Chapter 1
Types and Components of Computer Systems
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.
STORAGE
INPUT
PROCESS
OUTPUT
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What
WhatisisaHardware?
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)
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What
System
System
is a
Unit
computer?
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…
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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…
5
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.
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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.
• Arithmetic Logic Unit (ALU)
is
responsible to perform mathematical
calculations among
numbers and
make logical decisions (AND, OR,
NOT).
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Internal Memory - RAM (Random
Access Memory)
• The main memories of a computer system are RAM &
ROM.
• 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.
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Internal Memory - 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.
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Internal Memory - ROM (Read Only Memory)
• Is a computer memory which data
recorded (by manufacturer)
can be pre-
• Once data has been written, it
cannot be altered or removed.
• Non-volatile, all data will remain
computer is turned off.
intact when
• Contains BIOS (basic input output system) which
is executed when the computer is turned on.
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Internal Memory - 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.
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Video cards
• Also known as video adapter or
graphics card.
• Can be an expansion card (or inbuild) 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.
DVI
VGA
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Sound cards
speakers
microphone
• 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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Backing Storage - Internal hard disc drive and
solid state drive
• To permanently store large amount of data it is necessary to use backing storage.
• This normally takes the form of the internal HDD or SSD.
• 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
applications and other personal files.
System, software
HDD
SSD
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Comparison between hard drives
15
Comparison Between Internal Memory & Backing
Storage
Internal Memory
RAM contents are lost when computer is powered
down; ROM contents are readable only
Backing Storage
Backing devices holds their contents permanently even
when powered down.
RAM and ROM are much smaller memories than backing Have considerably larger capacity to store data than
storage .
RAM and ROM.
Data access time on RAM and ROM is extremely fast.
Has much slower data access time than RAM and ROM.
Much ore expensive per byte than backing storage
device.
Is much cheaper per byte than RAM or ROM
RAM and ROM are fixed inside the computer (Internal
memories)
Backing storage can either be fixed (external or internal)
or it can be removable
RAM and ROM can be read directly by the CPU.
Before data on a backing storage device can be read by
the CPU. It must be moved into RAM; this means
backing storage is not directly addressable by the CPU.
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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…
Memory stick
monitor
Speakers
System unit
Keyboard
External
hard
drive
Mouse
Printer
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Input, Output and Storage Devices
INPUT
Keyboard
Mouse
Web camera
Speakers
Printer
microphone
scanner
OUTPUT
monitor
Projector
Headphones
STORAGE
Memory
stick
External
hard drive
Internal
hard drive
CD, DVD,
blu-ray
Flash memory
cards
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.
BOTH
INPUT
trackball
scanner
OUTPUT
speakers
Digital camera
monitor
Modem
mouse
Dot-matrix
keyboard
Graph plotter
Touchscreen
monitor
Web camera
Inkjet
printer
Barcode
reader
Light
Pen
Joystick
projector
Fax
Headset
Laser
printer
headphones
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.
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.
Application Software
• Application software are programs that allow the user to perform
specific tasks.
• Examples of application software are:
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–
–
–
–
–
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Word processor
Spreadsheet
Database
Control and measuring software
Photo editing software
Video editing software
Graphics manipulation software
– Apps
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.
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Examples of Application Software
• 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.
Examples of Application Software
• 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
running on mobile devices, such as phones or tablets.
the applications
1.2 Quiz Time!!!
Operating System & Its Features
User Interface
Peripheral
Management
Memory
Management
OS
Multi-tasking
Security
• OS is a master controlling program in a computer that controls all the connected devices
and organizes all the given tasks to make computer work efficiently on the behalf of a user.
• 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
DOS
Disk Operating System is one of the earliest Operating
operated it had to remember commands!
MS-DOS dominated in 1980s.
Systems. User who
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)
– Dialogue based User Interface
– Gesture based User Interface
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.
Graphical User Interface (GUI)
• Allows the end user to interact with the computer clicking on icons, rather than
typing commands.
• It uses WIMP technology
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–
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windows
icons
menu
Pointer
• In recent years, device such as touch screen smartphones and tablets use Post
–WIMP interaction, where fingers are in contact with the screen allowing action
such as pinching and rotating which is difficult to do using a single pointer and
device such as mouse.
Advantages a& Disadvantages of CLI & GUI
Graphical User Interface
(GUI)
Command Line
Interface (CLI)
Interface
Advantages
Disadvantages
The user is in direct communication with the The user needs to learn a number of commands to
computer.
carryout basic operations.
The user is not restricted to a number of pre- All commands needs to be typed in, which takes time and
determined options.
can be error prone.
It is possible to alter computer configuration Each command must be typed in using the correct format,
settings.
spelling and so on.
The user does not need to learn any commands.
This type of interface uses up considerably more
computer memory than a CLI.
It is more user friendly; icons are used to represent The user is limited to the icons provided on the screen.
applications.
A pointing device (such as a mouse) is used to click Needs a more complex operating system, such as
on an icon to launch the application – this is simpler Windows, to operate, which can be slower to execute
than typing commands.
commands.
Who would use each type of interface (CLI & GUI)?
CLI
A programmer, analyst or technician; basically somebody who needs to have a direct
communication with the computer to develop new software, locate errors and remove
them etc
GUI
The end user who does not have to (or does not need to) have any great knowledge
of how the computer works; a person who uses the computer to run software, play
games or store/manipulate photographs for example.
Dialogue based Interface
• Dialogue based User Interfaces use human voice commands to a computer system.
• Used in modern luxury cars, homes to control devices
• Examples : Amazon Alexa, Google Now, Apple Siri, Microsoft Cortana
Gesture based Interface
• Gesture based User Interfaces rely on human interaction by the moving of hands,
head or even the feet without any mechanical devices.
• This type of interface uses techniques known as computer vision and image
processing.
• Used in modern luxury cars, homes and offices to control devices etc
Advantages a& Disadvantages of CLI & GUI
Gesture-based Interface
Dialogue–based
Interface
Interface
Advantages
Disadvantages
No need for a driver to take their hands off the Still unreliable with many commands not being recognised
steering wheel
or needing to be repeated several times (especially if
there is background noise)
In a home, very useful for people with disabilities, Can be quite complex to set up
because many tasks can be carried out by the
spoken word only.
Possible to use as a security feature, because the User needs to know which commands to be used
voice recognition could be used to identify a person
Replaces mechanical input devices
Possible for unintentional movement to be picked up
No physical contact required
Only workers fairly near to the camera or sensor
(maximum of 1.5 meters)
Very natural interface for human operator
May only accept a limited number of movements (for
example, it may take several attempts to find out exactly
what finger movements are recognised)
No training needed to interface with the computer
Analogue and Digital Data
Digital Data
• Computers can only understand the data which is only in binary format. e.g.
(10101011)2
• 0 = 0 volt and 1 = 5 volts
• Based on discrete or discontinued values only.
• It is often referred to as “Digital Data”.
Analogue Data
• The real world data are the physical data which can be measured in quantities.
e.g temperature, wind speed, sound etc
• It changes from one value to another smoothly unlike digital data which either
shows 0 or it 5 volts. e.g. 11.29 →11.30 →11.31 →11.32 →11.31 →11.30
• Such physical data is called “Analogue Data”.
Analogue and Digital Data
 Digital Data/Signal
 Analogue Data/Signal
Analogue and Digital Data
ADC
• If analogue data is being sent to a computer, it must first be converted into digital
data. Say, from a microphone or a sensor to the computer
• This conversion is done by a hardware known as “Analogue to Digital
Convertor”.
DAC
• If a computer is controlling a device (such as a motor) then the digital output from
the computer needs to be converted into analogue form.
• It is done by “Digital to Analogue Convertor”.
Types of Computers: 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.
Smartwatches
• Smartwatches give the ability to users to wear a minicomputer 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.
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!!!
Emerging Technology: Impact of emerging technologies
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.
Extended Reality (XR)
• Extended Reality (XR) refer to real and
virtual combined environments, and is a
‘catch
all’ term
for
all impressive
technologies.
• The three most common examples are :
1. Augmented Reality (AR)
2. Virtual Reality (VR)
3. Mixed Reality (MR)
Features of Augmented Reality (AR)
• Allows user to experience the relationship between digital (virtual) and physical
(real worlds)
• Virtual information and objects are overlaid onto real-world situations.
• The real world is enhanced with digital details, such as images, text and
animation.
• The user can experience the AR world through special goggles or via smart
phone/phablets screens.
• The user is not isolated from the real world and is still able to interact and see
what is going on in front of them.
• Example include the Pokémon Go game which overlays digital creatures onto
real-world situations.
The impact of Augmented Reality (AR) in future on the areas
•
•
•
•
Safety and rescue operations
Entertainment
Shopping and retails (experiencing an item before buying it)
Healthcare (for understanding better the body of a patient by building up 3D
images before surgery)
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 etc.
Features of Virtual Reality (VR)
• The ability to take the user out of the real-world environment into a virtual
(unreal) environment.
• In contrast to AR, the user is fully immersed in a simulated digital world.
• A user must wear the VR headset or head mounted display which allows a
360º view of the virtual world.
• This technology can be used to good effect in: medicine (teaching operations
procedures, construction, engineering and the military).
The impact of Virtual Reality (VR) in future on areas
•
•
•
•
•
•
•
•
•
•
•
Military applications (training – operating new tanks or vehicle)
Education (looking inside an ancient building as history lesson)
Healthcare (diagnostic tools to suggest treatment)
Entertainment (gloves, goggles, helmets are worn to fully immerse players and
make it seem very real)
Fashion (to do fashion shows before doing the real thing, checking venue or
cloths)
Heritage (allowing user to walk around and close up to the monuments)
Business (training of different courses to staff)
Engineering (seeing new designs will look in the real environment)
Sport (footballer improving his swinging shoot and getting feedback)
Media (interactive special effects in movies)
Scientific visualization (Cell or a part of a molecular structure)
The End