phone calls, texts,
health monitoring and GPS.
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Mainframe computers
• Mainframe computer is a large and
powerful computer system capable of
great processing speeds and data
storage.
• Their purpose is to run commercial
applications, such as banking,
government and airline data.
• They that can support many users at
the same time.
• They have several CPUs, can support
multiple OS and have huge amount of
memory and storage capacity.

Comparing Computer Types
+ Cost +Speed +Storage
•Mainframe
•PCs
–Desktop
–Laptop
•Smartphone
•Smartwatch
- Cost - Speed - Storage

1. 4 Quiz Time!!!
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1.5 Impact of emerging
technologies
Pages 15 - 18

Artificial Intelligence
• Artificial intelligence (AI)
biometrics is a system that uses
fingerprint identification or facial
recognition to verify a person.
• A person’s finger prints are
scanned using specialized
equipment and compared in a
database.
• AI technologies are being
developed and improved, so they
can be embedded in security
systems as they more reliable.
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Vision enhancement
• Low-vision enhancement (LVES) allows images to be
projected inside a headset using video technology
connected to a computer. Allows user to view and
examine objects closer.
46

Vision enhancement
• Night vision enhancement (NVE) has the ability to
enhance and view an image in low light conditions, such
when there is darkness.
• Military use this technology for surveillance at night.
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Robotics
• Robotics is a field of mechanical/ electrical engineering
which deals with design, construction, operation and
application of robots.
• Used in car factories to weld car bodies, spray panels
and fit items. Another application is use for drones
which can be used for search and rescue. Also used for
complex surgical procedures to improve precision and
flexibility control.
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Quantum cryptography
• Cryptography is the practise and techniques for secure
communication between parties, where a message is
unreadable by unauthorised users (hackers). Also referred
as encryption.
• Quantum cryptography use photons and their physical
quantum properties produce a virtually unbreakable system.
Improves protection of security of data. Relies that the
photons oscillate in different directions and produce random
0s and 1s.
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Example of key distribution

Computer-assisted
translation (CAT)
• Computer-assisted translation (CAT): is a type of
language translation where a human translator, uses a
computer software to help the translation process.
• They mainly use two tools:
• Terminology management software: are linguistic
databases that grow and ‘learn’ as translations are being
carried out
• Translation memory software: they automatically insert
from previously stored translations for specific words,
phrases or sentences.
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Computer-assisted translation
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3-D and holographic imaging
• Holography is the science of making holograms and
displaying a 3-D images. It is an encoding of the laser light,
as an interference pattern which diffracts into a reproduction
of the original.
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3-D
• Is the process of developing a mathematical representation
of any three dimensional surface of an object.
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3D modelling 3D printer

Virtual reality
• Virtual reality is a computer
generated of a three-dimensional
artificial environment that can be
interacted with in a seemingly real
or physical way by a person with
the use of electronic equipment.
• User uses equipment such as data
goggles, sensor suits, data gloves
or helmets.
• Used in military training,
education, games ect.
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0417 IGCSE ICT Chapter 1

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