Computers and Society IST 2710

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Computers and SocietyIST 2710

• Section 006
• Class 5 2/6/08
• http//www.is.wayne.edu/drbowen/casw08

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Quiz Results

• Average is about 73, but some people did very
  badly
• Two blank diskettes CHECK!
• Many questions left blank NEVER DO THIS!
• Question 2 was worst
• 2A (2 types of storage) average 50
• 2B (6 stypes of computers) average 46
• 2C (data and information) average 60

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Quiz 1 Makeup

• Next week, Wednesday 2/13, 5 6 PM in the
  regular classroom.
• It will be different questions, from the same
  list. Some questions may, by chance, be repeated.
• If you missed the original Quiz, this is your
  chance to make it up.
• If you took the original Quiz but want to retake
  it, let me know by email.

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Staying for Lab

• Two or more labs or assignments behind, must stay
  during Lab to get 100 attendance credit tonight
  - 3 labs in, and 2 assignments in. Who must stay
• EVERYONE! (Unless you have turned more in
  tonight).

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Turning in Work

• Do not staple all of your work together
• If I cannot separate it easily, I will turn it
  back for you to separate
• Turn each assignment in separately
• Each lab
• Each homework assignment
• Each assignment should be stapled

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University closing info

• All of these
• Wayne State University Newsline 313-577-1498
• Wayne State University main websitewww.wayne.edu
  
• Pipeline
• Or sign up for email, text or cell call
• computing.wayne.edu gt services gt About WSU
  Broadcast Messaging

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Storing Pictures in a Computer

• Graphics
• Screen divided into pixels
• Seeing jaggies aliasing
• Smoothing edge anti-aliasing
• Computer stores a color code for each pixel
• Color code is RGB (amount of Red, Green, Blue)

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Color Codes

• Many different codes some examples
• Black and White, code is (usually) 1 bit for each
  pixel 0 is black, 1 white.
• Greyscale One byte per pixel (zero to 255)
• 0 is black, 255 is white, low numbers are dark
  shades, high numbers are bright shades
• High-quality black and white photo
• One-byte color 3 bits for red (0 to 7), 2 bits
  for green (0 to 3), 2 bits for blue
• Big jumps in colors, can get banding effect

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Color Codes

• Many different codes some examples
• 16-Bit color (High Color) 6-5-5. 65000
  colors, not bad
• 24-Bit or 3 Byte color (True Color) one byte
  each for Red, Green, Blue
• Good-quality color photo
• 32-Bit color. Some printers offering this. Screen
  cannot register more than 3, but printer can be
  higher resolution.

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Storing Graphics

• Bytes per graphic product of
• Number of pixels (number high times number wide)
• Color depth bytes per pixel
• Divide by Compression factor
• Bytes pixels high pixels wide bytes per
  pixel / compression factor
• Example How many bytes are required to store a
  graphic that is 80 pixels high by 60 pixels wide,
  with 2 Bytes per pixel and a compression factor
  of 5?
• David, change the homework

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Storing Data

• How many different values (or codes) can be
  stored in a given number of bits
• Do on board
• Work out
• Lowest value
• Highest value
• Number of different values

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Storing Data

• Work out
• Number of different values 2n
• Lowest value always 0 (zero)
• Highest value 2n 1
• Example
• How many different values can be stored in 5
  bits
• 25 32 different values
• Lowest value 0
• Highest value 25 1 32 1 31

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Chapter 4 Computer Security

• Why be worried? They ARE after you!
• Exploit bragging rights about skills
• Getting even
• Profit sell the use of your computer
• Zombie networks, advertized on Internet
• Physical security
• Protecting against unauthorized use
• UserID (public) and Password (secret)

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Security

• Hacking breaking into a computer
• Malware harmful software
• Virus corrupt files, infects others
• Worm runs many copies, slows computer, infects
  others
• Trojan horse disguised as something useful
• Denial of Service tie up a server with requests

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Protection

• Possessed Knowledge Access e.g., password
• Possessed Object Access e.g., card
• Biometric Access physical characteristic
• Firewall protects info in and out
• Anti-virus find and destroy viruses
• Encryption scrambling
• Public key/private key authenticates also Page
  133 Figure 4-12

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More Protection DB

• Strong password
• 6 to 8 characters
• Not the same password everywhere
• Not a dictionary work, or one backwards
• Not the name of you, relative, pet, or one
  backwards
• Use upper and lowercase
• Use characters, numbers and special characters
• Compound passwords two types

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More Protection - DB

• A good antivirus program
• Update data file AND scan engine
• Internet Security Suite
• Firewall Antivirus, work together
• Plus other features, such as alerting user if SSN
  or Credit Card Number leaves computer
• Total Security Suite
• Security Suite disk health backup

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Protection

• VPN uses encryption
• Virtual Private Network
• Wireless can be insecure if owner is not careful

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Online Problems

• Theft of data, etc.
• Identity theft put together enough info about
  you to act as you online
• Careful with SSN, mothers maiden name
• Scams
• Nigerian email
• If it seems to good to be true, it probably is
• Phishing
• Getting you to fill out private information

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Online Protection

• Be careful giving out information why do they
  need it?
• Give last four digits of Social Security Number
• Digital signatures and certificates
• Backing up
• USB drive and backup software

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Using Windows Explorer

• Get and start a laptop
• Getting it right in the first place
• Check diskette
• Fixing things NEVER START OVER!
• Drag a folder to the right place
• Editing a folder or file name
• Searching if it is not on your diskette, it is
  probably in My Documents

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Seeing File Extensions

• Windows Explorer
• Tools gt File Extensions
• Hide extensions for known file types
• This also changes whether or not you see file
  extension in all applications!

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Using Calculator for 2n

• Start Windows Calculator
• Scientific View
• Dec clicked
• Click these keys
• 2
• xy
• n

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Getting Lab Startup Files 1

• Added 2/7/08
• Go to the website for all of IST 2710 (different
  than website just for this section)
• Two ways to do this, use either one
• Go to www.is.wayne.edu/gst2710 (notice g, not
  i)OR
• Go to class website at www.is.wayne.edu/drbowen/ca
  sw08
• Scroll down and right-click on the file you need,
  then

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Getting Lab Startup Files 2

• Scroll down and right-click on the file you need,
  then
• On the shortcut menu click on Save Target As
  (Internet Explorer) or Save Link As (Firefox)
  or the link that is most like either of these
• Save the file to your floppy diskette
• Close Browser youre done with it
• More on next slide

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Getting Lab Startup Files 3

• You can now start the Tutorial
• When opening the file, do not use the location
  (folders) in the Tutorial, but instead use the
  location (path) that you save the file to.
• Similarly, when saving that or a changed file,
  save to that same location
• These directions are also on the Lab 5 sheet
  distributed in class