Unit 2:

Computer Technology in Action

WUC118/03
Computers in a Networked Society

© Wawasan Open University 2017

 Unit Objectives
By the end of this unit, you should be able to:
Differentiate between software and
hardware.
Describe the various types of input, output
and storage devices.
Explain systems software and application
software.
 Unit Objectives
By the end of this unit, you should be able to:
Discuss the various types of mobile
applications.
Describe the various types of computer
security and ways to protect computers.
Use spreadsheet and presentation
applications.
 Topics
1. Hardware and software: Types and
functions
2. System and application software
3. Developments in mobile technology
4. Computer security and reliability
Hardware and Software:
Types and Functions
Hardware Software

Definition A physical component of a A pool of instructions that

computer system that executes allows a user to connect with
instructions provided by software and a computer and permits the
enables users to interact with the computer to perform tasks
system
Types Input, processing, control, System software, programming
storage and output devices software and application software
Examples Monitor, keyboard, mouse, printer, MS Office, Adobe Acrobat, Internet
video card, scanner, CD-ROM drive, Explorer, QuickBooks and Windows
modem and router
Failure Hardware failure is irregular and does Software failure is systematic and
have cumulative failure at the last stage does not have a growing failure rate
Durability Hardware fatigues over time Software does not fatigue over
time, but errors are detected
in software as time passes
Input Devices
• The primary purpose of input devices is to
allow you to insert data and to give
commands to a computer.
• Data can be entered in various ways, such
as by clicking, keying in or scanning.
Input Devices
Keyboard Ergonomic keyboard

• The keyboard is the main input device for

keying-in data.
• every keyboard has 104 keys as the de
facto standard.

Flexible keyboard

Virtual laser keyboard

Input Devices
Trackball mouse
Footmouse
Mouse
• a handheld input device which is
Scroll mouse
used to control a cursor displayed on
the computer screen.
• The cursor can be used to select and
Touchpad
move icons on a Graphical User
Interface (GUI).
• It can also be used to select text,
TrackPoint
files and folders displayed on a mouse
computer screen.
Input Devices
Joystick
• allows the user to control an object in a computer
program
• E.g: a plane in a flight simulator.
Input Devices
Scanner
• When text is scanned into a computer, Optical
Character Recognition (OCR) technology can be
applied.
• OCR is the process of capturing an image of text
and then converting the image into data which a
computer recognises as text.
Output Devices
Monitor
• also referred to as Video Display Units (VDUs).
• They display video images to computer users.
They have electronic circuitry, a screen, buttons
to adjust screen settings and a casing to hold all
the other components.
• The first computer monitors applied Cathode Ray
Tube (CRT) technology.
Output Devices
Printer
• can retrieve stored data from a computer or other
devices and generate a hard-copy of the data.
• They are frequently used and can print text and
images.
• There are two types of printers:
– impact
– non-impact
Output Devices
Printer
• Impact printers function by making physical
contact with an ink ribbon before striking the
paper. E.g: daisy wheel, dot matrix and line
printers.
• Non-impact printers print without making contact
with the paper; they do not strike the paper,
quieter and more efficient than impact printers.
E.g: inkjet and laser printers.
Output Devices
Braille display
• an electronic device that permits a blind user to
“read” a document displayed on a computer
screen.
• computer transfers the text to the output device
and then converts it into Braille, “displaying” it by
raising rounded pins through a flat surface on the
device.
Output Devices
Speech generating device
• an electronic output device which is used to
assist individuals who have serious speech
impairments or other problems that result in
difficulty in communicating.
• This tool is useful for children who are suspected
of having speech deficiencies.
• SGDs vary in their design. Some SGDs allow
users to choose what to output from a touch
screen.
Storage Devices
• a backup tool and also hold your OS and
application programs.
• two categories:
– primary storage
– secondary storage.
Storage Devices
• Primary storage devices
– lower access times and faster performance because
they hold data for short periods while your computer is
processing data.
– E.g: RAM, cache memory.
• Secondary storage devices
– non-volatile devices which keep data until it is
removed or overwritten.
– two orders of magnitude cheaper than primary storage
devices.
– Eg:are HDDs and SD cards.
Storage Devices
• Magnetic storage devices
– available in multiple forms, such as floppy disk
drives, tape drives and hard drives.
– work on the principle of magnetic charge.
– use magnetic heads to write and read data to
and from a magnetisable medium.
Storage Devices
• Magnetic storage devices
– Hard Disk Drives (HDDs) are non-volatile
memory storage devices. They store data
permanently and allow computers to retrieve it
whenever needed.
– Solid State Drives (SSDs) have started to
replace HDDs because SSDs perform better.
SSDs deliver faster access times and lower
latency compared to HDDs. They are a type of
non-volatile memory.
Storage Devices
• Magnetic storage devices
– Floppy Disk Drives (FDDs) fall under the
category of magnetic storage devices. In
1971, the first FDD was introduced.
– It was an 8-inch disk drive.
– 5¼-inch FDDs were used in the first desktop
computers. They stored between 360 KB and
1.2 MB of data.
– replaced by 3½-inch FDDs that could store
between 360 KB and 1.44 MB of data.
Storage Devices
• Optical storage devices
– a standard storage device that uses lasers
and lights to read data from and write data to
optical storage media.
– It is also called an Optical Disk Drive (ODD).
– The most common types are Blu-ray disks,
Compact Disks (CDs) and Digital Versatile
Disks (DVDs).
Storage Devices
• Flash Memory devices
– does not require constant power to hold data
because it stores data in integrated circuit
memory chips, but it is slightly more expensive
than magnetic storage.
– It is now widely used in mobile phones, SSDs,
cameras and tablets.
Storage Devices
• Cloud Storage
– Storage space provided on remote or network
servers (these servers make up the “cloud”).
– data can be downloaded or accessed through
the Internet.
– E.g: Amazon Drive, Oracle Public Cloud,
Microsoft Azure and OneDrive, Dropbox and
Google Drive.
Inside the System Unit
• Motherboard
Inside the System Unit
• Central Processing Unit (CPU)
– complicated electronic circuitry inside a computer
which carries out program instructions
– obtains data from input devices and storage
devices, processes the data, and then outputs the
results via output devices.
– It consists of a Control Unit (CU) and an Arithmetic
Logic Unit (ALU).
– CPU is the processor or microprocessor in a
computer.
Inside the System Unit
• Central Processing Unit (CPU)
– its primary role is to manage the operations of
hardware devices and to execute the instructions
given by software programs.
– Advanced Micro Devices (AMD) and Intel are the
market leaders.
Inside the System Unit
• Control Unit (CU)
– circuitry supervises a computer system’s
operations in carrying out program
instructions.
– acts as an orchestra conductor inside a
computer system; it commands the other
system elements to perform program
instructions.
– essential for the CU to interact with the ALU
and memory.
Inside the System Unit
• Arithmetic Logic Unit (ALU)
– The ALU carries out four kinds of
mathematical operations: addition, subtraction,
multiplication and division.
– The logic part of the ALU assesses logic
operations (e.g., greater than, equal to or less
than).
– ALU is built into the CPU and is able to hold
data that is currently being processed in
storage locations called registers.
Inside the System Unit
Inside the System Unit
• CPU operations
Inside the System Unit
• Memory
– Semiconductor memory
– RAM
– RAM modules
– ROM
– Flash memory
– Cache memory
Inside the System Unit
• Buses, ports and connectors
– Industry Standard Architecture (ISA)
– Peripheral Component Interconnect
(PCI)
– Accelerated Graphics Port (AGP)
– Universal Serial Bus (USB)
– FireWire/IEEE 1394
– PC Card
Inside the System Unit
• Expansion slots and cards
Inside the System Unit
Inside the System Unit
• Dedicated expansion ports
– Small Computer System Interface (SCSI)
– IEEE 1394 (FireWire)
– Musical Instrument Digital Interface (MIDI)
– Serial port
– Parallel port
– USB port
Data representation
Data
representation
• Binary Vs
decimal
number
system
Data representation
• Bits and bytes
– A bit (binary digit) is the smallest unit of
data in computing. Values: 0 or 1.
– A byte is made up of eight bits. It is used
to represent one alphanumeric character.
– Half a byte is called a nibble.
– Every character in the sentence “I love
WOU” is represented by one byte of data.
Data representation
• Character codes
– Extended Binary Coded Decimal
Interchange Code (EBCDIC)
– American Standard Code for Information
Interchange (ASCII)
– Extended ASCII
– Unicode
System software
• maintains and controls the operations of a
computer and its peripherals.
• Operating System (OS) is part of system
software.
• E.g: Microsoft Windows and system
utilities such as antivirus programs.
System software
• Components of an OS
– Kernel
– Shell
– File system
System software
• Functions of an OS
– Starting the computer
– Managing applications
– Managing memory
– Handling messages from input and
output devices
– Providing a user interface
System software
• OS utilities
System
software
• OS utilities
System software
• Categories of OS
Application software: Tools
for productivity
• Productivity programs
Application software: Tools
for productivity
• Productivity programs
Application software: Tools
for productivity
• Media and graphics software
– enable users to do professional desktop
publishing, multimedia authoring, drawing,
painting, animation, image editing, 3D rendering,
computer-aided design, and audio and video
editing.
– A codec or compression/decompression program
is a special computer program which reduces the
size of computer files. It reduces file transfer time
over the Internet and the required storage space.
Application software: Tools
for productivity
• Media and graphics software
– enable users to do professional desktop
publishing, multimedia authoring, drawing,
painting, animation, image editing, 3D
rendering, computer-aided design, and audio
and video editing.
– Codec is a special computer program which
reduces the size of computer files. It reduces
file transfer time over the Internet and the
required storage space.
Application software: Tools
for productivity
• Media and graphics software
– Two types of compression: Lossless & Lossy
– E.g:
• Microsoft Windows Media Player
• Desktop publishing programs
• Painting or drawing programs
• Image editors
• Animation programs
• Three-dimensional (3D) rendering programs
• Multimedia authoring systems
• Audio software
• Video editors
Application software: Tools
for productivity
• Internet-based software
– Web-hosted software technology allows us to
share files and collaborate using applications
such as Windows Live and Google Docs.
– It also helps us to avoid file incompatibility.
Application software: Tools
for productivity
• Home and educational programs
– There is a variety of home and educational
programs available such as personal finance
and tax software, interior design and
landscaping software, digital reference
software, and computer games.
Application software: Tools
for productivity
• Tailor-made applications
– specially designed for users based on their
specific needs.
– often cost more than general-purpose
applications because of their development
costs.
– Made based on the explicit requirements of
an individual or a business.
Developments
in Mobile
Technology
Developments in Mobile
Technology
• Types of mobile applications
– native app
– web app
– hybrid app
Computer Security and
Reliability
• Goals of computer security:
– Integrity
– Confidentiality
– Availability
Computer Security and
Reliability
• Main concepts in computer security
– Passive attacks acquire or exploit information
from a computer system without affecting
system resources.
– Active attacks modify or create false data
streams. Four types: masquerade, replay,
modification of messages,denial of service.
– A computer security risk is any event that
leads to loss of data or damage to computer
software, hardware or processing capability.
Computer Security and
Reliability
• Main concepts in computer security
– A cracker is someone with extensive computer
knowledge who accesses a computer or
network illegally to wipe out data, steal
information or perform other malicious actions.
– A cyber terrorist conducts acts of terror for a
political cause by using the Internet or networks.
– A rootkit is a program which is concealed in a
computer and allows someone to take control of
the computer from a remote location.
Computer Security and
Reliability
• Main concepts in computer security
– A cracker is someone with extensive computer
knowledge who accesses a computer or
network illegally to wipe out data, steal
information or perform other malicious actions.
– A cyber terrorist conducts acts of terror for a
political cause by using the Internet or networks.
– A rootkit is a program which is concealed in a
computer and allows someone to take control of
the computer from a remote location.
Computer Security and
Reliability
• Three types of computer security:
– Network security
– Software security
– Physical security
Computer Security and
Reliability
• Types of computer hackers:
– White hat hacker
– Black hat hacker
– Gray hat hacker
Computer Security and
Reliability
• Types of computer attacks:
– Denial-of-Service (DoS) attack
– Smurf attack
– Man-in-the-middle attack
– Packet sniffing
– DNS hijacking
– Phishing
– SQL injection attack
– Dictionary attack
Computer Security and
Reliability
• Types of computer viruses :
– Creeper virus
– Boot sector virus
– Virus hoax
– Polymorphic virus
– Cluster virus
– Stealth virus
Computer Security and
Reliability
• Methods to protect computers
– Get the latest anti-virus software and update it
frequently.
– Download files only from trusted sites. Do not
open any downloads from unknown sources.
– Perform a full backup of your computer
system regularly.
– Install a host-based and personal firewall
software program which analyses and controls
incoming and outgoing network packets.
Computer Security and
Reliability
• Methods to protect computers
– Always perform a virus scan when a new
peripheral device is connected to your
computer.
– Use disk encryption to encrypt your disks. Use
Public Key Infrastructure (PKI).
– Conceal data within other data by using a
steganography program.
– Use passwords and biometrics to prevent
unauthorised access to your computer.
Summary of Unit 2
• Hardware and software: Types and functions
– Comparison of hardware and software
– Input, output and storage
– Inside the system unit
• System and application software
– System software
– Application software: Tools for productivity
Summary of Unit 2
• Developments in mobile technology
– The evolution of mobile phones
– Types of mobile applications
• Computer security and reliability
– Computer security concepts
– Types of security and hackers
– Various types of computer attacks
– Methods to protect computers