Transcript Slide 1

Chapter 1
Computers and Digital Basics
1 The Digital Revolution
 The digital revolution is an ongoing process of social,
political, and economic change brought about by digital
technology, such as computers and the Internet
 Revolves around a constellation of technologies, including
digital electronics, computers, communications networks, the
Web, and digitization
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1 The Digital Revolution
 Digital electronics use electronic circuits to represent data
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What are some examples of
digital devices?
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1 The Digital Revolution
 A computer network is a group of computers linked by wired
or wireless technology to share data and resources
 The Web is a collection of linked documents, graphics, and
sounds that can be accessed over the Internet
 Cyberspace is a term that refers to entities that exist largely
within computer networks
 Digitization is the process of converting text, numbers,
sound, photos, and video into data that can be processed by
digital devices
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1 Convergence
 Technological convergence is a process
by which several technologies with
distinct functionalities evolve to form a
single product
 Convergence tends to offer enhanced
functionality and convenience
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1 Digital Society
 Digital technology is an important factor in global and
national economies, in addition to affecting the economic
status of individuals
 Globalization can be defined as the worldwide economic
interdependence of countries that occurs as cross-border
commerce increases and as money flows more freely among
countries
 Individuals are affected by the digital divide, a term that
refers to the gap between people who have access to
technology and those who do not
 Digital technology permeates the very core of modern life
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1 Computer Basics
 A computer is a multipurpose device that accepts input,
processes data, stores data, and produces output, all
according to a series of stored instructions
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1 Computer Basics
 Computer input is whatever is typed, submitted, or
transmitted to a computer system
 Output is the result produced by a computer
 Data refers to the symbols that represent facts, objects,
and ideas
 Computers manipulate data in many ways, and this
manipulation is called processing
– Central Processing Unit (CPU)
– Microprocessor
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1 Computer Basics
 Memory is an area of a computer that temporarily holds data waiting to
be processed, stored, or output
 Storage is the area where data can be left on a permanent basis when it
is not immediately needed for processing
 A file is a named collection of data that exists on a storage medium
 The series of instructions that tells a computer how to carry out
processing tasks is referred to as a computer program
– Software
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1 Computer Basics
 A stored program means that a series of instructions for a
computing task can be loaded into a computer’s memory
– Allows you to switch between tasks
– Distinguishes a computer from other simpler devices
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1 Computer Basics
 Application software is a set of computer programs that
helps a person carry out a task
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Examples of Application
Software?
Microsoft Word, PowerPoint, Excel, Outlook, Adobe
Photoshop, and Blackboard...to name a few
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1 Computer Basics
 The primary purpose of system software is to help the
computer system monitor itself in order to function efficiently
– Operating system (OS)
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Examples of Operating
Systems?
Microsoft Windows 7, Mac OS X Snow Leopard, and
Linux...to name a few
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1
Personal Computers, Servers,
Mainframes, and Supercomputers
 A personal computer is a microprocessor-based computing
device designed to meet the computing needs of an
individual
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Personal Computers, Servers,
Mainframes, and Supercomputers
 The term workstation has two meanings:
– An ordinary personal computer that is connected to a
network
– A powerful desktop computer used for high-performance
tasks
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Personal Computers, Servers,
Mainframes, and Supercomputers
 A videogame console, such as Nintendo’s Wii,
Sony’s PlayStation, or Microsoft’s Xbox, are not
generally referred to as personal computers
because of their history as
dedicated game devices
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Personal Computers, Servers,
Mainframes, and Supercomputers
 The purpose of a server is to serve computers on a network (such as the
Internet or a home network) by supplying them with data
 A mainframe computer (or simply a mainframe) is a large and expensive
computer capable of simultaneously processing data for hundreds or
thousands of users
 A computer falls into the supercomputer category if it is, at the time of
construction, one of the fastest computers in the world
– A compute-intensive problem is one that requires massive amounts
of data to be processed using complex mathematical calculations
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1 PDAs, Smart Phones, and
Portable Media Players
 A PDA (personal digital assistant) is a pocket-sized digital
appointment book with a small qwerty keyboard or a touchsensitive screen, designed to run on batteries and be used
while holding it
 A handheld computer is essentially a PDA enhanced with
features such as removable storage, e-mail, Web access,
voice communications, built-in camera, and GPS
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1 PDAs, Smart Phones, and
Portable Media Players
 A smart phone, which in addition to voice communication,
includes features such as full qwerty keypad, text
messaging, e-mail, Web access, removable storage,
camera, FM radio, digital music player, and software options
for games, financial management, personal organizer, GPS,
and maps
 iPods and similar devices are classified as portable media
players because their main strength is playing music,
showing videos, and storing photos
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1 Microcontrollers
 A microcontroller is a special-purpose microprocessor that is
built into the machine it controls
 Microcontrollers can be embedded in all sorts of everyday
devices
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1 Data Representation
 Data representation refers to the form in which data is
stored, processed, and transmitted
 Digital devices work with distinct and separate data
 Analog devices work with continuous data
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Information stored in digital form generally takes up less space (ex.
music stored on an mp3 player vs. records)
Digital information is generally more secure
For more information on analog vs. digital read the
following article: http://www.explainthatstuff.com/analogand-digital.html
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1 Representing Numbers, Text,
and Pictures
 Numeric data
– Binary number system
 Character data
– ASCII, Extended ASCII,
EBCDIC, and Unicode
 Digitizing is the process of
converting analog data into
digital format
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Binary!
Switch
On = 1
Off = 0
0
1
1
0
1
1
0
1
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
First thing to remember....read the byte from right to left
To determine the decimal value of a byte we simply add
up the decimal values of the bits that are turned “on”
In this example which bits are turned “on”?
Switch
On = 1
Off = 0
0
1
1
0
1
1
0
1
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
In this example which bits are turned “on”?
Switch
On = 1
Off = 0
0
1
1
0
1
1
0
1
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
In this example bits 1, 3, 4, 6, and 7 are turned “on”
To determine the decimal value of the byte we add up the
decimal values of the “on” bits
Switch
On = 1
Off = 0
0
1
1
0
1
1
0
1
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
1 + 4 + 8 + 32 + 64 = 109
109 is the decimal value of this byte
What is the decimal value of this byte?
Switch
On = 1
Off = 0
0
0
1
0
0
0
1
0
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
What is the decimal value of this byte?
Switch
On = 1
Off = 0
0
0
1
0
0
0
1
0
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
2 + 32 = 34
34 is the decimal value of this byte
What bits do we have to turn on to
represent the decimal value 70?
Switch
On = 1
Off = 0
0
0
0
0
0
0
0
0
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
What bits do we have to turn on to
represent the decimal value 70?
Switch
On = 1
Off = 0
0
0
0
0
0
0
0
0
Bit
Position
8
7
6
5
4
3
2
1
128
64
32
16
8
4
2
1
Bit Value
in Decimal
We need to turn on bits 2, 3, and 7
2 + 4 + 64 = 70
1 Quantifying Bits and Bytes
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Processor or Virtual Storage
· 1 Bit = Binary Digit
· 8 Bits = 1 Byte
· 1024 Bytes = 1 Kilobyte
· 1024 Kilobytes = 1 Megabyte
· 1024 Megabytes = 1 Gigabyte
· 1024 Gigabytes = 1 Terabyte
· 1024 Terabytes = 1 Petabyte
· 1024 Petabytes = 1 Exabyte
· 1024 Exabytes = 1 Zettabyte
· 1024 Zettabytes = 1 Yottabyte
· 1024 Yottabytes = 1 Brontobyte
· 1024 Brontobytes = 1 Geopbyte
Disk Storage
· 1 Bit = Binary Digit
· 8 Bits = 1 Byte
· 1000 Bytes = 1 Kilobyte
· 1000 Kilobytes = 1 Megabyte
· 1000 Megabytes = 1 Gigabyte
· 1000 Gigabytes = 1 Terabyte
· 1000 Terabytes = 1 Petabyte
· 1000 Petabytes = 1 Exabyte
· 1000 Exabytes = 1 Zettabyte
· 1000 Zettabytes = 1 Yottabyte
· 1000 Yottabytes = 1 Brontobyte
· 1000 Brontobytes = 1 Geopbyte
http://www.whatsabyte.com/
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Abbreviations
Kilobyte - KB
Megabyte - MB
Gigabyte - GB
Terabyte - TB
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Which is bigger?
40 GB Hard Drive
or
50 MB Hard Drive
Answer: 40 GB Hard Drive
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Which is bigger?
500 KB
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1 TB
Answer: 1 TB
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1 Circuits and Chips
 An integrated circuit (computer chip) is a super-thin slice of
semiconducting material packed with microscopic circuit
elements
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1 Circuits and Chips
 The electronic components
of most digital devices are
mounted on a circuit board
called a system board or
mother board
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1 Programs and Instruction Sets
 Computers, portable media players, handheld computers,
and smart phones all work with digital data
 Computer programmers create programs that control digital
devices. These programs are usually written in a high-level
programming language
 The human-readable version of a program created in a highlevel language by a programmer is called source code
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1 Programs and Instruction Sets
A compiler converts all statements in a program in a single batch
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1 Programs and Instruction Sets
An interpreter converts and executes one statement at a time
while the program is running
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1 Programs and Instruction Sets
 An instruction set is a collection of preprogrammed activities
a microprocessor is hardwired to perform
 Each instruction has a corresponding sequence of 0s and 1s
 The end product is called machine code
– 1s and 0s
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1 Programs and Instruction Sets
 An op code (short for operation code) is a command word for
an operation such as add, compare, or jump
 The operand for an instruction specifies the data, or the
address of the data, for the operation
 In the following instruction, the op code is addition and the
operands are 5 and X
5+X
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1 Programs and Instruction Sets
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1 Processor Logic
 The ALU (arithmetic logic unit) is the part of the microprocessor that
performs arithmetic operations
 The ALU uses registers to hold data that is being processed
 The microprocessor’s control unit fetches each instruction, just as you
get each ingredient out of a cupboard or the refrigerator
 The term instruction cycle refers to the process in which a computer
executes a single instruction
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1 Processor Logic
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1 Processor Logic
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1 Authentication Protocols
 Security experts use the term authentication protocol to refer
to any method that confirms a person’s identity using
something the person knows, something the person
possesses, or something the person is
– A person can also be identified by biometrics, such as a
fingerprint, facial features (photo), or retinal pattern
– A user ID is a series of characters—letters and possibly
numbers or special symbols—that becomes a person’s
unique identifier
– A password is a series of characters that verifies a user
ID and guarantees that you are the person you claim to
be
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1 Password Hacks
 When someone gains unauthorized access to your personal data and
uses it illegally, it is called identity theft
 Hackers can employ a whole range of ways to steal passwords
 A dictionary attack helps hackers guess your password by stepping
through a dictionary containing thousands of the most commonly used
passwords
 The brute force attack also uses password-cracking software, but its
range is much more extensive than the dictionary attack
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1 Password Hacks
 If hackers can’t guess a password, they can use another
technique called sniffing, which intercepts information sent
out over computer networks
 An even more sophisticated approach to password theft is
phishing
 A keylogger is software that secretly records a user’s
keystrokes and sends the information to a hacker
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1 Password Security
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1 Password Security
 Strive to select a unique user ID that you can use for more
than one site
 Maintain two or three tiers of passwords
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1 Password Security
 A password manager stores user IDs with their
corresponding passwords and automatically fills in login
forms
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