EGAC 1010

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Essential introduction to computers Part 1
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Outline

• Computers and computer literacy
• What is a computer?
• The information processing cycle
• Data versus information
• Components of a computer
• Input devices
• The central processing unit
• The main memory
• Output devices
• Where does the power of a computer come from?
• Hardware versus software

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Computers and computer literacy

• Examples of computers?
• Desktop, laptop, palmtop,
• Computer literacy
• Knowledge of the computer components
• Knowledge of how a computer works
• Knowledge of computer uses

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Bell Telephone Labs Holmdel, NJ
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UNIX Most Popular High End OS
Ken invented UNIX in cooperation with Dennis and
Dennis invented the C Programming Language
Dennis Ritchie
Ken Thompson
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UNIX On A PDP-11 In 1971This was Dr. Browns
First Ever Personal Computer.012 MB RAM!
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Moores Law Says It All
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What is a computer?

• A computer is a programmable, multiuse machine
  that
• Accepts input
• Processes it
• Stores the processing results
• Provides output
• Communicates with others (For example Other
  computers on a network such as the Internet)

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A desktop computer and other computer hardware
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The information processing cycle

• Basic operations of a computer
• Input
• Processing
• Output
• Secondary storage

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Data versus information

• Data --gt Facts
• Information --gt Meaning

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Components of a computer
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Components of a computer

• Five major categories of devices
• Input devices
• System unit -- Processing memory (CPU RAM)
• Output devices
• Storage devices
• Communications devices
• Note Input, output, storage, and communications
  devices are also called peripheral devices

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Components of a computer ...

• Examples of computer devices
• Input --gt Keyboard Mouse Scanner
• System unit --gt CPU Main Memory
• Output --gt CRT Printer Sound
• Secondary storage --gt Floppy Disk Hard Disk
  Magnetic Tape Optical Disc (CD-ROM)
• Communications --gtWired Wireless Modem

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Components of a computer ... The keyboard

• A typical keyboard has
• Standard typewriter keys -- QWERTY
• Enter key or Return key
• Cursor movement keys
• Numeric keys
• Function keys -- For frequent tasks
• Special-purpose keys -- Backspace, Delete,
  Insert, Esc, Ctrl, and Alt.
• The start key is used for accessing system
  resources in Windows.

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Standard Typewriter Keys
Function Keys
Numeric Keypad Keys
The keyboard ...
Special Purpose Keys
Cursor Movement Keys
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Components of a computer ... The mouse

• The mouse is used with a Graphical User Interface
  (GUI).
• Usage
• Rolled about on a desktop -- Directs a pointer on
  the screen.
• Has a number of buttons (a wheel).
• Can be used to click on an item or to drag it
  and drop it.
• Types of mice
• Mechanical
• Optical
• Cordless

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Components of a computer ... The Central
Processing Unit
CPU carries out instructions retrieved from main
memory.
C U
CPU contains the CU and the ALU
ALU
Registers
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Components of a computer ... The main memory

• Also known as memory, primary storage, internal
  memory, or Random Access Memory (RAM).
• It is the working storage or working space.
• Holds data, instructions, and intermediate
  results.

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Components of a computer ... CPU versus main
memory
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Components of a computer ... Printers

• Impact printers Dot matrix printers are the most
  common impact printers.
• Non-impact printers
• Ink-jet printers
• Laser printers
• Measuring the speeds of different printers

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Components of a computer ... Computer screens

• Cathode Ray Tube (CRT) screens
• Liquid Crystal Display (LCD) screens
• The pixel is the smallest unit of any screen
  image
• Measuring the resolutions of different computer
  screens

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Where does the power of a computer come from?

• Five factors make a computer powerful in carrying
  out its basic operations
• Speed
• Reliability
• Accuracy
• Storage capacity
• Ability to communicate with other computers

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Hardware versus software

• Hardware ? Circuitry and physical components
• Software (also programs or computer programs)
  consist of step-by-step instructions that tell
  the computer how to perform tasks
• Each program is written in a computer programming
  language
• Most computers carry out the instructions of a
  program in a sequential manner (meaning one
  instruction after another until the whole program
  is completed)