ENGR 10005 Introduction to Cybersecurity
Midterm Review
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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Introduction to Computer Technology
- An Overview of the Computer Technology
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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What Is a Computer and What Does It Do?
• A computer is a programmable, electronic device that accepts data, performs
operations on that data, and stores the data
• Its instructions, called programs, determine the tasks the computer will perform
• Basic operations (the IPOS cycle)
Input: Entering data into the computer
Processing: Performing operations on
the data
Output: Presenting the results
Storage: Saving data, programs, or
output for future use
Communications: Sending or receiving
data
• FIGURE : The information processing cycle.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data versus Information
• Data is raw, unorganized facts
• Can be in the form of text, graphics, audio, or video
• Information is data that has been processed into a meaningful form
• Information processing is the conversion of data into information
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Computers Then and Now: First and Second
Generation Computers
• First-generation computers (1946-1957)
• Enormous and powered by vacuum tubes
• Used a great deal of electricity and generated a lot of heat
• ENIAC and UNIVAC
• Second-generation computers (1958-1963)
• Used transistors
• Computers were smaller, more powerful, cheaper, more
energy-efficient, and more reliable
• Punch cards and magnetic tape were used for input
• Punch cards and paper were used for output
• Magnetic tape was used for storage
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Computers Then and Now: Third and Fourth
Generation Computers
• Third-generation computers (approximately 1964–1970)
• Used integrated circuits (ICs), which consist of transistors and
electronic circuits on a single tiny silicon chip
• Keyboards were used for input; monitors for output
• Hard drives were used for storage
• Fourth-generation computers (approximately 1971–present)
• Use microprocessors, which contain the core processing of an entire
computer on a single chip
• Keyboards and mice are used for input; monitors and printers for
output; hard drives, flash memory media, and optical discs for storage
• Networks and the Internet were developed
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Computers Then and Now: Fifth Generation
Computers
• Fifth-generation (now and the future)
• Most commonly defined as being based on artificial intelligence (AI)
• Some aspects like voice and touch input are used today
• Future computers may be different, such as:
• Optical computers
• Tiny computers that utilize nanotechnology
• General-purpose computers built into everyday devices
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Computer Networks and the Internet
• A computer network is a collection of
hardware and other devices that are
connected together
• Users can share hardware, software, and data
• Users can communicate with each other
• Most computers and mobile devices today
connect to a computer network
• Examples include small and large business
networks, school networks, home networks,
public wireless networks, and mobile telephone
networks
• FIGURE: Example of a Computer Network.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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What Are the Internet and the World Wide Web?
• The Internet is the largest/most well-known computer network in the world
• Individuals connect using an Internet service provider (ISP)
• ISPs connect to regional networks, which connect to backbone networks, which connect
to form the Internet
• The World Wide Web (Web) is one resource (a vast collection of Web pages)
available through the Internet
• Web pages typically contain hyperlinks
• Web sites contain Web pages stored on Web servers
• Web pages are viewed using a Web browser (Edge, Internet Explorer (IE), Chrome, Safari,
Firefox, Opera, etc.)
• Web pages offer a wide variety of information and uses
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Accessing a Network or the Internet
• Need a network adapter to connect
• Many networks require a username and password
• Internet connections can be:
• Direct (always-on) connections
• Dial-up connections
• Internet addresses access resources on the Internet
• The most common types of Internet addresses:
• IP addresses and domain names (to identify computers)
• Uniform Resource Locator (URL) (to identifies Web pages)
• E-mail addresses (username) (to identifies person)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Introduction to Computer Technology
- The System Unit, Processing, and Memory
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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Inside a Desktop System Unit
• FIGURE: Inside a desktop system unit.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Processing Speed
• Processing speed can be measured by the CPU’s clock speed
• Rated in megahertz (MHz) or gigahertz (GHz)
• Higher CPU clock speed = more instructions processed per second
• E.g. Core i7 3.2GHz is faster than Core i7 2.66GHz
• Alternate measure of processing speed is the number of instructions a CPU can
process per second
• Megaflops (millions), gigaflops (billions), teraflops (trillions)
• Benchmark tests can be used to evaluate overall processing speed
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Word Size and Cache Memory
• A computer word is the amount of data that a CPU can manipulate at one time
• In the past, CPUs used 32-bit words (referred to as 32-bit processors); today, most CP
Us are 64-bit processors
• Cache memory is a special group of very fast circuitry usually built into the CPU
(internal cache memory)
• More cache memory typically means faster processing
• Cache memory level numbers indicate the order in which the various levels of cache
are accessed by the CPU
• Level 1 is fastest, then Level 2, then Level 3
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Bus Width, Bus Speed, and Bandwidth
• A bus is an electronic path over which data can travel
• Found inside the CPU and on the motherboard
• Bus width is the number of wires in the bus over which data can travel
• A wider bus allows more data to be transferred at one time
• Bus width and bus speed together determine the bus’s bandwidth (the amount of
data that can be transferred via the bus in a given time period)
• The amount of data actual transferred under real-life conditions is called
throughput
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Memory
• Memory refers to chip-based storage, or locations that a computer uses to store
data on a temporary basis
• Volatile memory (content is erased when the device is shut off)
• Non-volatile memory (content is retained when the device is shut off)
• Random access memory (RAM) is the computer’s main memory or system
memory
• Stores essential parts of operating system, programs, and data the computer is
currently using
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Inside a CPU Core
• FIGURE:
Inside a
CPU
core.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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The Machine Cycle
• FIGURE: A machine cycle. A machine
cycle is typically accomplished in four
steps.
• A machine cycle occurs whenever the
CPU processes a single piece of
microcode
• It consists of four operations:
• Fetch
• Decode
• Execute
• Store
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Introduction to Computer Technology
- Storage
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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Storage System Characteristics
• A storage system consists of a storage medium and a storage device
• The storage medium is the hardware where data is stored
• DVD disc, flash memory card, etc.
• The storage device is the hardware into which the storage medium is inserted
• DVD drive, flash memory card reader, etc.
• Can be internal, external, or remote
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Random versus Sequential Access
• Random versus sequential access
• Random access (direct access) allows data to be retrieved from any location on the
storage medium
• Virtually all storage devices use random access
• Sequential access means that retrieval of data can occur only in the order in which it was
physically stored on the storage medium; for example, a magnetic tape drive
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Magnetic Hard Drives (1 of 2)
• A magnetic hard drive or hard
disk drive (HDD) contains
particles on the metal disks
inside the drive that are
magnetized to represent the
data’s 0s and 1s
• FIGURE: Storing data on magnetic disks.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Magnetic Hard Drives (2 of 2)
• One or more metal hard
disks are permanently
sealed inside the drive
along with an access
mechanism and
read/write heads
• FIGURE: Magnetic hard drives.
• Source: Hitachi Global Storage Technologies; Seagate Technology LLC
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Hard Disk Organization
FIGURE: Magnetic hard
disks are organized into
tracks, sectors, clusters,
and cylinders.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Solid-State Drives (SSDs)
• A solid-state drive (SSD)
uses flash memory
technology to store data
• FIGURE: Solid-state drives (SSDs). Contain
only flash memory.
• Uses less power and has no
moving parts
• Much faster than magnetic
hard drives, but more
expensive
• The norm for netbooks,
mobile devices, and other
portable devices
• Source: Transcend Information USA
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Solid-State Hybrid Drives (SSHDs)
• A solid-state hybrid drive (SSHD) or
hybrid drive uses a combination of
magnetic disks and flash memory
chips
• FIGURE: Solid-state hybrid drives (SSHDs). Contain
both magnetic hard disks and flash memory.
• The data that is most directly
associated with performance is stored
in the flash memory
• Nearly as fast as solid-state drives (SS
Ds)
• Slightly more expensive than
magnetic hard disk drives (HDDs)
• Source: Seagate Technology LLC
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Optical Discs
• Optical discs are thin circular plastic
discs
• Are read from and written to using laser
beams
• Are commonly used for software
delivery
• Divided into sectors like magnetic discs
but use a single spiral track (groove)
• Have a relatively large capacity and are
durable
• Used for backup purposes and for
storing and transporting music, photos,
video, etc.
FIGURE: How recorded optical discs work.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Read-Only Optical Discs: CD-ROM, DVD-ROM, and
BD-ROM Discs
• CD-ROM, DVD-ROM, and BD-ROM discs are read-only
• Pits are permanent
• CD-ROM and DVD-ROM discs come prerecorded with software, music, movies, etc.
• BD-ROM discs come prerecorded with movies
• Ultra HD Blu-ray discs can be used for 4K movies
• Additional proprietary read-only discs
• Gaming systems like Wii, Xbox, PlayStation, etc.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Recordable Optical Discs: CD-R, DVD-R, DVD+R,
and BD-R Discs
• CD-R, DVD-R, DVD+R, and BD-R discs can be written to, but cannot be erased and
reused
• Pits are created in the disc when the disc is recorded
• Most discs have a recording layer containing organic light-sensitive dye between disc’s
plastic and reflective layers
• BD-R discs use inorganic material instead
• DVD-R DL and DVD+R DL are dual-layer discs
• BD-R DL discs are dual-layer discs; BD-R XL use 3 or 4 layers
• Used for backing up files, sending large files to others, and storing multimedia files
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Rewritable Optical Discs: CD-RW, DVD-RW, DVD+RW,
and BD-RE Discs
• CD-RW, DVD-RW, DVD+RW, and BD-RE discs can be written to, erased, and
overwritten just like magnetic hard disks
• Uses phase change technology
• Heating and cooling process is used to change the reflectivity of the disc
• The capacities are the same as their read-only and recordable counterparts
• Appropriate for transferring large files from one computer to another or otherwise
temporarily storing data (disc can be reused)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Flash Memory Storage Systems- Embedded
Flash Memory
• Source: Samsung Electronics Co., Ltd
• Source: SanDisk Corporation
• This tablet contains 64 GB of
embedded flash memory.
• An embedded flash memory chip.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Other Types of Storage Systems
• Remote storage refers to using a storage device that is not connected directly to the
user’s computer
• Network storage: Using a storage device via a local network
• Cloud storage (online storage) is accessed via the Internet
• A smart card is a credit card-sized piece of plastic that contains some computer
circuitry (processor, memory, and storage)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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RAID
• RAID (redundant arrays of independent discs) is a method of storing data on two or
more hard drives that work together to record redundant copies
• Used to protect critical data on large storage systems
• Helps to increase fault tolerance
• Different levels of RAID:
• RAID 0 = disk striping (spread files over two or more hard drives)
• RAID 1 = disk mirroring (duplicate copy)
• Other levels use a combination or striping and mirror
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Two Primary RAID Techniques
• FIGURE: RAID. Two primary RAID techniques are striping and mirroring.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Introduction to Computer Technology
- Operating Systems
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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The Operating System
• A computer’s operating system is
a collection of programs that
manage and coordinate the
activities taking place within a
computer
• FIGURE: The intermediary role of the
operating system.
• Acts as an intermediary between
the user and the computer and
between the application programs
and system hardware
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Processing Techniques for Increased Efficiency
• Multitasking refers to the ability of an operating system to have more than one program
(task) open at one time
• CPU rotates between tasks
• Multithreading enables the computer to rotate between multiple threads so that
processing is completed faster and more efficiently
• CPU rotates between threads
• Multiprocessing: Each CPU or core typically works on a different job
• Used with computers and devices that have multi-core CPUs and/or multiple CPUs
• Parallel processing: The CPUs or cores typically work together to complete one job more
quickly
• Used most often with supercomputers
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Sequential versus Simultaneous Processing
• FIGURE: Sequential versus simultaneous processing.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Memory Management
• Memory management optimizes the use of main memory (RAM)
• Helps speed up processing
• Virtual memory is a memory-management technique that uses hard drive space as
additional RAM
• Virtual memory is slower than just using RAM
E.g. 2GB RAM + 2GB virtual memory runs slower than 4GB RAM
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Graphical versus Command Line Interface
• A graphical user interface (GU
I) has icons, buttons, and
other objects that the user
selects to issue commands
• Used by most operating
systems
• FIGURE:
Graphical
user versus
command
line
interfaces.
• A command line interface
requires the user to input
text-based commands using
the keyboard
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Operating Systems for Personal Computers and
Servers
•
•
•
•
•
DOS (Disk Operating System)
Windows
OS X
UNIX
Linux
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Disk Operating System (DOS)
• DOS (Disk Operating System)
• Dominant operating system in the 1980s
and early 1990s
• DOS traditionally used a command-line
interface
• PC-DOS
• Created originally for IBM microcomputers
• MS-DOS
• Created for use with IBM-compatible
computers
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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OS X
• OS X is the proprietary operating system for computers made by Apple
Corporation
• Based on the UNIX operating system
UNIX
• UNIX is an operating system developed in the late 1960s for midrange servers
• More expensive, requires high level of technical knowledge; harder to install, maintain,
and upgrade
• “UNIX” initially referred to the original UNIX operating system, now refers to a group of
similar operating systems based on UNIX
• Many UNIX flavors are not compatible with each other
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Linux
• Linux resembles UNIX but was developed independently by Linus Torvalds in 1991
• Open-source software; has been collaboratively modified by volunteer programmers all
over the world
• Originally used a command line interface, most recent versions use a GUI
• Strong support from mainstream companies, such as IBM, NVIDIA, HP, Dell, and Novell
• Reasons to switch to Linux
• Cost
• More control over the computer
• Faster
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Linux Desktop
• FIGURE: Linux. This
version is Ubuntu, one of
the most widely-used
Linux operating systems.
•
Source: Canonical Ltd.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Chrome OS
• Chrome OS is the first cloud operating system
• Is essentially the Chrome Web browser redesigned to run a computer
• Replaces traditional desktop operating systems
• Designed for devices that are used entirely online
• Currently only available preinstalled on Chrome devices
• Chromebooks
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Operating Systems for Mobile Devices
• Mobile versions of personal operating systems (such as Windows or Linux)
• Android and Apple iOS
• BlackBerry OS and BlackBerry PlayBook OS
• Designed for BlackBerry devices
• Additional Linux-based mobile operating systems besides Android and iOS
• Ubuntu
• webOS
• Firefox OS
• Tizen
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Introduction to Computer Technology
- Information Systems and System Development
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
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What Is an Information System?
• A system is a collection of elements and
procedures that interact to accomplish a
goal
• An information System (IS) is a system used
to generate the information needed to
support the users in an organization
• A digital ecosystem is the collection of
people, products, services, and business
processes related to a digital element
• Apple digital ecosystem = Apple hardware,
software, and online services
FIGURE: Components of an information system.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Types of Information Systems
• While some information systems are unique, most fall into these six basic categories
• FIGURE: Types of Information Systems.
TYPE OF SYSTEM
DESCRIPTION
Office and user productivity systems
Facilitate communications and enhance productivity in office tasks
Transaction processing systems
Process and record business transactions
Decision making support systems
Provide needed information to decision makers
Integrated enterprise systems
Integrate activities throughout an entire enterprise
Design and manufacturing systems
Help with the design and/or manufacturing of products
Artificial intelligence systems
Perform actions based on characteristics of human intelligence
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Outsourcing
• Outsourcing involves hiring outside vendors to perform specific business tasks
• Offshoring
• Outsourcing to another country
• Nearshoring
• Outsourcing to nearby countries
• Homesourcing (homeshoring)
• Outsourcing to home-based workers
• Crowdsourcing
• Outsourcing a task to a large, undefined group of people via the Web
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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Outsourcing: Advantages and Disadvantages
• Advantages
• Lower costs and staffing flexibility
• Socially responsible outsourcing
• Disadvantages
• Communication problems and cultural differences
• Quality control and security
• Captive offshoring
• U.S. companies own facilities in other countries and hire employees in that country
• Gives company more control over employees and procedures than with conventional
outsourcing
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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The System Development Life Cycle (SDLC)
• The system development life cycle (SDLC) refers to the development of a system
from the time it is first studied until the time it is updated or replaced
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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SDLC (system)
PDLC (program)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
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System Conversion
• Direct conversion
• Old system is deactivated and new system is
immediately implemented
• Parallel conversion
• Both systems are operated simultaneously until it
is determined that the new system works properly
• Phased conversion
• System is implemented by module
• Pilot conversion
• New system used at just one location within the
organization
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
SDLC summary
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Introduction to Computer Technology
- Program Development and Languages
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Approaches to Program Design and
Development
• Procedural programming separates a program into small modules that are called
by the main program or another module when needed
• Allows each procedure to be performed as many times as needed; multiple copies of
code not needed
• Prior to procedural programming, programs were one large set of instructions (used
GOTO statements)
• Structured programming goes even further, breaking the program into small
modules and prohibiting GOTO
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Examples of Structured Programming
Modules
• FIGURE: Structured programming. A structured program is divided into individual modules; each
module represents a very specific processing task.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Object-Oriented Programming (OOP)
• Object-oriented programming (OOP) consist of a
collection of objects that contain data and methods
to be used with that data
• Class: A group of objects that share some common
properties
• Attributes: Data that describes the object
• Methods: Perform actions on an object
• Can be used with different types of objects
• Instance: An individual object in a class
• Inherits the attributes and methods of the class
• The values of attributes may vary from instance to
instance
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Aspect-Oriented Programming and Adaptive/Agile
Software Development
• Aspect-oriented programming (AOP) separates functions so program components
can be developed and modified individually from one another
• The components can be easily reused
• Adaptive software development adapts programs as they are being written
• Typically iterative and/or incremental development
• Agile software development (ASD) can create software quickly
• Focuses on building small functional program pieces as the project progresses
• Emphasizes teams of people working closely together (programmers, managers, business
experts, customers, and so forth)
• Some mobile developers are using continuous mobile innovation
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
The Program Development Life Cycle (PDLC)
• Program development (application
software development) is the process
of creating application programs
• Program development life cycle (PDLC)
includes the five phases of program
development
• Typically takes place during the system
acquisition phase of the SDLC
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Program Design Tools
• FIGURE: A flowchart example.
• FIGURE: Wireframes.
• FIGURE: Pseudocode.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Languages Used For Application Development
• A programming language is a set of rules, words, symbols, and codes used to
write computer programs
• Markup languages are most often used to create Web pages and Web
applications
• Use markup tags to identify elements and their properties
• Scripting languages are interpreted instead of compiled, so they are executed one
command at a time and at the time they are run
• Most often used to add dynamic content
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Low-Level Programming Languages
• Low-level languages (earliest programming languages)
• Machine language
• Written at a very low level, just using 1s and 0s
• First generation of programming languages
• They are the only programs without being translated.
• Assembly language
• Uses names and other symbols to replace some of the 1s and 0s in machine language
• Second generation of programming languages
• Programs take longer to write and maintain
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
High-Level Programming Languages
• High-level languages: Closer to natural languages
• Machine-independent
• Most are 3GLs and can be:
• Procedural languages (Fortran, BASIC, COBOL, C, etc.)
• Object-oriented languages (C++, C#, Python, Java, etc.)
• Can be visual programming environments (VPEs), which allow programmers to create
the interface graphically
• Can be visual programming languages which create programs entirely using graphical
elements
• Scratch
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Fourth-Generation Languages (4GLs)
• Fourth-generation languages (4GLs) (very-high-level languages)
• Even closer to natural languages and easier to work with than high-level languages
• Declarative rather than procedural
• You tell the computer what to do and it figures out how to do it
• Can result in less efficient code when compiled
• Commonly used to access databases
• Structured query language (SQL)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Introduction to Computer Technology
- Databases and Database Management
•
•
•
•
•
What a database is; individuals; and the software
Database concepts and vocabulary
Database classifications and models
How relational databases created and used
How databases are used on the Web
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All
Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Components of a Database
• A database typically consists of interrelated tables that contain:
• Fields (columns)
• Single category of data to be stored in a database (name, telephone number, etc.)
• Records (rows)
• Collection of related fields in a database (all the fields for one customer, for example)
• Relational database is most widely used today.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Primary Key
• A primary key is a field that uniquely identifies the records in a table
• Used in a relational database to relate that table to other tables
• FIGURE: Primary key fields. A
primary key field must contain
unique data so it can be used to
identify each record in the
table.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Individuals Involved with a Database Management
System
• Database designers design the database
• also called data architects, database engineers, and database analysts
• Database developers create the database and get it ready for data entry
• sett up database structure and create UI.
• Database programmers write the programs needed to access the database or tie
the database to other programs
• Database administrators are responsible for managing the databases within an
organization
• maintenance, backups, and security
• Users are individuals who enter data, update data, and retrieve information from
the database
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Advantages and Disadvantages of the DBMS
Approach
• Advantages
• Low level of redundancy
• Faster response time
• Lower storage requirements
• Easier to secure
• Increased data accuracy
• Disadvantages
• Increased vulnerability
• Security and backup procedures extremely important
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Entity Relationships
• One to one (1:1) entity relationships
• One entity is related to only one other entity of a particular type
• Not a common type of relationship
• One to many (O:M) entity relationship
• Most common type of relationship
• One entity can be related to more than one other entity
• Many to many (M:M) entity relationships
• One entity can be related to more than one other entity, and those entities can be
related to multiple entities of the same type as the original entity
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Integrity
• Data integrity refers to the accuracy of data
• Quality of data entered determines the quality of generated information
• Data validation refers to the process of ensuring that data entered into the database is valid
• Ensures entered data matches the specified data type, format, and allowable value for each field
• Can include record validation rules (checking the value of a field with the value of another field to
ensure validity)
• If data is invalid, an error message is usually displayed
• Can be enforced on a per transaction basis so that the entire transaction will fail if one part is
invalid
• Database locking prevents two individuals from changing the same data at the same time
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Security
• Data security protects data against destruction and misuse (both intentional and
accidental)
• Protects against unauthorized access to and unauthorized use of a database and data
loss
• Firewalls, access controls, access privileges, etc.
• Database activity monitoring programs can be used to detect possible intrusions and
risks
• Database encryption should be used
• Strict backup and disaster-recovery procedures can protect against data loss due to
database failure, accidental deletions, disasters, etc.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Privacy
• Data privacy addresses protecting the privacy of personal data stored in databases
• Many states require businesses to notify customers when their personal data has been
compromised
• Data breaches can be costly
• One estimate is $200 per breached record
• To protect the privacy of data, businesses should:
• Make sure all data they are collecting and storing is necessary
• Make sure they use adequate security measures
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Client-Server Database Systems
• A client-server database system has both clients (front end) and at least one
database server (back end)
• FIGURE: Client-server
database systems.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
N-Tier Database Systems
• N-tier database systems have at least
one middle component between the
client and the server
• FIGURE: A 2-tier versus an n-tier database
model.
• Additional tiers typically contain
middleware to connect to a database
• Allows program code to be separate
from the database
• Code can be divided into any number
of logical components
• Tiers can be used with different
platforms
• 2-TIER MODEL Has
just two parts: a
client and a server.
• N-TIER MODEL Includes
middleware, which contains
additional programs used to
connect the client and server tiers.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Centralized versus Distributed Database Systems
• Centralized database system
• Database is located on a single
computer, such as a server or
mainframe
• Distributed database system
• Data is physically divided among
several computers connected by a
network, but appears as a single
database to users
• Allows data to be stored at the site
where it is needed most
frequently or that makes data
retrieval most efficient
• Cloud databases
• FIGURE: Centralized versus distributed databases.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Disk-Based versus In-Memory Database Systems
• Disk-based systems
• Data is stored on hard drives
• In-memory databases (IMDBs) (main memory databases (MMDBs))
• All data is stored in main memory
• Use is growing as memory costs fall
• Dramatically faster than disk-based databases
• Good backup procedures are essential because RAM is volatile
• Used both in high-end systems where performance is crucial and in small-footprint,
embedded applications
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Database Models
• Hierarchical databases
• Organizes data in a tree structure
• Typically a one-to-many relationship between data entities
• Network databases
• Allow both one-to-many and many-to-many relationships between data elements
• Most common today: Relational databases, object-oriented database, and
multidimensional database
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
The Relational Database Model
• With a relational database management system (RDBMS), data is organized in
tables related by common fields
• most widely used database model today
• Designing a relational database
1. Identify the purpose of the database and the activities it will be used for
2. Determine the necessary fields and tables
3. Assign each field to a table
4. Reorganize as needed to minimize redundancy (normalization)
5. Finalize the structure (primary keys, field properties, etc.)
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Retrieving Information from a Relational Database:
Queries
• Most DBMSs come bundled with a set of tools to perform a variety of necessary
tasks, such as creating forms and reports and interfacing with query languages and
programming languages for complex applications.
• A query is a request to see information from a database that matches specific
criteria
• In Access, can create a query object that specifies what fields and records should be
displayed
• Or can write a query using structured query language (SQL)
• Each time a query is run, the data currently meeting the specified conditions is displayed
• Must be designed to extract information as efficiently as possible
• Poorly written queries can impact the overall performance of the system
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Reports
• Reports are a formatted way of looking at a database table or the results of a query
• Can pull data from more than one table (if related)
• Many programs have wizards or other tools to make it easy to create a report
• In Access, reports are often created using the Report Wizard and then modified as
needed using the report’s Design view
• Reports in Microsoft Access are saved as objects in the database file
• When a report is opened, the current data is displayed in the specified format
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
The Object-Oriented Database Model
• Object-oriented database management system (OODBMS) is a database system in
which multiple types of data are stored as objects along with their related code
• Can contain virtually any type of data (video clip, text with music, etc.) along with the
methods to be used with that data
• Objects can be retrieved using queries (object query language or OQL)
• Objects can be reused in other applications to create new applications quickly
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Hybrid Database Models
• Hybrid databases are a combination of
two or more database types or models
• E.g. object + relational database
technology = object-relational DBMS
• Hybrid XML/relational databases can
store and retrieve both XML data and
relational data
• DB2
• FIGURE: Hybrid XML/
relational databases.
Deborah Morley/Charles S. Parker, Understanding Computers: Today and Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Example of a Cloud Database in Action
FIGURE: A cloud
database in action.
•Deborah
Source:
L.L. Bean
Morley/Charles
S. Inc.;
Parker,Pryzmat/Shutterstock.com;
Understanding Computers: Today andNatalia
Tomorrow, Comprehensive, 16th Edition. © 2017 Cengage. All Rights
Reserved.
May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Siverina/Shutterstock.com
ENGR 20005
Introduction to
Cybersecurity
Chapter 1 Introduction to Computer Security
Identifying Types of Threats







Malware: MALicious softWARE
Security Breaches
DoS: Denial of Service attacks
Web Attacks
Session Hijacking
Insider Threats
DNS Poisoning
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
89
Malware

Software with a malicious purpose
 Virus
 Trojan horse
 Spyware
 Logic Bomb
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
90
Malware (cont.)
Virus



One of the two most common types
Usually spreads through e-mail
Uses system resources, causing slowdown or stoppage
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
91
Malware (cont.)
Trojan Horse


Named after
the wooden horse
of ancient history
The other most
common kind of
malware
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Chapter 1 Introduction to Computer Security
92
Malware (cont.)
Spyware

The most rapidly growing types of malware


Cookies
Key logger
Logic Bomb

Lays dormant until some logical condition is met, often a specific
date.
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
93
Compromising System Security
Intrusions

Attacks that break through
system resources



Hackers
Crackers
Social engineering
example_Youtube Video

War-driving
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Chapter 1 Introduction to Computer Security
94
Denial of Service Attacks


The attacker does not intrude into the system but just
blocks access by authorized users.
Very common attack
Web Attacks


The attacker attempts to breach a web application.
Common attacks of this type are SQL injection and
Cross Site Scripting.
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Chapter 1 Introduction to Computer Security
95
Session Hijacking


This is a complex attack that involves actually
taking over an authenticated session.
Not common
DNS Poisoning

This involves altering DNS records on a DNS server to
redirect client traffic to malicious websites, usually for
identity theft.
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
96
Basic Security Terminology
People:

Hackers





White hats - find some flaw in a system and report the flaw to the
vendor of that system
Black hats - cause some harm
Gray hats - breaks the law on occasion
Script kiddies - Inexperienced
Ethical hackers/ Sneakers/ Penetration Testers - Consultants
who are hired to do vulnerability assessments on company systems.
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
97
Basic Security Terminology (cont.)
Devices

Firewall


Proxy server


Filters network traffic
Disguises IP address of internal host
Intrusion Detection System

Monitors traffic, looking for attempted attacks
© 2019 by Pearson Education, Inc.
Chapter 1 Introduction to Computer Security
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Basic Security Terminology (cont.)
Activities
Authentication
Process of determining if the credentials given by a user or another system (such as
a username and password) are authorized to access the network resource in
question
 Auditing
Process of reviewing logs, records, and procedures to ensure established standards
are being met

© 2019 by Pearson Education, Inc.
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Network Security Paradigms

How will you protect your network?






CIA Triangle (confidentiality, integrity, and availability)
Least Privileges
Perimeter security approach
Layered security approach
Proactive versus reactive
Hybrid security method
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Chapter 1 Introduction to Computer Security
100
ENGR 20005
Introduction to Cybersecurity
Chapter 2 Networks and the Internet
Network Basics




A network is two or more connected computers
Connected via a Network Interface Card (NIC)
Uses a RJ 45 connector
Allows the host to connect to the network
RJ 45 connector
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Chapter 2 Networks and the Internet
102
Network Basics (cont.)
The hub is the simplest connection device


Creates a simple network
Sends traffic out all ports (no routing or switching)
The switch is a smart hub


Sends packets only to the intended host
Direct based on the MAC (Media Access Control) address
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Chapter 2 Networks and the Internet
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Network Basics (cont.)
A repeater is a device used to boost signal
 Two types of repeaters: amplifiers and signals
The router is more sophisticated
 Limits traffic to the intended network
 Directs traffic based on the IP address
 It is the location for security devices (Access Control lists,
firewalls, etc.)
 Programable
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Chapter 2 Networks and the Internet
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Network Basics (cont.)
Wi-Fi
IEEE 802.11 provides guidelines for wireless
networking.
 Wi-Fi Security
WEP (Wired Equivalent Privacy )
WPA (Wi-Fi Protected Access)
WPA2
WPA3

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Network Basics (cont.)
Port


A connection point
Not physical ports on a computer
SSH:22, DNS: 53, HTTP:80, HTTPS:443

Used by protocols to communicate
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Internet



To connect to the Internet, you log on to your Internet Service
Provider (ISP).
The ISP connects to another ISP or a backbone provider.
One backbone provider connects to another at a Network
Access Point (NAP).
© 2019 Pearson, Inc.
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Internet (cont.)
IP (Internet Protocol) Addresses




Necessary to navigate the Internet
It is a unique identifier, like a home address in
mail system
Usually in binary form
Consists of four octets separated by decimals
e.g. 192.168.123.132 (dotted-decimal format)
11000000.10101000.01111011.10000100 (binary address)
192.168.123.0 - network address. 0.0.0.132 - host address
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Internet (cont.)
The first octet defines the class to which the IP belongs.
Class
IP Range
for the
first byte
Use
A
0-126
Extremely large networks. No Class A network IP
addresses are left. All have been used.
B
128-191
Large corporate and government networks. All Class B IP
addresses have been used.
C
192-223
The most common group of IP addresses. Your ISP
probably has a Class C address.
D
224-247
These are reserved for multicasting (transmitting different
data on the same channel).
E
248-255
Reserved for experimental use.
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Internet (cont.)
Subnetting
Chop up a network IP address into smaller portions.
192.168.1.x (255 possible addresses)
 A subnet is a portion of a network that shares the
same subnet address.
 Subnet masks describe what subnet the address
belongs to.

Classless Inter Domain Routing (CIDR)
A way to describe the subnet with the IP address.
e.g. 192.168.1.10/24
 Variable-length subnet masking (VLSM)

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Internet (cont.)
IP V4



32-bit address
4.2 billion IP addresses
Will be replaced by IP V6
IP V6

128-bit address
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Internet (cont.)
Error Messages





100 series messages are informational.
200s are not seen because they indicate success.
300s are redirects.
400s are client errors.
500s are server errors.
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Chapter 2 Networks and the Internet
112
Basic Network Utilities

IPConfig can give you information about your system.
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Chapter 2 Networks and the Internet
113
Basic Network Utilities (cont.)

Ping tells if a system is
connected to the
network.

It also tells how long it
takes for an “echo
request” packet to arrive
at the destination host.
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Basic Network Utilities (cont.)

Tracert




“Ping deluxe.”
Uses the same syntax as
ping.
Shows every “hop”
between host and
destination address.
Useful tool for technicians
and hackers alike.
© 2019 Pearson, Inc.
Chapter 2 Networks and the Internet
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Basic Network Utilities (cont.)

Netstat


© 2019 Pearson, Inc.
Network status
Shows active connections
Chapter 2 Networks and the Internet
116
Basic Network Utilities (cont.)

NsLookup


Connect to DNS Server
Execute DNS related commands
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117
Open Systems Interconnect model (OSI) Model
HTTP, DNS, ...
SSL, SSH, JPEG, ...
API's Sockets, ...
TCP, UDP, ...
IP, IPSec, router, ...
Ethernet, Switch,
Bridge, ...
Fiber, Hubs, Wireless,
Repeaters, ...
Source: linuxhint.com
© 2019 Pearson, Inc.
Chapter 2 Networks and the Internet
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Project #4
1.
2.
3.
Using web resources, look up the DNS protocol.
Lookup these facts: who invented DNS protocol ? what is its
purpose? How is it used?
Write a brief paper describing what protocol does. Mention a bit
about who invented it, when and how it works.
119