Transcript Introduction to Computers

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An electronic
device used to
process data.
The most common
computer today?
◦ the Personal
Computer.
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2%
3%
PCs In-Use (#M) 2005
2% 2%
1. U.S.
3%
3%
4%
2. Japan
34%
4%
3. China
4. Germany
4%
5. UK
5%
6. France
6%
7. South Korea
11%
8%
8. Italy
9%
9. Canada
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◦ Hardware
 the physical part of the computer
◦ Software
 the programs that run the hardware
◦ Data
 raw facts that are turned into useful information
◦ People
 the individuals that use computers (the user)
 the software and hardware designers
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◦ The Central Processing Unit (CPU)
 Intel Pentium
◦ Memory
 ROM and RAM
 Measured in bytes, kilobytes, megabytes, gigabytes, etc.
◦ Input and Output devices
 Moves data in and moves processed information out
◦ Storage devices
 Floppy disk drive, hard disk drive, CDROM, CDR, CDRW,
DVD drives, Zip drives
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The Central
Processing Unit
◦ Turns data into
useful information
◦ Is connected to the
motherboard
◦ Is the brain of the
computer
◦ Not the same thing
as “the box”
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Read Only Memory (ROM)
◦ Contains the information needed to boot the
system
◦ Nonvolatile (data cannot be changed)
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Random Access Memory (RAM)
◦ Working memory
◦ Volatile (is lost when machine is turned off)
◦ The more RAM, the faster the computer will run
and the more it can do
◦ The more software you can upgrade before
having to upgrade hardware
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Accept data and instructions from the user
◦
◦
◦
◦
◦
◦
◦
Keyboards
Mice and Trackballs
Touch-Screen Monitors
Scanners
Microphones
Digital Cameras
IPods
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Return processed information back to the
user.
◦ Floppy Disk drive
◦ Printer
◦ Monitor
◦ Hard drive
◦ CD’s/DVD’s
◦ Speakers, IPods
◦ Key Drives (USB port
hard drives)
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Holds data
Large storage
capacity
◦ measured in
 Megabytes (Mb)
 one million bytes
 Gigabytes (Gb)
 one billion bytes
 Terabytes (Tb)
 one trillion bytes
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Nonvolatile
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Hard drives
Floppy Disk drives
Tape drives
Optical drives
◦ Compact Disks
 CD-ROM, CD-R & CD-RW
◦ Digital Versatile Disks
 DVD, DVD-R & DVD-RW
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New Drives on the
Horizon?
◦ Plasma drives
◦ Holographic
imaging drives
◦ Portable hard drives
 Thumb drives
 Memory sticks
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A set of instructions
When executed tells the computer and
its peripheral devices
◦ what actions to perform and
◦ in what order to perform them
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System Software
◦ Operating systems, such as Windows (Vista, XP &
2000), DOS, Linux, iMac, AS400
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Application Software & Suites
◦ Word processing, Spreadsheets, Databases,
Multimedia, Presentation & Graphics,
Entertainment, Education, Utilities,
Communications
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Supercomputers
Mainframes
Minicomputers
The Cray
IBM 360, AS400
System 36/38
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Microcomputers
(PCs)
◦ Workstation
◦ Desktop
◦ Laptop or
Portable
◦ Personal Digital
Assistant
(PDAs)
◦ eBook
◦ Tablet
◦ Blackberry
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Binary Numbering System
◦ Uses 2 digits: 0 and 1
◦ All data is stored within the computer as 0’s and
1’s.
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Decimal Numbering System
◦ Uses 10 digits: 0, 1, 2, 3, 4, 5,
6, 7, 8 & 9

Other Numbering Systems
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A Bit
◦ The smallest possible unit of data.
◦ In binary, either a 0 or a 1.
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A Byte
◦
◦
◦
◦
A combination of 8 bits.
Used to represent up to 256 different values.
Used to represent characters.
Ex.
0100 0001 = A
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ASCII
◦ An 8-bit coding system used on personal
computers.
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Unicode
◦ A 16-bit coding system used to represent
characters from almost every language in the
world.
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Don’t skimp on
memory
Purchase as much disk
space as possible
Review online reviews
of hardware & software
Don’t forget the
bundled software
Don’t forget your
surroundings
Insist on a 30-day
unconditional return
policy for full refund


Insist on a price
guarantee; i.e., if the
price goes down within
30 days, you are
entitled to the rebate
Pay with a credit card
◦ Increases leverage to
enforce above items
◦ May double the
manufacturer’s warranty
up to an additional year
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Connect computers
◦ Uses telephone lines from one location to
another.
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Measured in transfer rates of bits per
second
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Example of an Analog Signal
Sound
No Sound
Example of a Digital Signal
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Tin can
Modem
Modem
Analog Signal
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Connect computers together so that they
can communicate, exchange information,
and pool resources.
Are connected by nodes
Categories
◦
◦
◦
◦
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
Internet
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File server networks
1.
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A central computer with a large hard disk
serves as a common place to store and
access files.
Processing is
restricted to the
file server.
Restricts access
by nodes
to file server.
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Client/Server
networks
2.
◦
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Shares both files
and programs
with the nodes.
Processing is
shared between
the server and
the nodes.
What you’re on in
here!
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Peer-to-peer
networks
2.
◦
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All nodes share
resources equally.
All nodes can act
as file servers and
can access
common
peripherals.
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A file is a set of instructions or data
◦ Program file:
 Microsoft Word or Microsoft Excel
◦ Data File:
 Document or workbook
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Copy, move, rename or delete a file
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Folder
◦ allows us to organize our files
◦ May contain files and/or other folders
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Back up strategy -- is critical
◦ What (data), When (whenever it changes), Where
(off site), How (Windows Explorer), and Who (you)
◦ Back up your work!
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The complement to ARPANET.
Became higher-capacity network
The backbone of the Internet
Could handle the increased user load
Developed into a much larger network
sharing information among
 government,
 business and
 commercial enterprises.
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Individual PCs are
connected to a
local area network.
Then connected via
a router to the
Internet using a
TCP/IP connection
Then connected to
other LANs.
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Router
TCP/IP

Internet
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TCP/IP
◦ Transmission Control Protocol/Internet Protocol
◦ The universal language of the Internet
◦ Includes the specifications that identify individual
computers and the exchange of data between
computers.
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IP (Internet Protocol) the 4-part numeric
address that identifies each computer.
◦ 10.2.2.166
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DNS (Domain Name System) the name
counterpart to the IP address.
◦ [email protected]
◦ Easier to use than remembering number
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D O M A IN
T Y P E O F O R G A N IZ A T IO N
.c o m
B u s in e ss (c o m m e rc ia l)
.e d u
E d u c a tio n a l
.g o v
G o ve rn m e n t
.m il
M ilita ry
.n e t
G a te w a y o r H o s t
.o rg
A n y o th e r typ e o f o rg a n iz a tio n
Examples:
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owc.edu
uwf.edu
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An exchange of
electronic information
Can also include data
files and program files
to email messages
No expectation of
privacy
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Every e-mail address is
unique
You can obtain an
account
◦ Through your school,
◦ pay for an account
through an ISP such as
AOL, or
◦ get free email accounts at
sites like
www.hotmail.com or
www.yahoo.com or
www.gmail.com
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Consists of two parts
◦ A username and a host computer
[email protected]
Highest-level domain
Host computer
Username
A good Internet E-mail
Address
must contain the @ symbol
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•
E-commerce is the exchange of goods and
services via the Internet.
– It requires a buyer and seller, and a ‘place
to meet’

Advantages for the Seller
◦ Open 24/7
◦ Shoppers from anywhere
◦ Virtual inventory is
cheaper and extensive
◦ Lower transaction costs
◦ Target your customers

Advantages for the
Buyer
◦ Open 24/7
◦ Never leave home
◦ Easy to view and
explore product line
◦ Comparison shop
◦ Web site knows you
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News & News Groups
◦ A form of public bulletin board
◦ Each news group is dedicated to one particular
subject
◦ Can quickly become an annoyance!
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FTP (File Transfer Protocol)
◦ A tool used to copy files from one computer to
another.
◦ Allows you to upload content to a website
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Internet Relay Chat
(IRC)
◦ Chat rooms
◦ a means of
communicating with
others in real time
◦ Play Safe!
Don’t give
out your
name or
anything
personal!
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The World Wide Web
 Created in the late 1980’s at the
European Particle Physics
Laboratory in Geneva, Switzerland
 A method for incorporating footnotes,
figures, and cross-references into online
hypertext documents
◦ Uses
 HTTP (Hypertext Transfer Protocol) and
 HTML (Hypertext Markup Language)
 HTTPS (Hypertext Transfer Protocol Secure)
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◦ HTTP (Hypertext Transfer Protocol)
 a set of rules that provide the internal structure to the
WWW
◦ HTML (Hypertext Markup Language).
 A page-description language that translates
document formatting to formatting for the Web
◦ HTTPS
 Secure protocol for confidential transactions
◦ URL (Uniform Resource Locator)
 Internet address in a special format that can be read
by HTTP.
 Ex.
http://www.yahoo.com
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Web browsers make negotiating the Web
easier.
◦ Most well-known browsers





Internet Explorer
Firefox (Mosaic/Mozilla)
Safari
Netscape Navigator
With IE and Firefox making
81.28%
12.96%
3.93%
(< 1%)
up over 90% of the market
Percentages from PC Magazine, January 2007
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•High-Speed Data Links - Cost More!

Cox Cable

◦ connection made through
TV cable
◦ up to ten times as fast as
regular telephone lines

◦ A family of digital
telecommunications
protocols designed to
allow high speed data
communication over the
existing copper telephone
lines between end-users
and telephone companies.
ISDN (Integrated Services
Digital Network)
◦ combines voice, data, and
control signaling through
a single dedicated circuit
◦ can transfer data at rates
up 128,000 bits per
second.
DSL (Digital Subscriber
Line)

Hughes.net (Direcway)
◦ Connection made through
Satellite
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Protection

◦ Firewalls
◦ Netiquette
 used to control access
to individual networks
 Guidelines
 Netiquette by Virginia
Shea
◦ Passwords
 used to restrict access
to files, programs or
networks
 A1234z is better than




Spouse’s name
Pet’s name
Last 4 SS numbers
Anniversary or Birthday
dates
Courtesy
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Ethics
◦ FBI Internet Fraudulent
◦ Urban Legends
◦ Hoaxbusters
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Password
Length
36 (no case,
letters &
digits)
0 minutes
52 (case
sensitive)
96 (all printable
characters)
4
26 (no upper
case/
letters only
0 minutes
1 minute
12 minutes
5
0 minutes
10 minutes
1 hour
22 hours
6
50 minutes
6 hours
2.2 days
3 months
7
22 hours
9 days
4 months
23 years
8
24 days
10.5 months 17 years
2,287 years
9
21 months
32.6 years
881 years
219,000 years
10
45 years
1,159 years
45,858 years 21 million years
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Forwarding
Chain letters
If you love me…
Scams
◦ No kidding! I really know this person!
◦ Kidney Transplant
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