Macquarie Fields College of TAFE
description
Transcript of Macquarie Fields College of TAFE
Macquarie Fields College of TAFE
Version 2 – 13 March 20003 - HARDWARE
3
Types of Computers
• 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
Macquarie Fields College of TAFE
Issues Surrounding Computers
• Cost
• Security/Passwords
• Customisation
• Ease of use
• Performance
Macquarie Fields College of TAFE
Monitors (VDU)• 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.
Macquarie Fields College of TAFE
Monitors - Colour• 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.
Macquarie Fields College of TAFE
Monitors - Colour
• Colour
Colour 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.
Macquarie Fields College of TAFE
Monitors - Size• 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.
Macquarie Fields College of TAFE
Monitors - Resolution• 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.
Macquarie Fields College of TAFE
PrintersA 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.
Macquarie Fields College of TAFE
The printer uses a parallel connection that has 25 pins. This is used so that the information can be processed at 8 bits (1 byte) at a time.
Types of Printers
• Impact
– Dot Matrix
– Daisy Wheel
• Non-impact
– Laser
– Ink jet/bubble jet
– Plotter
Macquarie Fields College of TAFE
Which printer should I get?
Printers are designed for just about everybody and everything – from black
and white to architectural design, colour printouts or high quality designs.
Let’s look at the advantages and disadvantages of the types already
discussed.
Macquarie Fields College of TAFE
Advantages/Disadvantages of Different Printers
LASER PRINTER• Advantages
High quality printoutsFastReasonably pricedQuiet
• DisadvantagesCostly to maintain - Expensive to replace cartridges and the number of output is half to inkjetBulky in size
Macquarie Fields College of TAFE
Advantages/Disadvantages of Different Printers
INK JET/BUBBLE JET• Advantages
Reasonable qualityCost EffectiveQuietFast
• DisadvantagesInk will run if wetCartridges can be expensive to replace
Macquarie Fields College of TAFE
Advantages/Disadvantages of Different Printers
PLOTTER• Advantages
Can print larger than A3 paperCan print in thin intricate lines used for 3D, map and design drawings
• DisadvantagesExpensive to purchaseSlow to print
Macquarie Fields College of TAFE
Advantages/Disadvantages of Different Printers
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
Macquarie Fields College of TAFE
ASCIIAmerican Standard Code for Information Interchange
• Represents all letters, numbers and characters on keyboards
• 01000001= A
• 01010100= T
• 8 bits = 1 byte = 1 character
Macquarie Fields College of TAFE
ASCIIAmerican Standard Code for Information Interchange
• 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.
Macquarie Fields College of TAFE
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
ASCIIAmerican Standard Code for Information Interchange
0 1 0 0 0 0 1 0
Macquarie Fields College of TAFE
1 Bit
1 Byte
(Binary Digit)
MemoryUnits of Measurement
Macquarie Fields College of TAFE
1 BIT = 0’s or 1’s8 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)
÷
Security
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.
Macquarie Fields College of TAFE
Passwords
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.
Macquarie Fields College of TAFE
Security/Passwords
• Encryption
• Passwords
• Security Levels
• Attributes
• Backups
Macquarie Fields College of TAFE