Monitors (VDU)

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Macquarie Fields College of TAFE
Version 2 13 March 2000 3 - HARDWARE
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Types of Computers
Macquarie Fields College of TAFE

• Minicomputers
• Powerful
• General Purpose
• 50/100 MIPS
• Microcomputers
• Single silicon chip (CPU)
• Desktop/Laptop
• 5/20 MIPS

• Super computers
• 250 MIPS
• Multiple Processors
• Mainframes
• Large Fast
• Networked 100/200 MIPS

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Issues Surrounding Computers
Macquarie Fields College of TAFE

• Cost
• Security/Passwords
• Customisation
• Ease of use
• Performance

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Monitors (VDU)
Macquarie Fields College of TAFE

• Another term for display screen. The term
  monitor, however, usually refers to the entire
  box, whereas display screen can mean just the
  screen. In addition, the term monitor often
  implies graphics capabilities.
• There are many ways to classify monitors. The
  most basic is in terms of colour capabilities,
  which separates monitors into three classes.

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Monitors - Colour
Macquarie Fields College of TAFE

• Monochrome Monochrome monitors actually display
  two colours, one for the background and one for
  the foreground. The colours can be black and
  white, green and black, or amber and black.
• Gray-scale A gray-scale monitor is a special
  type of monochrome monitor capable of displaying
  different shades of gray.

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Monitors - Colour
Macquarie Fields College of TAFE

• ColourColour monitors can display anywhere from
  16 to over 1 million different colours. Colour
  monitors are sometimes called RGB monitors
  because they accept three separate signals --
  red, green, and blue.

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Monitors - Size
Macquarie Fields College of TAFE

• screen sizes are measured in diagonal inches, the
  distance from one corner to the opposite corner
  diagonally.
• A typical size for small VGA monitors is 14-15
  inches.
• Monitors that are 16 or more inches diagonally
  are often called full-page monitors.

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Monitors - Resolution
Macquarie Fields College of TAFE

• The resolution of a monitor indicates how densely
  packed the pixels are. In general, the more
  pixels (often expressed in dots per inch), the
  sharper the image.
• Most modern monitors can display 1024 by 768
  pixels, the SVGA standard. Some high-end models
  can display 1280 by 1024, or even 1600 by 1200.

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Printers
Macquarie Fields College of TAFE

• A printer is a peripheral device that is attached
  to a computer and is used to transfer data from
  the computer to paper producing a hard copy.

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Types of Printers
Macquarie Fields College of TAFE

• Impact
• Dot Matrix
• Daisy Wheel

• Non-impact
• Laser
• Ink jet/bubble jet
• Plotter

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Which printer should I get?
Macquarie Fields College of TAFE

• Printers are designed for just about everybody
  and everything from black and white to
  architectural design, colour printouts or high
  quality designs.
• Lets look at the advantages and disadvantages of
  the types already discussed.

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Advantages/Disadvantages of Different Printers
Macquarie Fields College of TAFE

• LASER PRINTER
• AdvantagesHigh quality printoutsFastReasonably
  pricedQuiet
• DisadvantagesCostly to maintain - Expensive to
  replace cartridges and the number of output is
  half to inkjetBulky in size

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Advantages/Disadvantages of Different Printers
Macquarie Fields College of TAFE

• INK JET/BUBBLE JET
• AdvantagesReasonable qualityCost
  EffectiveQuietFast
• DisadvantagesInk will run if wetCartridges can
  be expensive to replace

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Advantages/Disadvantages of Different Printers
Macquarie Fields College of TAFE

• PLOTTER
• AdvantagesCan print larger than A3 paperCan
  print in thin intricate lines used for 3D, map
  and design drawings
• DisadvantagesExpensive to purchaseSlow to print

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Advantages/Disadvantages of Different Printers
Macquarie Fields College of TAFE

• DOT MATRIX/DAISY WHEEL
• Advantages- Can print multiple copies as the
  impact printer strikes carbonised sets
• Can print continuous paper
• Disadvantages- Slow- Noisy- Ribbons are
  becoming more expensive as machines are becoming
  more extinct

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ASCIIAmerican Standard Code for Information
Interchange
Macquarie Fields College of TAFE

• Represents all letters, numbers and characters on
  keyboards
• 01000001 A
• 01010100 T
• 8 bits 1 byte 1 character

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ASCIIAmerican Standard Code for Information
Interchange
Macquarie Fields College of TAFE

• There are 256 possible combinations of ASCII
  code. The ASCII character set shown here
  represents the capital letter A as 65, T as
  84, lower a as 97 and ½ as 171.

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ASCIIAmerican Standard Code for Information
Interchange
Macquarie Fields College of TAFE
128 64 32 16 8 4 2 1
0 1 0 0 0 0 0 1 65 A 01000001
0 1 0 1 0 1 0 0 84 T 01010100
0 1 1 0 0 0 0 1 97 a 01100001
1 0 1 0 1 0 1 1 171 ½ 10101011
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ASCIIAmerican Standard Code for Information
Interchange
Macquarie Fields College of TAFE

1 Byte

• 0 1 0 0 0 0 1 0

1 Bit
(Binary Digit)
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MemoryUnits of Measurement
Macquarie Fields College of TAFE
1 BIT 0s or 1s 8 BITS 1 BYTE (1
character) 1,000 BYTES 1 KILOBYTE (1
thousand) 1,000 KILOBYTES 1 MEGABYTE (1
million) 1,000,000 1,000 MEGABYTES 1 GIGABYTE
(1 billion) 1,000 million 1,000,000,000 1,000
GIGABYTES 1 TERABYTE (1 trillion) 1 million
million (1012)

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Security
Macquarie Fields College of TAFE

• Refers to techniques for ensuring that data
  stored in a computer cannot be read or
  compromised. Most security measures involve data
  encryption and passwords. Data encryption is the
  translation of data into a form that is
  unintelligible without a deciphering mechanism. A
  password is a secret word or phrase that gives a
  user access to a particular program or system.

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Passwords
Macquarie Fields College of TAFE

• A secret series of characters that enables a user
  to access a file, computer, or program. On
  multi-user systems, each user must enter his or
  her password before the computer will respond to
  commands. The password helps ensure that
  unauthorized users do not access the computer. In
  addition, data files and programs may require a
  password.

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Security/Passwords
Macquarie Fields College of TAFE

• Encryption
• Passwords
• Security Levels
• Attributes
• Backups