1. DIGITAL DEVICES
Digital devices are pieces of hardware that use computers or microcontrollers and are found everywhere in
our digital world.
A computer is an electronic machine that can follows a set of instruction to input, process, store and output
data and information that is used in decision making in an organization.
Computer Terminology
The following are commonly used terms in ICT:
Data -These are the basic raw facts that are collected from the field and are meaningless to the user and cannot be
used to make decisions e.g. number of vehicles, amount of items e.t.c
Data Processing (processing) - This is a way in data is manipulated, translated and converted into information. For
example; arithmetic processing (addition, subtraction, etc), logical processing (comparison of two or more numbers),
etc
Information – This is a finished product of data processing that is accurate and summarized in a manner the user can
use to make decision, planning and controlling in business and or in an organization.
Hardware – These are the physical components of the computer. They make up part of the computer that is tangible,
physical and have texture. For example; keyboards, mouse, monitor and system unit.
Software – This is a set of programs and or instructions that instruct a computer to perform a task and how to perform
the task. They give life to hardware for example; hardware can’t be used without software.
Uses of a Computer
Communication – Computer can be used to for communication purpose for example; through e-mail, video
conferencing, messaging applications (twitter, nimbuzz etc)
Education – Computers are used by students to carry out research, do assignment etc
Entertainment – Computers can be used to play games, watch movies, and listen to music etc.
In retail shops – Computers are used in retail shops to manage stock and inventories
In Banks – Computers are used in banking to keep records of deposits and withdrawals
In administration or offices – Computers are used in offices to type letters, memos etc
Manufacturing or industries – Computers are used in manufacturing and processing of products and the production of
goods
Advantages of using Computers
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They are fast - Computers are very fast in processing of data and accessing of information
They are accurate - Computers are very accurate in processing of data. A computer never makes errors but
errors may occur due to wrong data that fed to the computer.
They can store large amount of data - A computer is capable of storing large amounts of data, and can
produce this data again and again on demand. A human being can never do that.
They are tireless - Computers can do millions of calculations with the same speed and accuracy for a long time
without getting tired.
They are can be automated - Once the instructions have been given, a computer can carry on its job
automatically without human intervention until it is complete.
They are versatile - A computer is capable of performing a large number of different jobs depending on the
instructions fed to it and the hardware characteristics of the computer.
They solve complex problems - A computer is able to perform and solve very complex tasks such as complex
calculations that a human being cannot do.
They are safe to use - A computer can be used to perform dangerous tasks or work in environments that can
be harmful to human beings.
They ease up communication - Computers allow people across the globe to communicate with each other, no
matter at what time, via the use of email, video conferencing etc
Disadvantages of using Computers
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They are expensive - computers are very costly to buy and maintain.
Require electricity - computers require electricity to function thus cannot be used where there is no electricity.
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Require Training - they are complex to operate thus one requires training to operate.
They may be health hazards - Use of the computer may lead to health problems such eye strain, backaches
e.t.c.
May lead to unemployment - use of computers may lead to some people losing their jobs.
May lead to anti-social behavior – too much usage of computers lead to lack of social interaction among
people and the society
TYPES OF DIGITAL DEVICES
They range from very powerful Mainframe computers used by large organizations for complex processing tasks such
as statistical analysis and bulk data processing, to Microprocessors used to control washing machines and other
household appliances e.g. personal computers, digital cameras and home entertainment systems.
Features of Mainframe computers are:
1. Powerful - they can process large amounts of data, very quickly
2. Large in size - they are often kept in special, air-conditioned rooms
3. Multi-user - they allow several users (sometimes hundreds) to use the computer at the same time,
connected via remote terminals (screens and keyboards).
4. They are multi-processor – they can have several CPUs thus can carry out many processes at the same
time.
5. Have huge amounts of storage capacity.
6. They have huge internal memory.
Personal Computers – are common in homes and offices and come
in different shapes and sizes such as desktops and laptops. Singleboard computers are affordable computers used in education and
use a microSD card as its storage.
LAPTOPS
Laptops include a keyboard, a screen, a track pad and a rechargeable
battery. Having these features means that they can be taken away
from the desk, which makes them an example of a portable device.
SINGLE-BOARD COMPUTERS
Single-board computers (SBCs) are affordable computers used in
education, embedded computing projects and physical computing
projects. The Raspberry Pi Zero (see Figure 1.6) is an example of
an SBC. The unit itself costs very little and uses a cheap microSD
card as its storage.
Mobile Phones – use a SIM card to connect to a mobile phone
network. SIM stands for subscriber identity module, and a SIM
card is used to identify the subscriber to a mobile phone
network.
Specialist Phones – some mobile phones have
specialist features to provide users with functions
that meet particular use needs e.g an emergency
button for emergency contacts. When the button is
pressed, the phone will call each person on the list
until someone answers.
Smart Phones – Are small computers with Wi-Fi and mobile phone connectivity to make phone calls and access the
internet. They have a more advanced OS than other mobile phones and allows apps to be downloaded onto the
smartphone for users to customize it with entertainment, educational and business features. Most use virtual
keyboards on touch screen to enter text, numbers and other characters. They have shorter battery life because it
combines many features.
Tablets – Bigger than smartphones but have similar features,
i.e. it has touchscreen, apps and Wi-Fi enabled for internet
connectivity. Some have SIM card slots to allow internet
connectivity using the mobile phone network.
Digital Cameras and Camcorders – use light sensors to capture images formed by light passing through the device’s
lens. Image quality depends on the quality of lens, image processor and resolution of the sensor (number of pixels
used by a screen to display and image).
Home Entertainment Systems
Televisions – display still and moving images on a screen. Screen resolution is the number of pixels that are used to
display the image. HD Television screen contain a larger number of pixels.
Most televisions come with built-in speakers but are often small and of limited quality because the screen is usually
very thin.
Most modern televisions can be connected to an external sound system to improve their sound quality.
Smart televisions use apps and can download and stream content from the internet
Sound Systems – Produce loud rich sound using high quality speakers and can be connected to personal devices like
smartphones, media players and tablets using wired connections like USB or wirelessly like Bluetooth. It can also be
connected to a LAN via Wi-Fi to play music stored on connected devices or to the internet to play online music.
Personal Video Recorders – device that records broadcasted content so that it can be watched at a later date. Some
satellite TVs contains both set-top box (STB) and PVR.
Blu-Ray and DVD Players – connect to TVs in order to
play films and other content stored on DVDs. Blu-ray
disks can store HD movies which have high quality
picture and sound.
Game Consoles – Enable users to play video games on a
television screen. They use controllers, Which are often wireless,
to control the characters in the game. Some use motion sensors
to allow the player to control the game with gestures and body
movements. Others use virtual reality controllers and headsets to
immerse the player in a realistic gaming experience, where your
movements in the real world are replicated by an avatar In the
virtual world of the game.
Media Players – provide video and audio content to a
television. Content can be streamed from the internet or from
a network or local storage. Connections can be either wired or
wireless and is controlled using a remote control.
Navigation Aids – (Sat-Nav) can calculate the best route between two or more locations and provide updates to the
route if not followed accurately. Commonly used in cars, delivery vans and ships. They use information from GPS
satellites (Global Positioning System – uses radio signals from satellites to show your exact position on earth), to
determine the exact location of a device on earth. It also uses orientation sensors to know which way the device is
pointing, and the device will display the users position and orientation on a map. GPS do not need internet
connectivity to work but Navigation Aids need internet connectivity to update map data.
Home Automated Devices and Smart Assistants
One type of emerging technology is a group of devices that can be used to create smart homes. For example, home
automation devices can connect a range of digital devices which sense and control functions in the home, such as
temperature and lighting. These functions can be controlled from apps on smartphones or the internet.
Multifunctional and Convergence Devices
Multifunctional devices can perform a range of different functions. E.g. a smartphone, its primary function is to make
phone calls but it can also be used to take photos, function as a navigation aid, music player or handheld game
console.
As such devices develop, they often adopt technologies and features from other types of devices. This is referred to as
convergence. When the designs of a device change so that they become similar to one another). Convergence blurs
the distinction between different types of devices, e.g. smartphones and tablets are similar in that a smartphone has
mobile phone network connectivity and smaller than a tablet. New smartphones are getting bigger to look like tablets
and are called phablets. Tablets can now connect to mobile phone networks.
FEATURES OF DIGITAL DEVICES
 Portability – ability to be carried around easily.
 Performance – The speed at which a device performs is determined by how fast it carries instructions from its
software. Software instructions are carried out by the processor thus a faster processor will increase a device
performance. RAM holds all the software instructions to be carried out by the processor so more RAM will
increase the performance of the device. When space in RAM runs out, secondary storage is used as an
overflow known as virtual memory.
 Storage – More device storage will allow users to store more files and programs.
 User Interface – Users give commands to a device through the user interface e.g. Menu-driven Interface,
Command Line interface, Graphical User Interface, voice and gesture interfaces.
 Connectivity – devices share data by connecting to each using wires or wireless to update software, back up
files or play media from a device.
 Media Support – Different devices can read data from and write data to different types of media.
 Energy Consumption – Digital devices require electricity to work and manufactures are creating devices that
consume less energy to be environmentally friendy.
 Expansion Capabilities – These devices have extra ports like USB slots to allow for connecting to peripheral
devices.
 Security Features –
Software Security – Digital devices have a range of software security
features like Four-digit PINS, pattern PINS and biometric scanners to
prevent unauthorized users.
Physical security – Some devices use security slots which have locks
attached to secure them to furniture.
TYPES OF PERIPHERAL DEVICES
These are devices that can be connected inside or outside a computer or tablet and are grouped into three types: Input
 Output
 Storage
1. INPUT (KEYING DIGITAL DEVICES)
Input peripherals are devices that send data to the computer. They allow the user to control the computer
or store data captured from sources outside the system.
a) KEYBOARDS
Keyboards use buttons known as keys, which users
press to input text or to interact with software.
Keyboards send data to the computer either using
a wired or wireless connection. Different types of
keyboards are used for different operating
systems, languages and functions, as shown in
Figure below.
Combinations of key presses allow the user to
access common software commands called
shortcuts. Some people learn to touch-type,
which is a method of typing without needing to
look at the keys. This increases the speed at
which these people can input data. A shortcut a
combination of key presses used to access
common software commands quickly.
b) Numeric Keypad/PIN Pad
This is a small input device that looks like a keyboard but only has numbers. It is used to
enter numeric data into computers for example, those in ATMs, lifts etc. Most computer
keyboards have a numeric keypad on the right side, and most mobile phones (there are
also computers) have a one for entering phone numbers, etc. PIN pads are mostly found
on electronic door locks – you enter a PIN to unlock the door.
2. POINTING DEVICES
A pointer is used on a screen to select displayed objects. There are several types of device that allow you to
control a pointer.
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Mouse: A mouse uses an optical sensor to recognize the
movement of the device. Its sensitivity can be affected by
the surface upon which it is placed. Some mice use roller
balls to control the movement of the pointer.
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Tracker ball: A tracker ball is rolled to move the pointer. It
does not have buttons to press.
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Track pad: The track pad surface senses finger
movements, touches and presses.
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Joystick: Joysticks are commonly used on games controllers
to move sprites around the game
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Graphics tablet: A graphics tablet is a flat pad that is used with
a stylus. Users use the stylus to draw or write on the graphics
tablet. These devices are often used by digital artists and
designers.
3. SCANNER (INCLUDING OCR AND OMR)
Scanners use light sensors to record physical documents as images, which are then saved as files to the
computer. Software allows scanners to read characters on the document and store the result in a text file.
This is known as Optical Character Recognition (OCR).
Optical Mark Recognition (OMR) software can also be used with scanners to detect simple marks on a
document. A common use for OMR is for recognizing and recording responses to multiple choice tests.
4. BARCODE SCANNER (OBR)
A barcode is a pattern of lines and gaps that can be read by barcode scanners, which detect the width of
lines and gaps in a barcode. Barcodes are often used on parcels, so that they can be tracked, and on items
for sale in shops. The barcode represents letters and numbers which are used to identify the item.
There are two types of barcode:
• Linear
• Matrix
Matrix codes are also known as OR codes. They are newer than linear barcodes and have some advantages
over linear barcodes, such as:
• They can hold much more information than linear barcodes
• They can be scanned from any angle
5. WEBCAM
Webcams are specialized cameras. They are generally lower quality than camcorders, and may have built-in
microphones to capture sound. They can be used as security cameras and can stream images or video to the
internet.
6. MICROPHONE
A microphone is used to capture sound. It uses a
diaphragm which moves when air hits it. This
movement produces an analogue electrical signal. A
microphone converts the electrical signal to a
digital signal with its sound card, which acts as an
analogue-to-digital converter.
Small, low-quality microphones are often built into
computers and are used for voice recognition,
recording speech or allowing VolP calls using
software such as Skype©. Higher quality
microphones are often used by recording artists and can be connected to a sound card's audio input port.
7. TOUCH SCREEN
Touch screens are used in many devices, including smartphones, tablet devices, laptops and desktop
computers. There are two types of touch screen:
• Resistive
• Capacitive.
RESISTIVE
When a user presses on a resistive screen, the pressure causes two layers
underneath the screen to touch and make a connection. Resistive touch
screens are more durable than capacitive touch screens, but are harder to
read because more layers reflect more light. In addition, they can only
recognize one touch at a time, so they are not suitable for multi-touch
applications.
CAPACITIVE
Under the glass of a capacitive screen, there is a layer of capacitive
material. When a user touches the screen, a small amount of charge flows
away from their finger because humans are conductive. The change in
electrical charge is measured precisely: the closer the finger is to the
charged areas, the more current flows away. This allows the computer to
calculate the precise location at which the screen was touched. Capacitive
touch screens are often used in smartphones.
8. BIOMETRIC SCANNER
If you have watched a spy film, you may have seen a biometric scanner being used. Biometric scanners work
by measuring part of the unique physical characteristics of a user, often multiple times, until a suitable
average result is produced. This average result is then stored and future samples are compared against it in
order to check whether the person being scanned is the
authorized user. This allows the information to be updated so that the saved sample is perfected.
Four examples of biometric scanners are as follows: Fingerprint recognition: These
scanners read the patterns of arches,
loops and whorls in a human
fingerprint. Fingerprints are unique to
each individual person, which makes
them a useful method of identification,
but fingerprints can be obscured,
damaged or changed, such as by injury
or disease.
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Facial recognition: These scanners identify the structure
of a human face in order to identify an individual
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Voice recognition: These scanners require a microphone to
capture the voice. They then compare the voice print
against a saved original and check to see whether the two
prints match.
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Iris recognition: Like fingerprints, the human iris
has a unique pattern, though an iris scan is
approximately 120 times more detailed than a
fingerprint. This means that iris recognition is
120 times more reliable when identifying
people.
9. CARD READERS
Card readers are used to read data stored on a card that is carried by a user. The data can be used to unlock
doors, access secure areas, make payments or track people, parcels and even pet animals. Cards can carry
data using three methods. Each method needs a specialist
type of reader.
Magnetic strip: This is the least secure method as the data on the magnetic strip can easily be stolen by
criminals who put the card through a card reader without the card owner's knowledge.
Programmable chip: Data on a programmable
chip is only readable when a correct PIN is
entered into the reader. In 2005, the UK
introduced the chip and PIN system, which
reduced certain types of fraud by 67%.
Radio Frequency Identification (RFID) and
Near Field Communication (NFC): RFIO is a
short-range wireless communication method,
and Near Field Communication (NFC) is a
branch of RFIO.
RFIO tags are cheap and small and they can be
included in a variety of objects such as cards,
key fobs and smartphones. They contain a
unique identification number (10) that is linked
to records in a database
10. SENSORS
This is an input device that captures or detects physical quantities about the environment (such as
Temperature, light intensity, humidity, and pressure) and feeds it into the computer.
For the computer to understand a Sensor it needs an ADC (Analogue-To –Digital Converter)
This is a device that converts the Analog signals sensed by the sensor from the environment into a Digital
signal that a computer understands.
Sensor
ADC
Computer
Sensors are one of the main features of smart devices such as smartphones and smart environments such as
smart homes.
NB:
Sensor is an input peripheral that inputs data about the physical environment
Smart home a home equipped with devices that can connect to the internet and be controlled remotely by a
computer or smartphone app.
Type of Sensor
1 Temperature
sensors
Applications (Used in:)
Automatic washing machines, central heating systems, automatic temp
control in greenhouses, ovens, Microwaves
2 Pressure sensors
Burglar alarm systems, washing machines, robotics, environmental
monitoring, monitor and control traffic lights, axle weights for vehicles.
3 Light sensors
Automatic greenhouses, automatic doors, burglar alarm systems,
controlling street lights.
4 Sound sensors
Burglar alarm systems, monitoring liquid and powder flow in pipes
5 Humidity/Moisture Automatic greenhouses, environmental monitoring, factories where
sensors
moisture levels are crucial(e.g. manufacture of microchips, paint spraying)
6 pH sensors
Used to measure and control the PH (Acidity and alkalinity) of substances in
Automatic greenhouses, chemical processing plants, environmental
monitoring places.
Advantages of Sensors
 Data captured or detected using sensors are generally more accurate than those taken by human
being.
 They can record data continuously and reliably unlike using people who are unreliable and will make
errors.
 They can detect or capture data that people do not sense accurately i.e. humidity
 The system can be automatic, removing the need for human to be there all the time.
 The Data captured can be automatically recorded in a form that can be processed by a computer i.e.
saved in Ms Excel
 Can work in dangerous environment that might be too dangerous for human health i.e. in volcanoes.
Disadvantages of Sensors
 Faulty sensors can give wrong results (e.g. if the sensors on the rear bumper of a car which monitor
for obstacles become dirty, they may either not identify an obstacle or give a wrong alarm.
 Sensors cannot interpret data
 Sensors cannot detect everything else in the environment except what they are configured to.
 They can’t make decisions.
2. OUTPUT PERIPHERAL DEVICES
Output peripherals are connected to a computer and output the results of the computer's processing in
various forms, including:
• Electronic display
• Printed text
• Video
• Audio
• Tactile (touch) forms
1. MONITORS
These are visual display output devices that display
information from the computer in softcopy (electronic
display).
Features of monitors include:
• Screen size, which is measured diagonally
• Resolution, which is measured in pixels
• Energy efficiency measures, such as going into a low-power
standby mode if no input is detected.
Some monitors also use touch screen technology
There are two types of monitors;
 Cathode Ray Tube - CRT
 Thin Film Transistor – TFT
CRT (Cathode Ray Tube) Monitor
This is a type of monitor that uses an electron gun to fire electrons against a phosphor screen, which creates
a picture that is made up of tiny dots.
TFT (Thin Film Transistor) monitor
This is a type of monitor made up of thousands of tiny dots (pixels), which are made up of transistors
controlled by a micro-processor. They are commonly found in laptops, iPads and other portable devices.
Uses of Monitors
1. Used as the primary output device for computers so that the user can see immediately what they are
typing in.
2. Monitors also display the programs so that the user can choose what to do by clicking.
3. Those with touch capabilities can be used as input device to issue commands.
COMPARISON BETWEEN CRT AND TFT MONITORS
CRT
TFT
SIZE
WEIGHT
DESK SPACE
ENERGY CONSUMPTION
Large in size
Heavy
Occupy more desk space
Consume a lot of electricity
COST
SCREEN FLICKERING
HEAT
Less Costly than TFT
Flickers a lot
Produce a lot of heat
NOISE
Produce a lot of noise
Small in size
Light in weight
Occupy less desk space
Does not Consume a lot of
electricity
More costly than CRT
Does not Flicker
Does not Produce a lot of
heat
Does not Produce a lot of
noise
2. PRINTERS
There are three types of standard printer: dot matrix, inkjet and laser
 Dot matrix: These printers are sometimes called 'impact' printers. This is because the print is made
by hitting or 'impacting' the paper through a ribbon of ink, and this process is very noisy. The paper
often has a number of carbon copy layers so it can make several copies of the same document as it
prints it
 Inkjet printers: These printers use cartridges containing different coloured ink. Black ink is held in a
one cartridge, while the colour cartridge is often split into three colours: cyan, magenta and yellow.
Tiny dots of these inks are sprayed onto the paper to form images or text
 Laser printers: These printers contain a rotating cylinder or drum that holds an electrical charge. A
laser is used to discharge certain points on the drum and 'draw' an image. Electrically charged toner
is attracted to those points on the drum and is heated onto paper that is passed over the drum.
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3D PRINTER
Three-dimensional (3D) printers create real-life
versions of digital models. These printers work by
adding layers of heated material from the bottom of
the model all the way to the top. 3D-printed models
take a long time to create.
3D printers are often used to create complex items,
sometimes with working parts. Some of these items could not
be assembled in any other way. Examples of 3D-printed items
include aeroplane parts, artificial limbs, prototype models of
cars and even food such as pasta and chocolate.
3. PLOTTERS
Plotters are used by a variety of professionals, including
product designers, architects, Engineers and cartographers. The
plotter draws high-quality images created in Computer Aided
Design (CAD) software onto large sheets of paper. It does this
by moving a pen across the paper to draw the lines, and the
pen can be raised away from and lowered onto the sheet of
paper. Some plotters can also roll the paper backwards and forwards.
4. DATA PROJECTORS
Data projectors are used for home entertainment, such as
watching television or playing games, and for giving
presentations in classrooms and business meetings. They
have the following features.
 Light bulbs: These bulbs can have various brightness
levels (measured in lumens) and are expensive to
replace.
 Resolution: Like monitors, they use different quality
screens
 Zoom functionality: The projected image can be made larger by enlarging the image using either
optical zoom or digital zoom.
 Portability: Some smaller and lighter projectors are available, and these are easier to move around.
5. SPEAKERS
Speakers allow a computer to output sound. Speakers often
come in pairs to provide stereo sound. Multiple speakers are
commonly used to provide surround sound in home
entertainment systems. These speakers need a special
amplifier that can deliver different levels of sound to each
speaker to provide spatial awareness.
Stereo sound - sound that comes from two sides (left and
right)
Surround sound - sound that comes from four or more sides,
used so that sounds from a film or television program come
from all around the viewer as they would in real life
6. CONTROL DEVICE
Control devices are also known as actuators, and they are components of a system that make something
happen in the real physical world. These devices are often mechanical. Examples of actuators include:
• Valves
• Pistons
• Heaters
• Coolers
• Motors
3. SECONDARY STORAGE
Secondary storage is often referred to as 'storage'. However, it should not be confused with primary storage
or main memory, sometimes referred to as Random Access Memory (RAM) or Read Only Memory (ROM).
Secondary storage is non-volatile, which means it will not lose data when the system's power is turned off.
Secondary storage is used for:
• Storing a document for future use
• Storing an application, ready to be loaded into RAM when the user opens the application
• Virtual memory - space on a computer for storing instructions and programs until they are needed or
being used.
Motherboard is the circuit in a computer with connectors to which other components connect
SECONDARY STORAGE DEVICES
Secondary storage devices are used to store data or software that is used in a computer system. Storage
devices can be either internal or external.
Internal drives connect directly to the computer's motherboard. External devices are connected to the
computer's motherboard through the different ports and adapters on the computer's exterior
There are different types of secondary storage devices: Hard Disk Drives (HDD) contain hard disk media. The drives provide a connection from the disk to
the motherboard, either directly or using a wireless adapter like Wi-Fi or a wired port like USB.
 Solid State Drives (SSD, often referred to as flash drives) contain flash memory media. They are
otherwise identical to hard disk drives.
 Optical Disk Drives contain optical disk media. Newer drives are often compatible with older media.
For example, a disk drive that can read Blu-ray media can also read DVD and CD media. This is known
as backwards compatibility.
Other:
 Online / Cloud storage – data storage over the internet i.e on hosted servers on the cloud.
1. A storage medium is the actual material object used for storing the data.
2. A storage device is the item of equipment that handles the use of the medium. E.g. a DVD is the
storage medium while the DVD drive is the device that is used to access data on the DVD.
3. Backwards Compatibility - the ability to be used with older technology without having to be specially
adapted.
Comparison Between SSD and HDD
Stands for
Speed
Heat, Electricity,
Noise
Defragmentation
Components
Weight
Dealing with
vibration
HDD
SSD
Hard Disk Drive
HDD has higher latency, longer read/write
times, and supports fewer IOPs (input
output operations per second) compared to
SSD.
Hard disk drives use more electricity to
rotate the platters, generating heat and
noise.
The performance of HDD drives worsens
due to fragmentation; therefore, they need
to be periodically defragmented.
HDD contains moving parts - a motordriven spindle that holds one or more flat
circular disks (called platters) coated with a
thin layer of magnetic material. Read-andwrite heads are positioned on top of the
disks; all this is encased in a metal cas
Solid State Drive
SSD has lower latency, faster
read/writes, and supports more IOPs
(input output operations per second)
compared to HDD.
Since no such rotation is needed in
solid state drives, they use less power
and do not generate heat or noise.
SSD drive performance is not impacted
by fragmentation. So defragmentation
is not necessary.
SSD has no moving parts; it is
essentially a memory chip. It is
interconnected, integrated circuits (ICs)
with an interface connector. There are
three basic components - controller,
cache and capacitor.
SSD drives are lighter than HDD drives
because they do not have the rotating
disks, spindle and motor.
SSD drives can withstand vibration up
to 2000Hz, which is much more than
HDD.
HDDs are heavier than SSD drives.
The moving parts of HDDs make them
susceptible to crashes and damage due to
vibration.
MEDIA
A. Hard disks
Hard disks are made up of many concentric platters. These platters make up a cylinder that spins on a
central spindle. A read/write head moves on an arm across tracks on the platter.
The amount of time that it takes the read/ write head to access data on the tracks is determined by how fast
the cylinder of platters spins and how fast the read/write head is moved across the tracks.
When reading, a read/write head changes the magnetic field into electrical current. When writing, it
transforms electrical current into a magnetic field.
Typical spin speeds are 5400 revolutions per minute (rpm) or 7200 rpm.
The average seek time for a read/write head is 4-15 milliseconds (ms).
Storing data on a storage device is also called WRITING while retrieving data from a storage device is also
called READING.
PARTS OF THE HARD DISK
1) Spindle – Holds the platters in place and
rotates them so that the Read/Write Heads can read
or write information on the platters.
2) Read/Write Heads – Use principles of
magnetism to write or read information on the
platters.
3) Platters – Circular metallic or glass discs
coated with magnetic material to store data.
4) Actuator – Controls movement of the
Read/Write Heads.
B. Optical media
Types of optical media include CDs, DVDs and Blu-ray
disks.
 CDs can store up to 700 MB of data. The data
is written to the disk using a laser, which writes data
to a plastic layer beneath layers of aluminium and
acrylic.
 DVDs look very much like CDs. Data is written
to DVDs using a shorter wavelength of red laser light, which allows DVDs to store more data. They
can store 4.7 GB on a single-sided, single-layer disk. Double-sided, dual-layer disks can store as much
as 18 GB.
 Blu-ray disks are similar to CDs and DVDs, but use a scratch-protection coating. Violet laser light is
used to store data at greater density than the red laser light used in DVDs. They can store 25 GB on a
single-sided disk, and double-sided disks can store 50 GB.
All optical media is recordable and is known as CD-R, DVD-R or BD-R. Some CDs and DVDs can be rewritten
(CD-RW, DVD-RW), and some Blu-ray media can be written then erased and rewritten (BD-RE).
C. Flash media
Flash media are more energy-efficient than hard disks as they do not have moving parts. For the same
reason, they are also less likely to fail when they are moved around. This makes them suitable for use in
portable devices.
D. Magnetic Tapes
Magnetic tape is a large capacity, serial access medium. Because it is a serial access medium, accessing
individual files on a tape is slow. Tapes are used where large amounts of data need to be stored, but where
quick access to individual files is not required. A typical use is for data back-up (lots of data, but rarely only
accessed in an emergency). Tapes are also used and in some batch-processing applications (e.g. to hold the
list of data that will be processed).
The storage capacity of a storage device is measured in bytes, Kilobytes (KB), Megabytes (MB), Gigabytes
(GB), and Terabytes (TB). The computer requires one byte of storage space to store one character of data. A
character is anything that can be stored in the computer e.g. a letter, a number, a space, a full stop, etc. (A,
9, +, ?, @).
Each character is made up of eight bits. The word BIT is a short form of BInary digiT. Binary digits are either
a “0” or a “1”. All data stored in the computer is stored as a series of binary digits (Bits) i.e. a series of 1s and
0s. e.g. letter A is written as 01000001.
Storage media store data in binary form. This means that each bit of data holds one of two values: 0 or 1.
Different media types interpret 0 or 1 differently.
 Hard disks change the magnetic charge of a platter to either negative or positive, depending on
whether the value is 0 or 1.
 Optical media use tiny bumps on the disk's surface to represent 0 and 1.
 Flash media use different levels of electrical charge, held in tiny individual cells, to represent 0 or 1.
 Magnetic tape changes the magnetic charge of the tape to either negative or positive, depending on
whether the value is 0 or 1.
Software
 Digital devices consist of physical components referred to as hardware. The hardware devices of a digital
device can not function without software.
 Software is a set of instructions tell the digital devices what to do and how to do it.
 Software can also be referred to as programs or software programs.
 Software is classified into two:1) Systems Software
2) Application Software.
Systems Software
 This are sets of instructions that control the general running of the digital device.
 They are designed to operate ,maintain and control the computer hardware and provide a platform for
running application software
 There are two categories of system software;
1) Operating systems
2) Utility programs
Operating System
 An Operating System (OS) is a software that allows a user to use, control and manage the hardware of a digital
device. It also provides a platform to run other system software and application software.
 It is the most important software on any device, without which, the device won’t function.
Examples of Operating Systems;
 Windows Operating System – Windows 10, 8.1,8,7,xp,98
 Android
 Linux
 iOS
 Unix
The diagram shows how an operating system lets a user control the Hardware directly or by using application software
and other system software.
Types of Operating Systems
 Operating Systems can be categorized based on how they function as follows;
1) Single-user OS – can only allow one person to use at a time.
2) Multi-user OS – can allow more than one person to use at a time.
3) Single-tasking OS – can allow a user to perform only one task at a time
4) Multi-tasking OS – can allow a user to perform multiple tasks at a time.
5) Network OS – have additional functionality, including; Sending requests to a server when users log in with
their username and password, Separating user accounts and ensuring that users cannot access each other's
files, Providing access to network storage and shared resources such as networked printers.
Functions of the Operating System
1) Provides a user interface – the OS provides a way through which we can interact with the computer e.g. when
we click an icon to open a program.
2) Controls application software - It manages applications that are running on the computer, starting or stopping
them when the user requests.
3) File management - It manages files, helping us save our work, organize our files, find files that we have saved
and load files.
4) Resource Management - It manages systems resources like the memory and CPU i.e. Allocating memory
(RAM), space to programs and Keeping track of which parts of the memory (RAM) are used and free.
5) Error handling - It deals with any errors that occur when a program is running or when data is been transferred
somewhere.
6) Print Spooling - Manages the printer spool allowing different tasks to be printed on the same printer one at a
time.
7) Input and output management - It manages the computer’s input and output hardware such as printers, which
involves; Accepting data from an input device and transferring it to the memory (RAM) and making sure that
any output is sent to the correct output device.
8) Manages the system security which involves - Monitoring and restricting access to the systems, programs and
data. and Preventing malicious files or users who is far away from damaging your system i.e. a virus or a
hacker.
Security Features provided by OS
The OS manages the security of a device by providing the following features;
a) Firewalls - Preventing malicious files or people from damaging your system.
b) User account and password management
c) File and disk encryptions
d) Setting file permissions(e.g. read & write, write only, read only)
e) File access/File sharing settings(sharing a file with only particular users )
Utility Programs
This are software programs that carry out configuration and maintenance tasks in a digital device
They include:
a) Backup utility programs
b) Defragmentation utility programs
c) Compression utility programs
d) Disk Formatting utility programs
e) Disk cleaning utility programs
f) Disk checkers/scanners
 Backup Utilities create an extra copy of files and programs. Backups can be set to run automatically (usually at
a time when the system is not in use) or can be started by a user.
 Defragmentation - As data is stored to hard disk, It is spread across the disk wherever there is free space. This
means that sometimes data is fragmented and stored out of order or out of sequence. Data from the same file
may be spread over multiple locations on a platter, on different platters in the cylinder or sometimes even on
different disks.
When these files are loaded, data has to be retrieved from these multiple locations. The read/write head of the hard
drive has to find this data, which takes extra time and slows down the process of loading the files.
To avoid this and to speed up the system, disk defragmentation utilities reorder the fragments of data so that they
are stored as close to each other as possible. Defragmentation utilities are usually set to run automatically, but they
can also be started by a user.
COMPRESSION UTILITY
• Compression utilities reduce the original size of a file or set of files thus reducing space occupied by the file on
the disk. Where there are repeated patterns of data, rather than storing every repeated instance, only the first
instance of the data is stored, alongside how many times it is repeated.
• For example, in the figure below, there were eight instances of a, 6 instances of b and 2 instances of c in the
original file. This data can be compressed to be stored as 'a8b6c2', which reduces the amount of storage
needed.
• The resulting compressed file is not usually readable by the original application. Compression utilities also
have the ability to decompress (extract) the data from a compressed file so it can be read by the original
application again.
Disk Formatting - Disk formatting prepares storage media such as a hard disk drive or USB flash drive for its first use.
If a disk has already been used, then formatting it will make all of the data on the disk unreadable by normal
applications. Disk formatting utilities make this process easy for users by providing them with the option to choose the
file system, file unit sizes and the name of the
disk. Perhaps most importantly, they make sure that the user really wants to format the disk.
Different operating systems require disks to be formatted in certain ways in order to perform specialist tasks. Disks
can also be formatted in a way that makes them compatible with all operating systems.
Formatting a disk will not erase the data completely and it can still be recovered using specialist tools, but there are
some utilities which will overwrite the data so that files cannot be recovered
OTHER Functions of Utility Programs
 File compression i.e. pressing a file so that it occupies as little space as possible.
 File sorting i.e. arranging files in alphabetical order so that they are easy to locate.
 File renaming i.e. changing the name of a file.
 File conversion e.g. convert a sound file to MP3 or MP4.
 File repair i.e. recover data from a damaged file.
 Storage device defragmentation (defragging) i.e. arranging files together to create space for other files.
 Storage device repair i.e. checking your storage device for faults and then repairing them or giving you a
warning that your storage device is about to crash.
 Formatting Storage Devices i.e. removing all files in case they are damaged, infected with a virus or you want
to use the device on a new OS i.e. moving from Windows to Mac OS.
 Provides drivers that will ensure that the computer communicates with the hardware attached to it.
Application Software
This are programs that allow users carry out specific tasks.
They are also referred to as Application Software or simply apps.
Apps are usually installed from a disk or downloaded from servers on the internet. Some devices, like smart phones
and tablets, use operating systems that provide access to app stores. Some of these only make apps available to users
after the store has checked the quality of the app and has ensured that the app does not include code that will harm a
user's device or data. Apps can also be installed from storage media like DVDs.
By use of application software, users produce a digital product, such as a document, presentation or image.
Categories of Application Software
1) Word processors
2) Spreadsheets
3) Database Management Systems
4) Presentation Software
5) Desktop Publishers (DTP)
6) Graphics software
7) Web authoring Software
8) Web Browsers
9) Communication Software
10) Audio & video Editing software
11) Project Management Software
12) Educational Software
13) Control Software
Office Productivity Software
Office productivity software refers to a set of application software that can carry out work-related tasks. They are
commonly used in offices to enhance productivity in office work.
They are often available as an application suite, e.g. the office suite which comprises of MS Word, MS Excel,
PowerPoint, MS Access, etc
Application suite:- A collection of application softwares that share the same look and user interface and often come
bundled together.
Office productivity software includes a number of types of application software such as; Word processors,
Spreadsheets, Database management systems (DBMS), presentations software, etc.
Word Processors
• Word Processors are software that enables users to create, format, edit or manipulate text documents.
• Most documents consists of text but may also contain some images, tables, hyperlinks, equations, simple
drawings and shapes and charts.
• Word processors are used in creating documents such as Letters, Reports, Essays, Books etc.
• Examples of word processors include;
• MS Word, Writer, Word Perfect, Word star, etc.
Features of Word Processors
1) They usually come with spelling and grammar check tools that identify errors in as the user types.
2) Allow users to change the font and provide different layout views to allow users to position text and images on
the page.
3) Some word processing applications allow people to work together on a document. Comments can be added to
the text so that others can understand the writer's intention and give feedback.
4) The software can also track any changes made to the document, giving others the option to accept or reject
those changes.
Spreadsheets
This is a program which displays information in form of a table divided into rows and columns forming individual boxes
known as cells. Spreadsheet programs allow calculations to be done on cells or on group of cells.
Examples:- MS Excel, Lotus 1-2-3, Quadra Pro, Open Office Spreadsheet
Features of Spreadsheets
1) Has a feature that allows users to enter text, number or formula into any cells
2) Have features to display data in charts.
3) Has formula that allows calculations to be done on other cells.
4) Allows a variety of operations to be done on rows and columns e.g. resizing rows and columns, inserting and
deleting rows and columns.
Database Management Systems (DBMS)
Database management systems are programs that enable users to create and manage databases. Some systems can
also produce reports that dynamically display real-time changes to the data as it updates.
Examples; MS Access , Oracle, MySQL, FoxPro, Open Office Database, D Base II plus
Features of DBMS;
1) Data entry forms so that users can input data
2) Query editors so that users can select all data that meets certain criteria
3) Report builders so that users can display data in a more readable format.
4) They store data in form of record. A record is a collection of related fields.
5) Has ability to sort data into different orders.
6) Has the facility to combine results from tables into reports.
Image Editing Software
These are application software that enable us to create and edit images.
Image editing applications can be categorized into two;
a) Drawing software – they are used to create vector format images. This are images made through a sequence
of commands or mathematical statements that place lines and shapes in a given two-dimensional or threedimensional space. E.g. Adobe Photoshop
b) Painting software – they are used create bit-mapped images. These are images produced by changing the
colors of the dots that make up the image (pixels). E.g. Paint
A) Drawing Packages (Graphics Editors)
They allow us to create or edit vector graphics.
An example of drawing software is Adobe Photoshop.
Features of graphics editors include:
• They are able to vectorize images – i.e. to convert bitmap images to vector image
• They allow use of layers - the ability to place some graphics on top of others
• Adding text
• Adding or drawing shapes and lines
• Resizing, aligning or moving shapes and lines
• Altering the color of shapes, lines and fill areas.
B) Painting Packages (Photo Editors )
These allow users to edit and enhance digital photographs and images.
An example of photo editing software is Paint.
Features of photo editors include;
• Adjusting brightness and contrast
•
Resizing the image
•
Altering sharpness and blurring
•
Applying filters and effects such as distortion
•
Red-eye removal
•
Cropping
Difference Between Vector & Bit Mapped File Images
Graphics can be categorized into two; Bit-mapped file images and vector-format files. The table below shows the
difference between these two.
BIT MAPPED FILES
VECTOR FORMAT FILES
Produced by painting packages
Is produced by drawing packages
Quality of the image is lowered when the image
is resized
Quality of the image isn’t affected when image is resized
Take up a lot of memory space compared to
vector format files
Take up little memory space compared to bit mapped file
format
Produced by changing the color of pixels
Are represented by mathematical codes.
Desktop Publishers (DTP)
• These are software that are used to create publications such as magazines, newsletters, leaflets, posters etc.
• They very similar to word processors but are more suitable for creating publications that require a mixture of
graphics and text.
• Examples of DTP include; MS Publisher, Adobe Illustrator, Adobe InDesign, Corel Draw, Page Maker, etc.
Features of DTP;
• They allow blending of images and text.
• They have text place holders that allow one to precisely place text in the page
• They require some expertise to use unlike word processors
Sound Editors
Sound editing software allows users to edit audio files or to join together different audio files in order to create
multitrack music or soundtracks for video.
An example of sound editing software is Audacity®.
Features of this software include;
• Cut and join audio clips
• Mute and solo some audio tracks
• Alter volume levels for individual tracks
• Change tempo
• Frequency equalization (changing the levels of high and low pitch frequencies)
• Add effects like reverberation
•
Apply audio processing such as Reverse, Noise reduction, Normalization, Fade the volume in, so that it gets
louder, or out, so that it gets quieter.
Presentation software
Presentation software allows users to create multimedia content, including images, text, animation, audio and video.
This content can be placed on slides or pathways that are used to illustrate and support the spoken content of a talk
given to an audience.
An example of presentation software include MS Power Point and Prezi.
Features of a Presentation Software;
 Some applications allow users to practice timings and add narration that automatically plays back on the
appropriate slides.
 These slides can be set to advance(move) automatically after a set period of time, or on command from the
presenter.
 Notes can be added to the presentation to remind and prompt the presenter to speak about specific points
during the presentation.
Web Authoring Software
These are software that enable users to create web pages. Web pages are hypertext documents containing include
text and images created using Hypertext Markup Language (HTML). They can only be opened using a web browser
software such as Google Chrome, Microsoft Edge or Mozilla Firefox, etc.
Web browsers translate HTML tags into pages that people can see and read. Web pages can be linked together to
create a website for people to view on the internet.
Although some people prefer to create or customize web pages by writing their own HTML, some web authoring
applications will allow users to produce complex websites with little or no experience of HTML coding.
These applications are sometimes called 'What You See Is What You Get' WYSIWYG) editors, because the published
page will look very similar to the page that the user edits in the web authoring application.
An example of web authoring software is Adobe Dreamweaver, MS Web Expression, MS Front Page.
Web Browsers
Web browsers allow users to view web pages and websites created in web authoring software.
Web pages could be locally on the computer or hosted on web servers that could be accessed through the internet.
These servers may be in another country. Different browsers have different features and compatibility with file types
used on the World Wide Web.
Browsers also allow users to access other systems that use the internet but are not on the World Wide Web, such as
file transfer protocol (FTP) servers, e-mail, instant messaging, etc.
Examples of web browsers include Google Chrome, Microsoft Edge or Mozilla Firefox, etc.
Control Software
Control software are used to automate the movement of control devices or actuators, such as motors. They make
something happen in the physical environment.
Control software takes input from sensors, makes a decision based on the input value and then outputs something,
such as a command, as a result.
Control software is often used in engineering, vehicles and building control systems. However, a developing group of
control applications is in the area of home automation systems, where devices can be monitored and controlled using
a smartphone app.
Applications of control Software;
Application software are commonly used in control devices such as;
 In lifts
 Traffic lights
 Burglar Alarm systems etc.
Project Management Software
A project is a lengthy task that needs to be completed within given time and budget.
Project management applications are used to help plan and track the individual tasks in a project, so that project
managers can make the most efficient use of the available resources.
Some tasks cannot be started until a previous task is completed or has been partly completed,
It is important for a project manager to see which tasks are dependent on others. When all of these dependent tasks
are combined together into a timeline, it is easy for the project manager to see the critical path.
Features of Project Management Software;
 It can set milestones – important steps in the project.
 Has a feature that allocates tasks to individual people or groups of people.
 provide tools for tracking the costs
 Able to arrange for resources to be delivered on time.
Communication Software
These are application software that enable us to communicate through electronic networks or smartphones. Common
examples include;
 E-mail applications such MS Outlook, Gmail App on smart phones.
 Social Media applications such Facebook, Instagram, etc.
 Short messaging Service (SMS) applications found on mobile phones. They enable a user compose a message
of up to 160 characters using the mobile phone network and do not require an internet connection.
 Multimedia Messaging Service (MMS) applications that extend the capabilities of SMS. Can deliver more than
160 characters per message and can include video, animations, images and audio. Like SMS, they are sent
using the mobile network and do not require Internet connection
 Instant Messaging Apps such as WhatsApp – they are very similar to MMS applications, but they require a
connection to the internet. They can allow users to see when other users are typing, and users can also
prevent others from seeing when they are typing.
Software Licensing
A software license is a legal document governing the use or redistribution of the software. It give a user permission to
use one or more copies of software in ways where such a use would otherwise potentially constitute copyright
infringement of the software owner's exclusive rights under copyright law.
When buying software, the purchaser may acquire some or all of the following: Copy of software on a CD-ROM or access rights to download software from website.
 Manual explaining how to use the software.
 A license to use the software.
Sometimes, users require a software license to be able to install and use software on a computer.
Types of Software Licenses
1) Proprietary
2) Open Source
3) Trial Version
4) Shareware
5) Freeware
There are a variety of different types of software licenses, with different characteristics and conditions:
1) Proprietary - Proprietary software, or closed source software, is computer software licensed by the copyright
holder with the intent that the licensee (the user) is given the right to use the software under certain
conditions, and restricted from other uses, such as modification and sharing.
2) Open Source - This type of license makes the source code and design of the software available to anyone who
wants to enhance or develop it. It is important not to confuse open source software with free software.
3) Trial Version - Trial version refers to a version of the software that is only usable for a certain period of time
before it has to be purchased.
4) Shareware - This is where software is initially made available free of charge to users. Software functionality
may be limited, with additional features becoming available only after payment.
5) Freeware - This is software which can be copied or downloaded for free. It is often fully functional. Examples
may include software developed by organisations such as universities, where the aim was not to profit from
the software. Freeware and shareware should not be confused.
Software Updates
Software updates refer to newer versions of the software which may be installed in part or an overhaul. An update
is simply a change or addition to a computer file so that it has the most recent information.
Software updates are usually made available for download from a server on the internet. Some updates can be
scheduled to happen automatically when they are released. It is important to back up a system and files before
updating software in case the update introduces problems, such as removing components that other software needs
in order to function.
Reasoning for Updating Software
1) Fixing security vulnerabilities or bugs in the software
2) Increasing compatibility with newer operating systems and devices
3) Improving performance and efficiency
4) Introducing new features
5) Improving usability i.e. make it easy to use the software or device.
NB:
 Bugs are errors in the program's source code of a software program.
 Compatibility is the ability of the software to work with other devices, systems and applications.
Memory
Memory refers to devices that hold data while is being processed. Memory is used during processing because it has
a higher access speed, i.e. can be accessed faster than secondary storage.
Memory is used to store instructions so that the processor can fetch them quickly in order to process them. It is
often called main memory or primary storage. The normal storage of a device is often called secondary storage.
Types of Memory
There are three types of memory that you need to know about:
1) Random Access Memory (RAM)
2) Read Only Memory (ROM)
3) Flash memory
1) Random Access Memory (RAM)
2) RAM is a hardware device on the computer in which Software instructions are loaded from the computer's
secondary storage (hard disk).
3) The processor then fetches the instructions from RAM and executes them.
4) RAM is volatile, i.e. it looses data when power is turned off. This means that, if you turn off your computer, any
data held in RAM will be lost.
5) It is also a temporary storage device meaning, the contents can be altered or removed and others put.
6) RAM is used to hold the programs that are running on the computer. The more RAM available, the more
programs can run at the same time. This is important when you need to use many files or programs at the same
time.
7) RAM can be upgraded, a user can buy and add more RAM to a system. This can improve the performance of a
computer system when the user is using multiple files or programs at the same time.
Impact of the Size of RAM on User Experience
When the computer does not have enough space in RAM, the operating system is forced to create virtual
memory by using a section of the hard disk.
Accessing data on the hard disk is much slower than RAM, so the user will notice a big decrease in system
performance shown by the computer being slow or hanging.
When there is more RAM on the computer, more programs and data can be loaded at once thus enabling the
computer to process data faster.
When a solid state drive (SSD) is used instead of a hard disk, data is swapped to and from the SSD more quickly
and frequently.
However, although SSDs have faster access times than hard disk drives, this constant swapping can still greatly
reduce the performance of the SSD.
3) - Read Only Memory (ROM)
4) ROM stores data permanently. It is non-volatile, i.e. its contents are not lost when the power is turned off or
when the computer is switched off.
5) ROM is used in devices that store only one programme. These are referred to as single purpose computers,
such as calculators, digital watches and washing machines.
6) General purpose computers, such as PCs and laptops, also use ROM to store bootstrap programs that are
required to boot the computer.
7) ROM is generally used to refer to memory that cannot be changed after manufacture. Its full name is
Programmed Read Only Memory (PROM).
8) It is manufactured with the ability to be written to, but it can only be written to once, after that, the contents
can not be changed or removed.
Although the computer system cannot swap instructions in and out of ROM, it is possible to change the contents
of some special types of ROM so that the data on it can be updated. These types of ROM are called:
 EPROM (Erasable Programmable Read Only Memory)
 EEPROM (Electrically Erasable Programmable Read Only Memory).
The contents of EPROM and EEPROM can be erased and then rewritten to.
Data stored in EPROM can be erased by exposing it to strong ultraviolet (UV) light while data stored in EEPROM is
erased by applying a voltage to one of the pins on the ROM chip. This makes it possible to erase or change the
contents of EEPROM without removing the ROM chip.
EEPROM was later developed into flash memory.
The process of erasing and rewriting the contents of EPROM or EEPROM is used when updating the firmware for a
device.
Firmware is a type of software that controls a hardware device.
4) - Flash Memory
Flash memory is a type of EEPROM. Like other types of ROM, it is non-volatile but its contents can be altered by
the user. It does not have any moving parts, so it has a fast access time and low power consumption. Because of
its low power consumption, flash memory is used in the Solid State Drives (SSDs) that are used in portable devices,
such as laptops, as these devices often rely on internal batteries for their power. Flash memory is also used as
removable storage in flash disks and memory cards (SD cards).
Features of Flash Memory
• Flash memory has high access speed, which means that data can be written to or read from the device faster.
• The device is very small in size (compact).
• They are very Light in weight thus suitable to be used in portable devices such as tablets
• Have no moving parts unlike magnetic drives and optical drives
• They consume less power.
• They are more costly per GB
• Low storage capacity per unit cost
Difference Between RAM and ROM
RAM
ROM
1
RAM is Volatile
ROM is Non-volatile
2
Stores data temporarily
Stores data permanently
3
Can be upgraded
Can not be upgraded
4
Stores programs being executed
Store boot strap programs
Processors
The processor is the brain of the digital device. It carries out software instructions.
A processor is made up of one or more Central Processing Units (CPUs). In processors that are made up of more than
one CPU, each CPU is referred to as a core. For example, in a quad-core processor, four cores are working during
each processor cycle. This means that it can do up to four times as much work as a single-core processor.
In multi-core processors, each core can run more slowly than in a single-core processor. This saves energy and
produces less heat, which means that the processor requires less cooling. This makes the computer quieter as the
fan does not have to cool the system.
Reducing the amount of time in which the fan is running also reduces the amount of energy that the system uses,
making the system more environmentally friendly and further increasing the battery life of mobile devices.
Processors
The processor is the brain of the digital device. It carries out software instructions.
A processor is made up of one or more Central Processing Units (CPUs). In processors that are made up of more than
one CPU, each CPU is referred to as a core. For example, in a quad-core processor, four cores are working during
each processor cycle. This means that it can do up to four times as much work as a single-core processor.
In multi-core processors, each core can run more slowly than in a single-core processor. This saves energy and
produces less heat, which means that the processor requires less cooling. This makes the computer quieter as the
fan does not have to cool the system.
Reducing the amount of time in which the fan is running also reduces the amount of energy that the system uses,
making the system more environmentally friendly and further increasing the battery life of mobile devices.
Processor Speed
Processor speed is measured in clock cycles per second. This is the number of times per second the processor can
carry out one or more instructions. Clock cycles are measured in units called hertz (Hz), Kilohertz (KHz), megahertz
(MHz) and Gigahertz (GHz).
Although clock cycles measure processing speed, there are other factors that affect how much work a processor can
do in a given time. A user should also consider the amount of work that a CPU can do in each clock cycle. Different
processors can carry out more instructions per core in each cycle.
Connectivity
Digital Communication
 Our world is connected by wired and wireless digital communication systems. Data flows around these
systems, carrying information about our personal and work lives and providing us with entertainment and
news. Digital devices exchange data and communicate with each other.
 Digital Communication refers to the way digital devices transmit data to one another.
Terminology
 Network – set of interconnected digital devices that able to communicate and share resources.
 Node – Any device connected to the network e.g. computers, routers, switch, printer, etc.
 Work station a computer connected to the network.
 Stand-alone Computer – A computer not connected to the network.
 Server – main computer in a network that controls other devices in the network.
 Client - computers in a network which are controlled by the server.
 Bandwidth – amount of data that can be transmitted across a connection per unit time.
 Latency – the time it takes to send data from one device to another.
Speed & Volume of Data Transfer
The digital world in which we live has experienced a great increase in the amount of data to be transferred among
devices. This has led to the need to understand ways of increasing the speed at which this large volumes of data can
be transmitted.
The following are important terms to understand as far as data transmission is concerned are;
 Bandwidth
 Latency
 Domain – name used to identify a web server
Buffer - refers to an area in the memory of a digital device used to temporarily store data especially when streaming
Bandwidth is the amount of data in bits that can be transferred across a connection in one second.
 The speed at which data can be transferred depends on the bandwidth of the connection.
 Like a water pipe. The larger the pipe the more the amount of water the pipe can carry in a second.
 Impact on user Experience:
 A higher bandwidth means that more data can be transferred per second. This makes upload and
download faster. It makes it possible to do things that require lots of data to be transferred in short
time e.g. multiplayer online games or high definition video streaming.
Latency is the amount of time it takes to send data between devices.
 Like in a pipe of water, latency is the average amount of time it takes for a drop of water to flow through the
pipe
 We identify latency by pinging a domain.
 Pinging is sending a packet of data to a server and the packet is immediately returned by the server. The Ping
time is the amount of time for the packet to make the return trip.
 Impact on user Experience:
 In online games the game will play smoothly if the bandwidth is adequate. However, if latency is high,
events in the game will lag making the game not enjoyable.
Factors Affecting the Speed and Volume of Data Transfer
 When devices transfer data, they can be affected by many factors that stop bits from reaching their
destination. These bits then have to be sent again which slows the overall transfer rate.
 These factors include;
1) Transfer method – Wireless methods work on a limited number of frequencies unlike wired methods thus
wired methods have more bandwidth and can transmit faster.
2) Interference – other electromagnetic signals interfere with signals being transmitted thus slowing the
transmission
3) Blockages – walls and furniture may reduce the strength of the signals thus reducing the bandwidth
4) Distance – signal get weaker as they travel longer distances.
Forms of Digital Communication
Digital Communication refers to the way digital devices transmit data to one another.
 Digital devices can communicate in these forms;
1) Device-to-device Communication - Where devices connect directly to each other using wired or wireless
methods.
2) Network Communication – Where devices connect together to form a network
Device-to-device Communication
This is where devices connect directly to each other using wired or wireless methods.
Examples of device to device communication
Network Communication
This is where two or more devices are connected to create a network so that they can exchange data.
A network is a set of interconnected digital devices that are able to communicate and share resources.
 Resources that can be shared on the network include;
 Data
 Files
 Printers
 Storage devices
 Programs
 Internet connections
Types of Networks
 Local Area Network (LAN)
 is a network that connects digital devices that are in a small geographical area, like a building or group
of buildings close to each other.
 Wide Area Network (WAN)
 network that spreads over a large geographical area. They often use connectivity provided by thirdparty telecommunication companies to link LANs together through the internet.
 Due to their big size, they often have slower transfer speeds compared to LANs.
 Internet is the largest example of a WAN.
 Personal Area Network (PAN)
 is a group of connected digital devices that are all for to be used by an individual.
 Devices in a PAN are either connected to each other directly or connected through access points.

Campus Area Network (CAN)
 network that covers multiple buildings in a large institution such as a university campus.
Ways in Which Digital Devices Communicate
 Whether it is device to device or network communication, digital devices have several ways in which they
transmit the data from one to another.
 These are methods that digital devices use to share data with their common uses
Satellite Communication
This is a wireless transmission technique where satellites are used to transmit data from one device to the other.
Digital devices use antennae to receive the radio signal transmitted by satellites.
Benefits
 the transmission is very reliable and will always be available.
 It is also not affected by power shortages.
Drawbacks
 is that satellite signal do not pass through solid objects thus it needs line of sight.
 Signals can also be affected by atmospheric weather conditions such as heavy rains or snow
Satellites are used in GPS, television, telephone and military communication systems.
Satellite Communication in GPS
Satellite communication can be used in navigation aids that make use of GPS signal to calculate that exact location
of a device.
GPS signals are sent from a network of 24 satellites orbiting from the earth. Only 4 satellites are required to
calculate an accurate location.
Satellite Communication in Television
Digital Video Broadcasting – Satellite (DVB-S) is the internationally accepted standard method of broadcasting
digital television.
A video signal from the broadcaster is transmitted using a large antenna on Earth to the satellites which then
broadcast the signal back to the earth. A satellite TV viewer will have an antenna which receives the signal.
Satellite in Telephone Communication
Satellite communication is also used to allow people in remote areas to place voice calls using satellite telephones.
Satellite Communication in Military
Military departments in many countries use satellites for communication systems such as the Global Command and
Control Systems.
Broadcast Communication
Broadcast communication is a wireless communication commonly used in both Analogue and digital television and
radio communication.
In Analogue Tv and Radio, the analogue signal is broadcast by transmitters and received by the viewer’s antenna which
sends the signal to the TV or radio which converts it into images and sound.
Digital broadcast is similar to analogue but may provide more information as well as transmit HD video signals
Wired Communication
Wired communication refers to a form of communication that involves devices transmitting information through
cables connected to the devices. The following are examples of commonly used wired Connections with some
examples of their uses;
Wired Connection Type
Example of the Use
HDMI (High Definition Multimedia
Interface)
Digital Video Connections e.g. Laptop to TV
Minijack
Person headphones
USB
Storage Connections e.g. External hard disk to TV
Ethernet
Networking
S/PDIF (Sony/Philips Digital
Interface)
Audio Digital Connections
Ethernet
 allows a user to connect to wired networks. As Ethernet technology develops, the speed at which data can be
transferred between devices is improved.
 Ethernet cables can go for a maximum of 100m
USB
USB is a very common connection type. It is a standard that is common with all types of connectivity.
This progress is made necessary as digital devices become more complex in their features and functionality.
HDMI (High-Definition Multimedia Interface)
 HDMI is a proprietary audio and video interface for transmitting video data digital audio data from device to
another, such as a display controller, to a compatible computer monitor, video projector, digital television, or
digital audio device
Minijack
A minijack connector, also known as phone jack, audio jack, headphone jack or jack plug, is typically used for analog
audio signals. E.g. from phone to headphones.
Wireless Communication
Digital devices can communicate wirelessly to one another. This is where devices transmit data from one to another
without any physical connection such as cables.
There are many different types of wireless connections;
 Wi-Fi
 Bluetooth
 Wi-Fi Direct
 Infra-Red (IR)
 Near Field Communication (NFC)
 3G/4G
Wi-Fi
Wi-Fi is a wireless technology used to connect devices to a network.
It is commonly used in home and office networks. Wi-Fi networks can then be connected to the Internet.
Wi-Fi technology can transmit signals to a long distance though the range is limited depending on the strength of the
transmitter.
It has a high transmission bandwidth thus can transmit faster
Wi-Fi transmission does not require line of sight.
It can connect many devices at a time.
Bluetooth
 Is a type of wireless connectivity that allows devices to connect over a short distance. It has less bandwidth so
it cannot transmit as much data as Wi-Fi.
 It requires devices to pair before they can communicate.
 Bluetooth is used to transfer small files between two devices. It can also be used to connect devices such as
smartphones, tablets and laptops to earphones, keyboard, mice, printers, etc.
Wi-Fi Direct
Infra-Red (IR)
 Is a wireless transmission technique that transmits small amounts of data over a short distance.
 The transmission requires a clear line of sight between the transmitter and the receiver.
 Line of sight refers t a situation where the two devices (transmitter and receiver) are in a place where they are
not blocked.
 This allows the signal to travel between them without being blocked by solid objects like walls.
 IR signal is also affected by sunlight.
 IR often used in remote-control devices such as TV remote controls
Near-Field Communication (NFC)
 This is a wireless communication technic that uses close proximity RFID (Radio frequency Identification) chips.
 It that enable two electronic devices to establish communication by bringing them within 4 cm.
 This is sometimes referred to as NFC/CTLS (Contactless).
 NFC is used in smartphones, payment cards and travel cards.


Also used in social networking, for sharing contacts or files.
NFC-enabled devices can act as electronic identity documents and keycards.
3G and 4G
 Is a wireless transmission technic used to provide Internet access to mobile devices such as smartphones and
tablets.
 Also referred to as mobile broadband.
 The G stands for generation – thus 4G means fourth generation of mobile broadband technology.
 Future generations of broadband technology will improve the speed and availability of the signal.
 Mobile broadband provides high-speed wireless connectivity using 3G or 4G technology to connect to the
mobile phone network which acts as the user’s ISP.
 Broadband networks provide fast access to the internet through a connection to an ISP. They use fiber optic
cables or copper cable network.
Comparison Between Wi-Fi and Bluetooth
Wi-Fi
Bluetooth
Range
Can transmit over a long distance
Transmits over short range. (maximum of
10M)
Bandwidth
Has a high bandwidth
Has a low bandwidth
Power Consumption
Consumes more power
Consumes less power
Security
High level of security
Low level of security
Devices Connected
Simultaneously
Can connect multiple devices
simultaneously
Connects a limited number of devices usually
two. (pair)
Advantages of Wi-Fi over Bluetooth
 Can transmit over a long distance
 Has a high bandwidth which means it can transmit more data per second compared to Bluetooth.
 High level of security – Wi-Fi allow devices to connect in a more secure way where users need to have a
security key before connecting.
 Can connect multiple devices simultaneously while Bluetooth can only connect two devices at a time.
Disadvantages of Wi-Fi over Bluetooth

Wi-Fi connections consume more power than Bluetooth transmission.
Comparison of Wired & Wireless Transmission
Networks
Requirements of Connecting to Networks
Protocols
In order to connect to a network, computes need to fulfil certain requirements so that they all operate using standard
protocols. Protocols are rules that allow the exchange and transmission of data between devices.
Network Operating Systems
A network operating system allows a computer to communicate on a network by providing additional functionality to
a standalone OS which includes: Passing usernames and passwords to a server for authentication
 Separating user accounts and ensuring users cannot access each other’s files.
 Providing access to a network storage and shared resources such as networked printers.
Identifying Devices on a Network
 For devices to successfully communicate on the network, there must be a way to uniquely identify each
device.
 There are three main ways of uniquely identifying devices on the network;
 Internet Protocol (IP) Address
 MAC Address
 Device Name
IP Addresses
 An IP address is a unique address that networked devices use to send data to each other. Each piece of data
sent across a network carries an IP address of the destination host so that each device on the network knows
where to send it.
 IP addresses are made up of groups of numbers and are categorized into two main versions: IPv4 - Uses four groups of up to three numbers separated by full stops e.g. 192.168.1.1.
It can store over 4billion addresses and was developed because of the huge growth in number of connected devices.
 IPv6 – Uses eight groups of four hexadecimal numbers separated by colons e.g.
f02e:0db8:0000:0042:0000:8a2e:0370:7334.
 IP addresses can either be assigned by a network administrator or allocated dynamically by a server running
Dynamic Host Configuration Protocol (DHCP).
 A DHCP server is a networked computer that automatically assigns an IP address to other computers when
they join the network.
 Commonly used with wireless devices such as smartphones and tablets.
Media Access Control (MAC) ADDRESS
 These are universally unique identifiers given to the network interface card (NIC) and are not dynamically
allocated by users or servers. They are used in devices connected to LANs using Ethernet, Bluetooth or Wi-Fi.
They are assigned by the NIC manufacturer and are fixed addresses. It is made up six pairs of characters, the
first three identifies the manufacturer and the remaining part uniquely identifies the device.
 MAC addresses can be changed through a process called spoofing which means using a MAC address of
another device.
Uses of MAC Addresses
1) Restricting access to a network
2) Identifying a device on a network
3) Tracking a device
4) Assigning static or fixed addresses
Uses of MAC Addresses
1) Restricting access to a network - MAC address filtering checks the MAC address of devices attempting to gain
access to a network and grants only specified MAC addresses.
2) Identifying a device on a network – MAC addresses provide a very unique way to identify each device that
connects to a network.
3) Tracking a device - Some companies track devices by checking which WAP have been accessed by specific MAC
address.
4) Assigning static or fixed addresses - Each time a device connects to a network, it is identified by a DHCP server
and given the same IP address.
Device Name
A device name is a descriptive name that helps users to identify computers on a network. They are not used by
computers to communicate with each other as they are not always unique i.e. they can cause conflicts if data is sent to
more than one device with the same name for processing. You can change a device name using tools in the devices
operating system.
Components Of Wired Systems
Physical Transmission Media - allows the transmission of data in a network. It can be an Ethernet network cable,
Coaxial copper wires or Fiber cable. Fiber Optic cables are flexible fibre containing a glass thread that bounces light
signals between two devices faster and further than an Ethernet cable an can also carries data at 40 Gbits/s over many
kms without affecting signal quality.
Ethernet Cable
Coaxial Cable
Fibre Optic Cable
Components Of Wired Networks
 Routers - stores the addresses of all devices that are connected to it so that it can forward network traffic to its
destination using the quickest route. Most routers used in homes include a switch and a wireless access point.
They also act as gateways, connecting the LAN to the internet, which is a type of WAN. Home routers are
dynamically allocated an IP address by the internet service provider (ISP).
 Gateway - A gateway connects two different types of network. For example, a LAN is connected to a WAN using a
gateway.
 Switch - connects devices on a network. It has ports, each of which can be connected to a device using a cable.
Connecting a wireless access point to a switch via a cable gives wireless devices access to the wired network. The
switch makes sure that data sent from any device gets to the correct device on the network. For example, when
printing a document, a laptop will send data that includes the printer's IP address to the switch and the switch
then sends the data to the connected printer.
 Firewall - A firewall is hardware device or software that protects your internal LAN network from any external
attacks from the internet.
 Booster – Used to amplify the signal in a network so that its range can be extended. Wireless Access Points can be
set to repeater mode to act as a booster for Wi-Fi signals.
 Bridge - A bridge is a network device that typically links together two different parts of a LAN.
 Modem – A device which converts analogue telephone signals into digital computer signals.
Server
 This is a powerful computer on the network that shares its resources with connected devices. Computers
connected to a server are known as clients.
 Types of servers;
1) A File Server stores all data and software that are shared in the Network.
2) An e-mail server will store all e-mails and also receive all e-mails then transmit them to each user.
3) A Proxy Server - a computer setup to share a resource, usually an Internet connection.
4) Authentication Server – checks usernames and passwords When a user logs in the network, if the password
and username are correct, then the client is allowed to access resources on the network.
5) Application Server – Provides clients with access to application softwares that are installed on the server.
6) Print Server – Manages printers in a network, dealing with print requests from client computers and adding
jobs to a queue to avoid overloading the printer with requests.
7) Web Server – this is where web pages are hosted. It enables client computers to access the web pages even
from outside the LAN by using HTTP.
Components of Wireless Network
A wireless network is a network in which nodes are connected without any physical media. The devices are able to
communicate with one another through wireless transmission techniques such as wi-fi, Bluetooth, NFC, Infrared, etc.
Wireless networks use the following components;
1. Wireless Access Point (WAP)
2. Wireless Network Interface Card (WNIC)
3. Wireless repeaters or wireless range extender
4. Wireless Router
 Wireless Access Point (WAP) - It connects a group of wireless devices together then links them to wired LAN. It
conveys data between connected wireless devices and one connected wired device, such as a router or switch,
thus allowing wireless devices to communicate among themselves or with other wired devices.
 Wireless Network Interface Card (WNIC) - It allows devices to connect to a wireless network. Most new laptops are
equipped with internal WNICs.
 Wireless routers - A wireless router allows wireless LAN devices to connect to a wired device such as a modem so
as to connect to internet. Some wireless routers come with a few LAN ports the enable wired devices also to
connect to the internet.
 Wireless repeaters (wireless range extender) - Is used to extend the range or boost/amplify the signal of an
existing wireless network. They can be strategically placed to elongate a signal area or allow for the signal to reach
around barriers such as those created in L-shaped corridors, Mountains and also tall buildings.
The Internet
 The Internet is a global system of interconnected computer networks that use the standard Internet Protocol
Suite of protocols (TCP/IP) to serve billions of users worldwide.
 It is a network of networks that consist of millions of private and public, academic, business, and government
networks that are linked by electronic and optical networking technologies.
 The Internet carries a big amount of information resources and services, most notably the inter-linked
hypertext documents called the World Wide Web (WWW). It also has the infrastructure to support electronic
mail.
The Internet Protocols
Protocols are used by applications to transfer data across the internet e.g.
 IMAP (Internet Message Access Protocol) for managing email.
 FTP (File Transfer Protocol) for sending files over the network.
 SSH (Secure Shell) for secure remote logins into a network
 VoIP (Voice Over Internet Protocol) enables voice call services done over the internet. E.g. Skype
 XMPP (Extensible Messaging Presence Protocol) used for messaging services like WhatsApp.
 HTTP (Hypertext Transfer Protocol) used for the www
Requirements for Connecting to the Internet
In order to access the online services provided by servers and data centres, users must have a connection to the
internet. Users also need software that allows them to use and work with the services effectively and safely.
1. Web browser – Application used to request and display information stored on web servers. E.g. Mozilla
Firefox, Google Chrome, Internet Explorer® or Microsoft Edge, Opera", and Safari®9
2. Internet Service Provider (ISP) - provide connections to the telecommunications infrastructure that forms the
framework for the internet. Commercial ISPs charge subscription fees for access to the internet. Some ISPs
provide free access as part of community schemes, which aim to provide internet access to groups of residents
who either do not have or do not want access to commercial ISPs.
3. Search Engine – Provide users with a way of finding information in web pages stored on web servers. Users
enter keywords that describe the information they want to find and the search engine will compare the
keywords with those in its database and return results that are closest to the given keywords.
4. Filter Software – Prevent users from accessing inappropriate information. When accessing a web, the URL and
contents of the web are compared against two lists (Whitelist and Blacklist) of URLs and keywords stored in
the filter software’s database.



If the results match anything in the blacklist, the user will be denied access to the web page.
If the result matches anything in the whitelist, the user will be allowed to view the web page
If the result does not match anything in either the blacklist or the whitelist, the user will be allowed to
view the information.
Internet Services
1. World Wide Web (WWW) - interlinked hypertext documents (Web pages) stored on the webserver to be
accessed via the Internet.
2. E-mail - is a service provided by the internet to enable users to send and receive messages quickly and
securely through an electronic or computer channel.
3. News groups - is a service that provides a repository for messages posted from many users at different
locations.
4. Internet forum - is a web application for holding discussions and posting user-generated content. They are
also referred to as Web forums, message boards, discussion boards, discussion groups, discussion forums,
bulletin boards, or simply forums.
5. Chat rooms – is an internet service that gives users a way of communicating by sending text messages to
people in the same chat-room in real-time. Some chat rooms such as Yahoo! use both text and voice
simultaneously.
6. Instant messaging (IM) - is a form of real-time communication between two or more people based on typed
text conveyed via computers connected over a network.
7. Search engines - A search engine is an information retrieval system designed to help find information stored
on the www. Search engines help to minimize the time required to find information and the amount of
information which must be consulted, akin to other techniques for managing information overload. Other
kinds of search engines include enterprise search engines, which search on intranets, desktop search engines,
and mobile search engines.
8. Internet filter software – is a service that gives one the ability to control content displayed, block websites
and set up passwords. Powerful services like email filtering, popup blocking and chat room monitoring are just
some of the tools available with today's internet filter software, each designed to protect against and
counteract the tactics of aggressive malicious online companies.
Local Area Networks (LANs)
A LAN is a network that connects digital devices that are in a small geographical area like a building or group of
buildings that are close to each other.
Benefits of Using LANs
 Access to shared peripherals
 Access to shared storage and data
 Flexible access i.e. being able to access peripherals, storage and data from any connected device.
 Media streaming
 Facilitates communication
 Shared access to the internet.
Types of LANs
Devices in a LAN can be connected using these two types of models.
 Client-server (server-based) Network
 Peer-to-peer
Peer to Peer LANs
 Devices are connected together so that users can share resources and information with one another without
the control of the server.
 There is no central location for authenticating users, storing files, or accessing resources thus users must
remember which computers in the workgroup have the shared resource or information that they want to
access.
 It also means that users must log on to each computer to access the shared resources on that computer.
 In most peer-to-peer networks, it is difficult for users to track where information is located because data is
generally stored on multiple computers.
 This makes it difficult to back up critical business information, and it often results in small businesses not
completing backups.
 Often, there are multiple versions of the same file on different computers in the workgroup.
Client-Server LANs
 In a server-based network, the server is the central location where users share and access network resources.
 This dedicated computer controls the level of access that users have to shared resources.
 Shared data is in one location, making it easy to back up critical business information.
 Each computer that connects to the network is called a client computer.
 In a server-based network, users have one user account and password to log on to the server and to access
shared resources.
 Network Server Operating Systems are designed to handle the load when multiple client computers access
server-based resources.
Benefits of Using Client-Server LANs
 Control of user access rights – Users can be given access to some resources and restricted from accessing
others.
 Centralized administration – Resources and user accounts can be managed by a server or administrators
hence avoiding problems in the network.
 Centralized Backup – User data is protected from loss because backups can be automated for all users in the
network.
 Shared software – Application servers can provide access to shared software.
 Shared storage and file access – The amount of storage available to users can be managed centrally.
 Roaming profiles – Ability to log into any computer in an office and see your settings and files hence allowing
users to access data, applications and printers from any client.
Securing Data on the Network
Network security refers to any activities designed to prevent unauthorized users from accessing network resources
and data. Specifically, these activities protect the usability, reliability, integrity, and safety of your network and data.
Effective network security targets a variety of threats and stops them from entering or spreading on your network.
Many network security threats today are spread over the Internet. The most common include:
 Viruses, worms, and Trojan horses
 Spyware and adware
 Zero-day attacks, also called zero-hour attacks
 Hacker attacks
 Denial of service attacks
 Data interception and theft
 Identity theft
Network Security Components Include:
1) Updated Anti-virus and anti-spyware – to prevent attacks to your computer from viruses and malware.
2) Intrusion Prevention Systems (IPS) - to identify fast-spreading threats, such as zero-day or zero-hour attacks
3) Virtual Private Networks (VPNs) - to provide secure remote access to a private LAN.
4) Log-ins and passwords - this is where users are required to provide a secret code before logging into the
network
5) Setting of Firewalls – firewall is a device or set of devices configured to permit or deny information in or out of
the network based upon a set of rules and other criteria.
6) File access rights
7) Transaction logs
8) Backups
9) Encryption
Benefits of Network Security
1) Your company is protected against business disruption, which helps keep employees productive.
2) Network security helps your company meet mandatory regulatory compliance.
3) Because network security helps protect your customers' data, it reduces the risk of legal action from data
theft.
4) It helps protect a business's reputation.
5) Customer trust - A strong security stance assures customers that sensitive information, such as credit card
numbers or confidential business details, will not be accessed and exploited. Your business partners will feel
more confident sharing data such as sales forecasts or pre-release product plans
6) Mobility - Strong network security lets your employees safely access your network from the road or from
home without introducing viruses or other threats.
7) Improved productivity - An effective network security program can boost productivity across your
organization. Employees spend less time on non-productive tasks such as sifting through spam or dealing with
viruses
8) Reduced costs - Network downtime is costly to all types of businesses. By ensuring your network and your
Internet connection are safely up and running, you can be sure that customers can reach you when they need
you.
Drawbacks of Network Security
1) Cost – expensive to set up the hardware and software components.
2) Inconvenience – repetitive task of entering and confirming passwords can be cumbersome.
3) False sense of security – some admins will stop checking on the logs when they have implemented the security
features in their networks hence risks of attacks.
Encryption
Encryption is the process of encoding, scrambling or jumbling data so that unauthorized users are can’t understand it.
Caesar cipher was one method used to encrypt data whereby it shifts letters to the left by a set number of places.
Caesar cipher is easy to crack hence the need to have modern encrypting types/methods.
Two types of encryption are:a) Symmetric key encryption - It uses the same key at both ends of the process, meaning that the same key is
used to encrypt and decrypt the data.
b) Public key encryption - It uses two related keys called a key pair, one key is used to encrypt while the other is
used to decrypt it. A computer shares a public key with other computers that want to send it encrypted data.
This public key is mathematically related to a private key, which is not shared. E.g. If Farooq wants to send
Aisha an encrypted message, Farooq uses Aisha’s public key to encrypt the data. Data is then sent to Aisha,
who uses her private key to decrypt the message.
Examples of Encryption Key
 Wireless Encryption Protocol (WEP) - is used to secure data transfer in a wireless network. It’s less secured
because every device on the wireless network uses the same key for every transfer.
 Wi-Fi Protected Access (WPA) - Is a security protocol designed to provide better encryption than WEP. WPA
generates a new key for each device on the wireless network and for each packet of data that is sent.
Operating Online
Unauthorized Access
•
•
This is where users who are not permitted to access a network gain access to that network.
Unauthorized users attempt to gain access to networks either directly or by use of programs that run numerous
login attempts on devices attempting to gain access to the networks with poor security.
Deliberate Damage By Malware
 The term Malware is a short form for Malicious Software.
 These are software programs meant to do malicious things to harm the data, system or the connected hardware.
 Malicious users may infect the system with one form of malware or the other with the intention of destroying or
misusing information stored on the system
Theft of Personal Data
Malicious people may use a number of methods to gain access to sensitive personal information with an intention to
defraud the owner of the information.
Commonly used methods include;
• Phishing
• Pharming
• Spyware
• Smishing.
Phishing
A technique used by criminals to get personal information and payment details from users by sending e-mail messages
that appear to be from real organizations, such as shops, banks or charities. These emails ask the user to provide their
information by replying to the message or following a hyperlink that opens a webpage into which the user is asked to
type their personal details.
Spear phishing is where the emails are highly customized or personalized and targeted at a smaller number of
particular users.
Smishing is where the messages are sent via SMS or instant message apps so that users open the fake webpage in a
mobile browser. Users may not realize that the webpage is fake, particularly if they have never seen the company's
real webpage in a mobile browser. As a result, they might type in their username and password details and reveal this
personal data to the criminals.
Pharming
A technique used by criminals to gain personal information from users by creating fake versions of trusted websites to
trick users into entering their login details, which are then used by the criminals to access users’ accounts. Two main
methods used to direct users to a pharming site are :•Internet traffic going to the real website is redirected to the fake website, so that users think they are visiting the real
thing. Criminals do this by altering the domain name servers to make internet traffic go to their fake site. They can also
use malware to redirect web requests.
• Often, the URL of a pharming website is designed to be very similar to the URL of the real website. This means that if
a user misspells the URL when typing it into the address bar of their web browser, they could go to the pharming site
by mistake. For example, if the URL of a real bank is https://moneybank.lk and the criminals create a website with the
URL http://moneybamk.lk, it could be easy for the user to make a mistake and arrive at the fake website.
Spyware
A technique used by criminals to gain personal information from users by sending a malicious program to the users
system to secretly capture personal information.
Key logger are spyware programs that monitor key presses on the keyboard to capture sensitive information such as
passwords.
Methods of Securing Data & Information Online
Much of the data transmitted online is sensitive and valuable, and it is important to protect that data from
unauthorized access. There are several different methods used to secure data and personal information. These
include;
 Firewalls
 Encryption
 Passwords, PIN and Biometrics
 CAPTCHA
 Anti-malware
 Access rights
 Secure websites
 Backup Procedures
Firewalls
A firewall could be a hardware device, a software program or both.
Firewalls are frequently used to prevent unauthorized users from accessing private networks and computers
connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall,
which examines each message and blocks those that do not meet the specified security criteria.
Encryption
Is a process of encoding, scrambling or jumbling data so that it is not understandable to unauthorized users. Caesar
Cipher was one method used to encrypt data whereby it shifts letters to the left by a set number of places. Caesar
cipher is easy to crack hence the need to have modern encrypting methods. There are two types;
 Symmetric Key Encryption - uses the same key at both ends of the process, i.e. the same key is used to encrypt
& decrypt the data.
 Public Key Encryption - It uses two related keys, one for encryption and the other for decryption.
A computer shares a public key with other computers that want to send it encrypted data. This public key is
mathematically related to a private key, which is not shared.
Encryption Protocols
 Wireless Encryption Protocol (WEP) - It is used to secure data transfer in a wireless network. It’s less secured
because every device on the wireless network uses the same key for every transfer.
 Wi-Fi Protected Access (WPA)/WPA2 - Is a security protocol designed to provide better encryption than WEP.
WPA generates a new key for each device on the wireless network and for each packet of data that is sent.
Password, PIN and Biometrics
Passwords, PINs and biometrics are used online to authenticate a user so that they can access an online system, such
as webmail or online bank account. Passwords and PINs are masked to avoid being seen. Some services allow the
password to be remembered though not recommended for multiple users of computers with stand-alone operating
systems. Network operating systems are more secure as it will not allow different users to see each other’s password.
Features of a Strong Password
Users should make sure their passwords are more secure by: More than eight characters long
 A mix of letters, numbers and symbols
 A mix of uppercase and lowercase
 Made up of random characters i.e. not words, names or DOBs.
 Changed frequently
Captcha Tests & Security Questions
Used to make sure data is entered by a human and not by an automatic software program known as a bot or a web
robot. CAPTCHA stands for Completely Automated Public Turing Test To Tell Computers and Humans Apart.
Some CAPTCHA tests work by asking users to enter a randomly generated series of letters/numbers displayed on the
screen.
Automatic software cannot read the letters displayed, or enter them into the required field, so this is used to
distinguish human users from robots.
reCAPTCHA Tests
work in the same way but use extracts of text from scanned books or a selection of images that share common
features.
When a user solves a reCAPTCHA test, their solution is used to help digitize books and annotate images. This helps to
make more books available online and improves the information provided in online maps and other services
Anti-Malware Programs
Anti-malware prevents malware from accessing or operating on computers. It scans computer files in real time and
allows users to scan files, folders, disks or whole systems.
Common Anti-Malware Programs Include;
1) Updated Anti-virus software
2) Anti-adware - Adware displays unwanted adverts to users. Anti-adware software detects, Quarantines &
removes adware
3) Anti-spyware - Spyware secretly monitors and records computer data and user input. E.g. a keylogger is a type
of spyware that monitors and records actions such as key presses or mouse clicks to identify a user's
passwords and security codes. Anti-spyware software detects, quarantines and removes spyware.
Anti-Virus Programs
A virus is malware that uses networks to spread to connected devices. They are spread via communication software
such as email or web browsers or by being loaded into a computer's memory from external storage such as USB flash
drives. Viruses often look like normal files. However, they have unique virus definitions that can be identified by antivirus software.
Updated Anti-virus software constantly checks files that are downloaded and loaded by a computer for signs of virus
definitions. If the anti-virus software finds a match, it quarantines the file so that it cannot be run. Anti-virus software
has to be updated regularly because virus code can be changed, either automatically or by the developers of the virus.
Anti-virus utilities are often combined with software that protects against adware and spyware thus often known
more generally as anti-malware.
Access Rights & File Permissions
Permissions can be set for access to files, folders or drives, allowing users to read only or read and write to a file.
Secure Websites
Hypertext Transfer Protocol (HTTP) is used to exchange data between a web server and a client (that is, a computer
that is accessing the web server). However, data transferred using HTTP is not secure, so Hypertext Transfer Protocol
Secure (HTTPS) was developed. HTTPS authenticates payment servers and provides encryption using Secure Socket
Layer (SSL) and, more recently, Transport Layer Security (TLS). HTTPS keeps communications private and provides
security for users' online accounts. Web browsers often show that a website is secure by displaying a green padlock in
the address bar.
Email Attachments & Web Links
Another way of securing data & personal information online is by users being careful when opening email
attachments or hyperlinks in emails especially when: They do not recognize the sender
 Text is irrelevant
 Text has grammatical errors
 File is executable file like .exe
 User does not recognize the URL.
Backup Procedures
This is creating of extra copies of data on an external storage device or online storage where the data will be held on
two different geographical locations. Online backing storage is slower because it uses an internet connection.
During backup, users need to decide on;
 how many or which files to back up and
 how often to backup.
Three types of backup include: Full Backup – creates a copy of all files
 Differential Backup – creates a copy of all files that have changed since the last full backup
 Incremental Backup – Saves a copy of only the files that have changed since the last full or differential backup.
Good Ideas For Backup Procedures
 Set automatic backups.
 Do not use optical media because they deteriorate over time and are fragile.
 Schedule backups for late in the evening when users will not be using the data that is being backed up in order
to avoid conflicts.
 Create more than one copy.
 Keep one copy of a folder containing important files backed up using online storage
 Store copies at multiple locations.
 Store important data in a fireproof safe.
Online Payment Methods
Online Payment systems send payment details across networks to computers that process the payments using the
following methods:i.
Online Third-Party Payment Processors – Such as Paypal, Skrill
ii.
Bank Cards – credit and debit cards
iii.
Contactless Cards Using NFC
Third-Party Payment Processors
Online third-party payment processors like PayPal or Skrill allow users to create an account so that they can send and
receive money using email accounts for identification. Users can also use systems that link with online shopping
applications, which can make shopping easier and faster.
Bank Cards
Bank cards allow customers to pay for goods and services online and in shops. You need to enter the following details
when paying online using a bank card:
 Card Number
 Expiry date
 Name on the card
 Card Security Code (CSC), Card Verification Code (CVC) or Card Verification Value (CVV)
Contactless Cards Using NFC
Near field communication (NFC) is used in payment cards to allow the transfer of payment
data. The payment does not require a PIN or any form of user authentication. If a card reader
is in range and requesting payment, then the contactless card will take payment up to a
maximum amount. This amount is limited, so that any people using card readers or apps to
commit fraud can only steal a small amount. NFC cards can be wrapped in foil to prevent the
very weak signal from being intercepted by criminals.
Operating Online
Impacts of the Internet
The Internet
The Internet is the interconnected network of computers and devices that provides many online services to
users.
The World Wide Web is just one use of the internet. Protocols are used by applications to transfer data
across the internet.
These protocols include:
• IMAP (internet message access protocol) for email
• FTP (file transfer protocol) for sending files
• SSH (secure shell) for secure remote logins
• VoIP (voice over internet protocol), used for voice call services like Skype
• XMPP (extensible messaging presence protocol), used for messaging services like WhatsApp
Impact of the Internet on Individuals
The use of Internet has numerous impacts on an individuals life. It affects the ways people carry out their
lives in the following ways;
Information and Services
 It has improved access to information from news, sports and weather services as info is up to date
and spreads fast.
 Access to online booking systems for travel, leisure and entertainment.
 Online shopping and banking.
 Study using Virtual Learning Environments (VLEs)
Employment
 Skill requirement - Use of Internet has made many employers to require employees to use internet
for work meaning employees need to learn new skills.
 It has created new job opportunities since skilled workers are needed to support this development.
 If employees do not keep updating their skills in the use of the internet, they may not have the skills
required to carry out new work and they could lose their jobs.
Working Practices
It has affected the ways in which people carry out the tasks in the course of their working. These include;
 Collaborative Working - enables people to connect with one another in real time where work is split
into a number of individual tasks each of which can be done by different employee at the same time.
Benefits:
 Each employee can focus on one task.
 Employees become experts in their area of work through experience or training.
 Expertise is shared
 Employees can share work
Drawbacks: Employees do not share their skills and expertise
 Employees have less understanding of the whole project.
 Difficult for many people to agree.
 Difficult to co-ordinate work.
 Flexible Working - A way of working that enables an employee to decide the hours that he/she can
work from home. Can also allow more than one person to work on a task at the same time.
Benefits: Can work at appropriate time while taking breaks.
 Employees can fit their work around family life.
 Access to up-to-date information
 Can work from anywhere with internet connectivity
Drawbacks: No face to face interaction
 Work cannot be managed effectively.
 Can cause exhaustion if overworking
 No access to the same facilities or resources.
Teleworking
Teleworking refers to a practice where employees work from their homes or a telecentre and use a
network, internet (E-mails, video-conferencing and mobile phones) to communicate with the office
instead of travelling to the office every day.
Teleworking is also referred to as telecommuting. The use of ICT has enabled many companies to use
this method of working and it has many benefits to the employers (company) as well as to the
employees (Individuals).
Advantages of Teleworking to Workers (Employees)
1) Reduced stress – employees don’t have to travel or drive for long distances and wake up very
early to avoid traffic on their way to work.
2) Saves travelling time which can be used in working and relaxing
3) Reduced expenses for traveling and clothing
4) Employees can work at their appropriate and convenient time
5) They have the privilege of working in the comfort of their homes.
Advantages of Teleworking to Workers (Employees)
1)Distractions from family members, neighbors, pets and household chores.
2)There is limited interaction with fellow workers
3)Lack of access to specialist facilities and advice that may only be available at the work place.
4)Limited contact with the employer may make the employee fear being overlooked for promotions.
5)The employee may be required to buy the equipment necessary for teleworking which may be
costly.
Advantages of Teleworking to Company (Employer)
1) It will help the company to attract and maintain good workers even if their families change
residence.
2)
The company is able to hire workers from all over even from a different country.
3)
There is a reduction in sick leaves since employees can still continue working in case of minor
illnesses.
4)
The company enjoys higher productivity since employees are more relaxed and comfortable
at home.
5)
No stoppage of work in case of riots or natural hazards like floods.
6)
Reduced overhead costs such as renting office space, electricity e.t.c. thus more profits to the
company.
Disdvantages of Teleworking to Company (Employer)
1) Management of the tasks and employers may be hard and time consuming.
2) Managers may feel they don’t have sufficient control over what the workers are doing during
working hours.
3) Employees may fail to meet deadlines which will lead to losses to the company.
4) Workers may not be available when the company tries contacting them.
Social and Economic Benefits of Teleworking
Apart from benefiting the employer and the employee, teleworking results into general benefits to the
society at large. These include;
 Reduced traffic congestion since less people travel to towns to work.
 Reduced total travel and consequent pollution in towns.
 Wider employment opportunities that reduces unemployment in the society
 Provides easy access to work for people with specific difficulties
 Teleworking saves costs both for employers and employees and these funds can then be invested in
projects that lead to economic regeneration in the society.
Social Life;
The internet has had a huge impact on the way in which people socialize.
 Social Interaction – Internet allows people to interact with any other connected person on the planet
through virtual environments.
 Cyber Bullying - the internet can be used to make communications aimed at to upset or embarrass
someone
 Physical Activity - Access to online goods and services people not have to leave the comfort of their
homes to use the services, this reduces need for physical activity as part of daily life which could have
negative effects on people's health and wellbeing.
Staying Safe Online
 Zip it - Always keep your personal information private and don’t share it with strangers by using
private settings on social networks. Use strong passwords and change them regularly.
 Block it - Always block offensive messages or friend requests from strangers on social networking
sites. Do not open suspicious attachments or links and use safe search filters to reduce the chances
of seeing age-inappropriate content.
 Flag it - Inform an adult if something online upsets you.
Digital Footprint
This is all the data that a user creates online which is recorded and stored. Is the impression that you leave
online which is shared or recorded either on archive sites or as backups.
You can minimize your digital footprint by: Closing old social media accounts and request all archived data to be deleted.
 Searching for your own name online and see what information about you is publicly available
 Ask website owners to remove old and irrelevant content about you.
 Read terms and conditions when creating online accounts since some still have rights over your data
even after closing your account.
Impacts of the Internet On Organizations
Positive Impacts
 Improved Communication
Organisations can communicate and interact with their customers and employees more easily
and in real-time using email, instant messaging and social media. They can provide up-to-date
information about the development, pricing and availability of their products and services.
Organisations can also publish live information online, allowing people to follow the
organisation's activities
 Access To Global Markets
The internet has made it easier for organisations to advertise and sell to customers in
countries around the world. Producers of digital content are now able to sell their
products online without having to create physical packaging and can avoid postage
charges. In addition, the internet has also ensured that manufacturers have easier access
to businesses that produce materials and parts and can communicate more easily with
them.
 Access To Global Workforce
Organisations can employ people in other countries. This means that the organisation can make
use of different skills and time zones who will work at different time to ensuring that the company
provides 24-hour services.
The organisation may also be able to reduce its costs because people in some countries will
accept lower wages than in other countries.
 How Information Is Managed And Used
Organisations can make use of big data to understand the behaviour of their
customers, improve the customer experience and make their processes more
efficient.
Data can be gathered from analysing social media posts, web browsing patterns,
ratings and current sales in order to predict w h a t w i l l h a p p e n i n
future
Negative Impacts
 Security Issues
The data stored by organisations is often private and valuable. If data is stored in a central
location, it can be physically secured by walls, locks, alarms and security guards. None of
these methods is totally safe, but they are all good ways of securing data.
However, as you have already seen, employees often work from home. Organisations use the
internet to provide their employees with access to their systems while working from home.
They do so using three methods:
1) allowing employees to transfer a copy of the organisation's data to home via email
2) providing remote access to the data stored in the organisation's building, such as by
using a VPN
3) Storing data on another company's servers and providing access to that data. Each of these
methods means that the data is more vulnerable to being accessed by an unauthorised userthan
it would be if it remained in a central location.
There are three main ways in which unauthorised users can gain access to systems.
•Authorised users reveal their login details, either intentionally or unintentionally, such
as by losing paper copies of their login details, saving their login details to a
computer that they lose, being pressured into telling someone their details or
having passwords which are easy to guess. Organisations have policies that help
employees to understand and manage these risks. Policies like these make
employees accountable for their actions, which means that they are more likely to
act responsibly.
• Unauthorised users intercept the data, either as it is transferred over
the internet from the organisation to the employee's computer or as it is transferred
within the employee's LAN after it has been transferred via the internet (WAN).
Organisations often use encryption to secure data when it is transferred using the
internet, which protects data even if it is intercepted.
•
Unauthorised users hack into the organisation's systems. To prevent access to their
systems from the internet, organisations use authentication, firewalls and intrusion
detection systems.
 Greater Competition
In the past, organisations usually competed with other organisations in their local area
or their own country. However, the use of the internet means that organisations must
now compete in a global marketplace. In some industries, there are more organisations
with which to compete. Large organisations can also become less attractive to
customers because they may be less flexible than small online businesses.
Some types of organisation and even whole industries have been put at risk due to
the way in which the internet has provided new channels for the trade and distribution
of goods and services. i e
o Music and film retailers have been threatened by the increased use of online
downloads and streaming ie Netflix.
o Newspaper publishers and television broadcasters have had to adapt because
individuals have a greater choice and more convenient access to news and
information services online.
o Postal services have been negatively affected by people's ability to send
messages and digital media instantly.
Impacts of the Internet on the Society
The Digital Divide
•
Digital Divide refers to the gap between people who have access to digital devices and the internet
and people who do not. It also relates to access to television, telephones and a wide range of digital
devices
Causes of Digital Divide
Economy and infrastructure: Countries with advanced economies can afford to invest in the
infrastructure required to provide access to networks and the internet. In countries with emerging and
developing economies, governments may prioritize other needs, such as food and healthcare, rather
than access to digital technologies .
• Politics: Governments that want to control access to information can either prevent or reduce access to
the internet for their citizens. Some governments do not allow people to visit certain websites or
content from other countries. Other governments have banned people from using satellite receivers so
that they cannot access television or radio broadcasts from countries with cultural influences they
disagree with.
• Religion: Some religions ban access to certain technologies. For example, Old Order Amish communities
in the United States of America do not use radio, television or the internet.
•Disability: If digital devices are not designed to be inclusive, people with disabilities can find accessing
technology more difficult and may have to rely on adaptations to be able to use ICT.
•
Geographic location : People may not be able to access online systems in remote locations. For example,
in rural areas or locations where wireless signals or cabling cannot reach, such as heavily forested and
mountainous areas.
• Difference in income : people who earn more have more money to invest in modern technologies as
opposed to the poor who may not afford to use modern technology.
• Technological advancements : countries with advanced technology like Japan have better access to
internet and other ICT facilities than those that are not.
• Age : the younger generation feels more comfortable with the new technology and are able to benefit
from it more than older people. Older people are less likely to have a computer and are less likely to be
interested in using Internet.
• Gender : Boys use computers and the Internet more than girls.
• Family structure : Families with children have more computers and Internet access than families
without.
• Education : Educated people are more likely to access and use modern technologies than those who are
not
• Ethnicity : Different ethnic groups have different attitudes to technology. Many deprived areas of large
cities have high numbers of people in differing ethnic groups. This may have an effect on wealth and
education.
• Motivation : People may not use computers because they are not interested or they may not see any
good reason to.
• Fear : Some people have a fear of using computers. These people are called 'technophobes'. Their fear is
usually due to poor ICT skills.
•
Impacts of Digital Divide
An individual with limited or no access to digital technologies will have the following: Less access to communication with other people.
 Will be isolated and reduced understanding of different cultures.
 Affects the ability to find bargains and good deals.
 Reduce people’s access to popular culture (entertainment).
 Reduce people’s employment opportunities.
Impacts of Unrestricted Access to Internet
Less restricted access to networks has had an impact on a number of elements of society like the media and
internet.
Positive Impacts
 Easy and faster distribution or broadcast of messages and information e.g. through the media &
social networking sites.
 Unlimited access to online content and services.
 Wide variety of online sources.
 May avoid censorship and biased reporting.
 Allows collaboration/ discussions with others.
 Helps to bridge the gap between the information rich and information poor.
 Encourages distribution of positive information
Negative Impacts
 Availability of information which might not be relevant, accurate or valid and biased.
 Too much information will be available hence difficult to extract key information.
 Fast distribution of wrong information over the internet poses a great problem to law enforcement
agencies like the police.
Operating Online
Online Communities
An Online community is a group of people with a shared common interest who communicate online.
Each type of online community has:
 A function - what it does for people who use it
 Features – what enable it to achieve its function
Different online communities provide different features that their members can use to interact with each
other. Features that provide the function of one type of community now could be used for other types of
community in the future, because the internet and its uses are always evolving.
Types of Online Communities
1) Social Networking Communities
2) Online Work Spaces
3) Online Gaming Communities
4) Virtual Learning Environments
5) User-generated Reference Sites
Social Networking Communities
Social networking is the practice of forming and joining groups in a society. This is something that humans
have been doing even before the invention of the computer. However, the internet has provided new ways
for us to form social networks.
Examples include;
Facebook, Baidu® and Twitter.
Function of Social Networking Communities
Online social network communities allow members to connect through shared interests or relationships.
These communities include professional networks such as Linkedln® and personal networks such as
Facebook.
These different types of network started out with separate functions. However, just like the convergence of
different types of digital device the features and use of different types of social network are starting to mix
together.
For example, some personal networks such as Facebook and Twitter are used by professionals and
businesses as well as for personal relationships.
Features of Social Networking Communities
Features of an online community refer to the settings or components found in that community to enable it
achieve its function.
Social networking communities are meant to connect members and enable them share information.
Features of Social Networking Communities
The following are features of a social networking online community;
 Profiles
 Friend, follow and connect
 Stream, wall and timeline
 Status updates and posts
 Groups, lists and circles
 Tags
 User suggestions
 Reactions, ratings, likes, upvotes and downvotes
 Share
 Comments and quotes
 Third-party integration
 Add content to posts
 Private or direct messages
 Notifications
 Analytics
Profile
This is a collection of user information provided by the user when creating an account with a social
networking community.
Profiles can be personalized by members and they can include:
 Biographical details
 An 'about you' or short description of the user
 Details about the user's work and education
 Travel history
 Family details
 Contact information
 Profile & background images, color schemes & designs.
Friend/Defriend, Follow and Connect
Different social networking communities have similar features that allow users to add someone to their
social network. These can be known by many different names such as friend, follow and connect.
Some communities allow their members to restrict other users' access to their full profile until the other
users request to add them to their network. Other communities allow totally unrestricted access.
Stream, wall and timeline
The development of the wall or timeline has changed how people communicate online, as it ensures that
information is brought straight to the user rather than making the user look for information.
Status updates and posts
Members of a social networking community can either send a message to other members in their network
or send it publicly to all members of the community.
Social networks are powerful marketing tools because they contain a huge amount of information that
people post about themselves. The owners of the social networking community can store this information
in a database and analyze it. They can then sell this information to advertisers, because this gives the
advertisers the ability to specifically target relevant sponsored posts to matched members. The ability to
match members to advertisements is called targeted marketing
Groups, lists and circles
Social networking communities usually allow members to create named groups, lists or circles of
members. Users' posts can then be made visible only to members of one or more of those groups. For
example, a member could use this to keep posts for family separate from posts for work. Organizations
can also use this so that smaller teams of people can communicate with
each other effectively without sending information to everyone in the entire organization.
Tags
Tags allow members to categorize the content that they create and post on social networking
communities. Other members can then search for content using the tags that were added to the content
when it was posted.
User suggestions
Social networking communities suggest other members that users might want to connect with. They often
do this by analyzing a user's interests and the interests of people within that user's social network, then
matches them to friends of existing connections.
Reactions, ratings, likes, upvotes/downvotes
Social networking communities have features that enable users to show their reactions to posts by other
people, such as liking them or finding them funny. These features also allow users to recommend posts to
other members of their community. Downvotes are used on some social networking communities to show
that users dislike a post.
Share
Share functionality allows members of a social networking community to repeat other members' posts to
the community. This makes the original posts available to more people. When a post is shared widely on
the internet and spreads far beyond its creator's original social network, people describe this as 'viral' or
'going viral'.
Comments and quotes
Social networking communities provide different ways for members to write comments about other
members' posts. This functionality allows members to have online conversations and to communicate with
each other
Third-party integration Many websites now include direct links to social networking sites so that people can easily share the
information provided on the third-party website.
Additional Features
Add content to posts - Allowing members to add content such as photographs, videos and URLs to their
posts means that members can share their experiences in different ways. This feature usually allows users
to preview the content before they post it.
Private or direct messages - Most social networking communities allow their members to send private
messages to each other, rather than having to post messages publicly.
Notifications - Notifications tell members about new activities within a social networking community.
They help keep members involved with the rest of the community.
Online Gaming Communities
These are online communities that enable users to play multiplayer games together over the internet.
Examples include;
PlayStation Network, Xbox Live, Steam©10 and Massively Multiplayer Online Role-playing Games
(MMORPGs).
Features of Online Gaming Communities
The features that support the function of Online Gaming Communities include;
 Links to social media
 User profiles
 Information on how to play the games
 Experience points that can be tracked and displayed on a user’s profile
 Discussion boards and forums to allow members discuss tactics
 Statuses to allow members see if a friend is online
 Notifications
Online Work Space
Online Work Spaces exist to enable members of the community to collaborate together for the purposes
of work.
Examples include;
Adobe® Connect, Slack®, Microsoft SharePoint® and WorkPlace by Facebook
Features of Online Work Space
The features that support the function of online gaming communities include:
 Cloud storage and web applications that allow members to work on documents through web
browsers
 Comments that can be left on documents for other users to see and reply to.
 Enabling documents to be edited at the same time by two or more members, which allows users to
develop the documents together.
 Messaging systems so that members can discuss the work.
 Shared calendars so users can see each other's diaries and arrange meetings
 Shared contact lists
 Chat rooms to allow discussion of work
 Systems for booking resources such as ICT equipment, meeting rooms and transport
 Virtual meeting spaces with the ability for members to:
 Give and watch presentations
 Speak to each other using VoIP
 Use video conferencing tools.
Virtual Learning Environments
These are websites that contain teaching and learning tools.
VLEs are used to allow students and teachers to use learning and assessment materials.
Examples include;
Pearson Active Teach, Google Classroom™ 12, Moodle™, Schoology® and Blackboard®.
Features of Virtual Learning Environments
The features that support the function of VLEs are very similar to those found in online work spaces.
In addition, many VLEs look like and work in a similar way to social networking communities, but they do
not aim to connect users with people outside their network.
Features of VLEs include:
 A wall or timeline that contains posts by teachers and students
 A notice board for announcements about the course
 The ability to share audio, video, web links or files
 Quizzes or multiple choice tests that are often graded automatically
 Tools for submitting assignments
 Communication tools, with posts usually moderated by the teacher:
 Forums for discussions
 Chat rooms
 Wikis
 Blogs
 Third-party integration, such as social networking features.
VLEs also have the following additional features.
 Log-in system: This is often linked to the school or college's information management systems so that
students are logged in automatically if they are already registered on their institution's network. This
is known as single sign on.
 Document editors: These allow teachers to create and edit documents that students can use and
sometimes collaborate on with their teachers.
 Gradebooks: These allow teachers and students to monitor progress through course materials &
assignments.
 Access statistics: These allow teachers to track how frequently students access and use the VLE's
facilities.
User-generated reference Sites
These are information websites created and maintained by communities of members.
These can be categorized as;
Wikis, Forums, Video-sharing & Photo-sharing Sites, Blogs/Vlogs
Wikis
These are website or database developed by multiple collaborating users, all of whom can add and edit
content.
Examples include;
the online encyclopaedia, Wikipedia, and the online music database, Discogs.
Features of Wikis
The function of a wiki is to allow members of the community to collaborate in order to build and edit web
pages.
The features that enable the function of wikis include:
 Member accounts, which allow users to track which edits have been made by which members of the
community
 An edit button, which takes editors to a text editor so that they can edit the content
 Structured language, which allows members to format web pages or add links to other content
 Search tools.
Forums
An online forum is a website or web page where users can post comments and information and reply to
other users' comments. Forums are also known as bulletin boards or message boards.
Examples include;
Yahoo!®, Google Groups™ 13, Stack Overflow®, Quora® and The Student Room®.
Features of Forums
Forums provide members of the community with online spaces for structured discussions. Posts on the
forum are arranged in topics or threads.
The features that enable the function of a forum include:
 Groups, allowing members in one group to have different levels of access or rights to members in
other groups
 Moderators, who are members who have the right to allow or block posts or members
 Administrators, who are members with the same privileges as moderators plus some additional
rights, such as being able to promote members to be moderators and demote moderators
 Posts, which are messages sent by members to the group
 Threads, which are topics for conversation, with replies usually arranged and sorted by date or topic
 Sticky notes or stickies, which are threads kept at the top of the list of threads to make them easily
accessible to members
 Ratings, which allow members of the community to rate other members' posts and enable members
to see how helpful or genuine the posts are
 Private or direct message functions, which allow members of the community to send private
messages to each other; sometimes these can also be seen by moderators or administrators.
Many forums also include a number of safety features
 Word or URL censoring: When posts are submitted to a forum, they are scanned (usually
automatically by software) for inappropriate words and URLs. If any are found, the post is rejected
automatically or sent to moderators to check.
 Ignore or block: These are safety features that mute members or stop them from being able to
access the forum.
 Rules and responsible or acceptable use policies: These tell members what they can and cannot do
on the forum. If members break the rules, then moderators or administrators can send them a
warning via private message or block them from the forum.
 Report or flag a user or post: This feature allows members to tell moderators if other members have
broken the rules of the forum.
Video-sharing & Photo-sharing Sites
These are sites that allow people to access and share content created and uploaded by members of the
community.
Examples include;
Vimeo®, Flickr®, 500px, Giphy® and YouTube®
Features of Video-sharing & Photo-sharing Sites
 The features that enable the function of video- and photo-sharing sites include:
 User accounts and profiles
 Content management systems, which allow users to add content to a page or to edit content on a
page
 Tags to categorize shared content • ratings, which allow users to rate shared videos and photographs
 Comments, which allow people to discuss the photographs and videos that have been shared
 Third-party integration such as social networking features, which allows users to share and react to
uploaded videos or photographs on social networking sites
Blogs and Vlogs
A blog is a website or web page that is updated regularly, often written like a diary or a series of articles. A
vlog is a video blog.
Examples include;
Weibo®, Wordpress®, Tumblr® and YouTube.
Blog (short for web log) a website or web page that is updated regularly, often written like a diary or a
series of articles
Vlog (short for video log) a video blog
Blogger someone who creates or maintains a blog
Function of Blogs and Vlogs
Blog and vlog communities allow people to create online diaries of events or articles. They are very similar
to wikis, but they usually contain additional features and more integration with social networking sites.
Individual blogs or vlogs are only called communities if two or more authors collaborate to create and
update them, or if they allow interaction between the blogger and their readers.
Features of Blogs and Vlogs
The features that enable the function of blogs and vlogs include:
 User accounts and profiles
 Text editors, which allow bloggers to write and edit their content online
 Upload tools for adding videos and photographs
 Tags
 Ratings
 Comments
 Third-party integration such as social networking features, which allows users to share and react to
the blog or vlog.
Social Bookmarking Sites
These are sites that allow users to categorize and share web documents and URLs so that other people can
access them. They exist to allow people to share web documents and URLs with each other.
Examples include;
Pinterest®, Digg®, Pocket™, reddit® and StumbleUpon®.
Features of Social Bookmarking Sites
The features that enable the function of social bookmarking sites include:
 Social networking features to connect users with each other
 Third-party integration such as social networking features, which allows users to share and react to
content on social bookmarking sites directly from websites using buttons
 Tags to organize and categorize URLs
 User accounts.
Issues Arising from Online Communities
The use of Online communities has been appreciated to a large extent. However, a few issues may arise.
These include;
 Anonymity Of Others And Misrepresentation
 Disclosure Of Personal Information Or Location
 Cyberbullying
Anonymity of Others & Misrepresentation
Anonymity is the state of being anonymous, i.e. other people do not know who you are or what your name
is.
Misrepresentation refers to pretending to be someone or something that you are not in the real world
during your interaction online.
Members of online communities can choose to stay anonymous online. Anonymity can protect users, but
it also means that some users can misrepresent themselves by pretending to be someone that they are
not.
Make sure you know who you are talking to online. If you get to know someone online, never arrange to
meet them in person on your own
Disclosure of Personal Information/Location
It can be dangerous to disclose too much personal information online. For example, people could use this
information for the purposes of grooming or to locate the person or their friends and family. In some
cases, location data can be given away, either on purpose or by accident, by uploading geotagged
photographs to photo-sharing sites.
Many online community apps for mobile devices enable users to include their location in their posts. This
information is provided by GPS data, or calculated from data provided by the user's Wi-Fi access point or
ISP data.
Cyberbullying
Cyberbullying is the term used to describe the use of the internet to send text or images in order to upset
or embarrass someone.
Implications of Digital Technologies
Digital technologies are incredibly powerful tools. Their implications and how they are used will determine
whether their use helps to build a better society.
• The use of digital technologies has changed the way in which people share and use information,
images, music and films.
• It has introduced new challenges relating to protecting the rights of individuals while also protecting
communities from harm. It forces us to rethink and question the concepts of ownership, privacy,
identity, censorship and control.
• It can provide new ways of improving our health and safety, but it can also put our health and safety
at risk.
• It also helps us understand and control our impact on the environment but also creates new ways in
which people can damage the environment.
Data Protection
Some countries have laws to ensure that, when data is stored about individuals, that data is protected.
One common law used in many countries is the Data Protection Act (DPA). This ensures that organizations;
• Get the individual's consent to collect, use or disclose personal data
• Collect, use or disclose personal data in an appropriate manner for the circumstances and must have
informed the individual of their purposes
• Collect, use or disclose personal data only for purposes that would be considered appropriate to a
reasonable person in the given circumstances.
Important Terms
•
•
•
•
Personal Data – is data relating to a living individual who can be identified from that data. E.g. a
school can store information about students.
Data Subject – the individual about whom the data is stored. E.g. students are the data subject
Data Controller – The individual or organization that is responsible to collect, store and use personal
data. E.g. the school is the data controller.
Data commissioner – this is the organization that ensures that all individuals or organizations that
collect personal data adhere to the Data Protection Act.
The Data Protection Act (DPA)
The Data Protection Act designed to protect personal data stored on computers or in an organized paper
filing system. It gives provisions on the protection, processing and movement of data.
DPA has 8 principles;
The Data Protection Act Principles
1.
2.
3.
4.
5.
6.
7.
8.
Personal data shall be processed fairly and lawfully
Personal data shall be obtained only for specified and lawful purposes
Personal data shall be adequate, relevant and not excessive.
Personal data shall be accurate and kept up to date.
Personal data shall not be kept for longer than is necessary.
Personal data shall be processed in accordance with the rights of data subjects (individuals).
Personal data shall be kept safe and secure.
Personal data shall not be transferred to a country or territory without adequate level of protection
The Rights of the Data Subjects (Owner of the Data)
Under the Data Protection Act, individuals whose data is stored by organizations have the right to:
1. access a copy of the information comprised of the data
2. object to data processing that is likely to cause or is causing damage or distress to the individual
3. Prevent processing for direct marketing, such as being sent newsletters or emails
4. Object to decisions that are taken by automated means
5. Have inaccurate personal data rectified, blocked, erased or destroyed in certain circumstances
6. be compensated for damages caused by a breach of the Act
Exceptions to the Rights
The Act provides a number of exceptions in which the personal data may be processed without the rights
of the data subject;
 Any processing for the purpose of safeguarding national security is exempt from all the data
protection principles and the data subject access rights
 Data processed for the prevention or detection of crime, the apprehension or prosecution of
offenders, or the assessment or collection of taxes are exempt from the data protection principles.
 Processing by an individual only for the purposes of that individual's personal, family or household
affairs.
 Processing may except data subject rights if revealing the data may damage or harm the subjects
health.
Copyright Legislation ©
Copyright is a legal power that provides the creator of an original work with the sole authority to use and
distribute it.
 When a user downloads original work such as software, books, music, images or videos, the work
that they download may be protected by copyright.
 Copyright owners can choose to distribute their works under licenses that users must pay for, such as
when buying a music track or an app from an online store. They can also choose to distribute their
works under free licenses such as open source or Creative Commons licenses, which allow the owner
to distribute their work without payment and say how their work can be used.
 Creative Commons licenses allow owners to distribute their work freely but still protect their rights
by specifying how their work can be used, shared and altered by other people
Exceptions to Copyright Legislation
When a customer pays for apps, books, music, images or videos, they pay for the right to use them, but
this does not usually also include the right to distribute them to others. However, exemption from
copyright applies in some situations. Some examples of are:
 Copies, such as copies of books or documents, made by libraries, educational establishments,
museums or archives
 Recordings of broadcasts for archive purposes
 Uses for the benefit of people with a disability
 For non-commercial research or private study
 When used in parody - an exaggerated imitation for the purpose of humor
Protecting Copyrighted work
In order to check that copyright law is not being broken, owners of digital works can protect their work by
using: Copy Protection and Digital Rights Management (DRM). These systems are designed to check that
the device on which the work is opened is allowed to open it. E.g. music files that are downloaded
using Apple iTunes®14 are often protected with DRM.
 Geoblocking - prevents some online users from accessing digital content. Also refers to limiting
access to internet content based on the user's geographical location. Also known as Geolocation
Rights Management (GRM)
Monitoring Individuals
Digital technologies can be used to monitor individuals. This can have both benefits and significant
drawbacks.
Digital technologies can be used to monitor individuals movements as well as individuals communication.
Monitoring Individual’s Movement
Individuals' movements can be monitored using many methods. E.g. include:
 CCTV (Closed circuit television) – this is a system of cameras placed in public buildings or in the street
that are used to help prevent crime and uses facial recognition software.
 Automatic number plate recognition (ANPR) - cameras used by law enforcement agencies such as the
police
 Monitoring the use of identification cards, travel cards, passports at borders and bank card
transactions
 Identifying devices on networks by their IP or MAC address
 Using GPS data shared by apps such as friend finder apps for mobile devices
 GPS trackers that can be attached to items of clothing such as belts
Benefits of monitoring individuals' movements include:
• Find people who are lost, especially young children
• Locate nearby friends in order to arrange to meet socially
• Identify people on networks
Drawbacks of monitoring individuals' movements include:
• Compromising people's privacy
• The expense of setting up, monitoring and maintaining systems
• The energy consumption of the systems and the effect on the environment
• Making people feel as though they are not trusted.
Monitoring Individual’s Communication
There are many ways in which individuals' communication can be monitored. For example,
• Parents can use parental control software to monitor their children's online activity and use of
applications.
• Text messages, emails, posts on social networking sites, comments on blogs and web histories can be
recorded.
Sustainability Issues
The use of digital technologies can negatively affect the environment. For example, it can use up natural
resources and contributes to long-term harm to the ecology of the planet.
The following table shows three ways in which the use of ICT can cause sustainability issues and lists some
of the ways in which the effects of these issues can be mitigated.
Sustainability Issues & Mitigating the Effects
Health and Safety Issues
It is important that you should know about the health and safety risks associated with digital technologies,
for both yourself and for others.
You also need to know what causes those risks and how to minimize them.
Good Posture when using a Computer
Risks to Safety Causes and Prevention
ARTIFICIAL INTELLIGENCE
 Artificial Intelligence (AI) is the ability of a computer program to make
decisions that would otherwise be made by humans.
 As we increase the number of decisions that technology makes for us in our
everyday lives, we reduce the control that we have over important
decisions that can have an impact on our health and safety.
 E.g. Artificial Intelligence (AI) is now used in self-driving cars and it can
make decisions about whether the car should apply the brakes if it is likely
to crash into the car ahead, or whether it should swerve to avoid another
vehicle.
 These cars can use sensors to detect whether the car is crossing a lane
divider in the road in order to prevent the car drifting into the wrong lane.
 AI can also read speed limit signs, adjusting the car's speed in order to
ensure that the car does not travel faster than the speed limit.
These are all useful tools. However, these AI systems do not have human
judgment and cannot apply common sense. Consider the following situations: What if a car needs to travel over the speed limit, perhaps to avoid a
hazard? Would AI software prevent the car from doing this if it was also
supposed to stay under the speed limit?
 What if a car had to swerve to avoid another vehicle, but in doing so veers
off the road and into a pedestrian? What would the computer decide to do
in that situation? Can we know what it decided to do? Can we hold it
responsible?
CHAPTER 10: ONLINE INFORMATION
INFORMATION SOURCES
Information is available from a wide range of sources. These can either be: Primary sources, which are those that you have created yourself, or
 Secondary sources, which are those that have been created by someone
else.
SEARCH ENGINES
 If you want to find information online and do not know the URLs of any
sites that contain that information, you can use a search engine. Search
engines compare the words entered by a user with words in a database of
web pages.
 They then show the user the results that are the closest match to their
original keywords.
 Search engines can be used in browsers, but they are also used by smart
personal assistants such as Amazon's Alexa® and Apple's Siri®14. These
personal assistants allow you to speak your search terms aloud and have
results returned through a speaker.
Examples of web-based search engines are:
• Bing
• Google
• Yahoo
KEYWORDS
• Keywords are the words or search terms that a user types into a search
engine in order to look for matching information. When entering keywords
into a search engine, only enter the important words that you think
websites will contain. Keep it simple and do not add too many keywords.
SEARCH TYPES
• Some search engines allow you to specify the type of information that you
are searching for, as shown in Figure 10.4.
SUGGESTED SITES AND AUTOFILL
Some search engines give results using autofill as soon as you start to type
keywords into it. Some browsers also allow you to choose a search engine so
that you can type keywords directly into the browser's address bar.
The suggested results often change as you continue to type more text, because
the additional terms allow the autofill software to narrow its search for more
relevant words or phrases. Similarly, other search engines suggest sites that
users might be interested in visiting. These suggested sites can be based on
popular searches made by other users or your own browsing history.
Autofill - the automatic suggestion of a completed Word or phrase that is
provided as the user types.
Browsing history - the URLs that an individual user has visited, which are
stored in a file
SEARCH SYNTAX
 Syntax is the rules that dictate how words and phrases are used in
languages, including computing languages. For example, you can use special
characters in searches.
This will make the search engine give you more specific results.
AND (+)
Adding + between words will return only results that match both words.
NOT (-)
Adding - before a word will return only results that do not include that word.
PHRASE MATCHING ("")
Placing speech marks around a group of words will return only results that
include the whole phrase with the words in that specific order
FITNESS FOR PURPOSE
When you use information from a primary or secondary source, you need to
decide whether it is suitable or good enough for the purpose for which you are
planning to use it.
COPYRIGHT
If you use information, you should ensure that you have permission to do so.
Some information will require you to state the owner or source of the
information if you choose to use it.
PLAGIARISM - The practice of taking someone else's work or ideas and passing them off as one's own
The internet has made information easily available to many people. However,
this means that it is becoming more common for people to copy and paste
information, sometimes without even
checking that it is suitable or true.
Sometimes, they may even claim that this information is their own. This is
known as plagiarism.
If you do this in your assignments for school, college or university, you will be
punished and your marks could be reduced or you could fail the assignment
completely.
One way to avoid plagiarism is to: Rewrite or paraphrase information. When you do this, it shows that you can
find information, understand its meaning and then express it in your own
words.
 State where the original information came from. If you found the
information online, include the URL, the author's name (if it is available)
and the date on which you found the information.
Disclosure of Personal Information/Location
It can be dangerous to disclose too much personal information online. For
example, people could use this information for the purposes of grooming or to
locate the person or their friends and family. In some cases, location data can
be given away, either on purpose or by accident, by uploading geotagged
photographs to photo-sharing sites.
Many online community apps for mobile devices enable users to include their
location in their posts. This information is provided by GPS data, or calculated
from data provided by the user's Wi-Fi access point or ISP data.
If this feature is activated, then any member of the community can find out
exactly where that person is. To reduce the risk, online safety organizations
advise individuals to think carefully about how much of their personal
information they want to make public, and not to post publicly any images
containing information about their location.
It is also recommended that users check and update their privacy settings
regularly, so that only people that they know in the real world can access their
personal information online. Finally, members of online communities should
report anyone who they think may be misrepresenting themselves or who is
acting in a way that puts members of the community at risk.
Cyberbullying
Cyberbullying is the term used to describe the use of the internet to send text
or images in order to upset or embarrass someone.
How to Stay Safe Online
To stay safe when using the internet, users should follow three main rules:
 Zip it
 Block it
 Flag it.