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INTRODUCTION TO COMPUTERS

INTRODUCTION TO COMPUTERS. What is a COMPUTER?. An electronic device, operating under the control of instructions stored in its own memory unit, that can accept data, manipulate data according to specific rules, produce information from the processing, and store the results for future use.

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INTRODUCTION TO COMPUTERS

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  1. INTRODUCTION TO COMPUTERS

  2. What is a COMPUTER? • An electronic device, operating under the control of instructions stored in its own memory unit, that can accept data, manipulate data according to specific rules, produce information from the processing, and store the results for future use.

  3. What is a COMPUTER? • A collection of devices that function together as a system. • Electronic devices • Contains • Memory • Instructions • Data is input • Processes data – according to rules • Outputs information • Stores results

  4. What does a Computer do? • Perform 4 general operations (Information Processing Cycle) • Input • Process • Output • Storage

  5. Data • A collection of raw facts, figures, & symbols • Numbers • Words • Images • Video • Sounds

  6. Information • Data that has been organized, is meaningful and useful • Can be sent to output • Printer • Web page • speaker • Can be stored • On disk

  7. Inside the Computer • Electronic circuits contained on small silicone chips • Circuits rarely fail • Data flows close to speed of light • Billions of processes per second

  8. Computer User • People who use the computer directly… • …or people who use the information it provides

  9. What are the Components of a Computer? • Input devices • Central processing unit (CPU) • Control unit • Arithmetic/logic unit • Memory • Output devices • Storage devices

  10. Input Devices - Keyboard Onscreen keyboard Numeric keypad 101-105 keys Notebook has built-in keyboard Handheld uses stylus and on- screen keyboard

  11. Input Devices – The mouse • Pointing device • Up to 5 buttons • Mechanism in bottom detects movement • Notebook computers – pointing device built-in Buttons Buttons Ball Wheel button Optical sensor Wheel button

  12. Central Processing Unit • CPU • Control unit • Interprets instructions • Arithmetic/logic unit • Performs the logical and arithmetic functions Celeron Duron Pentium Anthon

  13. Memory • Random Access Memory (RAM) • Stores any data to be processed • Typically measured in: • Kilobytes (K or KB) • 1,000 memory locations • Megabytes (M or MB) • 1,000,000 memory locations • 1 byte = 1 character • I megabyte  500 pages of text

  14. Output Devices - Printers • Impact Printers • Dot matrix • “Hammers” strike inked ribbon • “Carbon” copies

  15. Output Devices - Printers • Nonimpact printers • Ink-jet • Higher quality text and graphics • Quieter • BW or Color • Affordable • Laser • Work like copy machine • High quality • BW or color • More Expensive

  16. Output Devices - Screens • CRT • Television-like • Generally not compatible with TV • Fast refresh times • Large • Generate heat • Use more electricity • Environmentally difficult to dispose of (phosphors can be toxic)

  17. LCD (Liquid Crystal Display) Thin (small) Low power/low heat Large sizes are expensive Environmentally safer Poorer refresh rates (ghosts) Output Devices - Screens

  18. Output Devices - Screens • Resolution • Set by number of screen elements called pixels • A resolution of 600 X 800 • 480,000 pixels • Low resolution • “jaggy” lines vs

  19. Storage Devices • Auxiliary storage • Secondary storage • Store data when not being used in memory • Floppy disks • Hard disks • Compact disks • Magnetic tape

  20. Floppy Disk • Portable • Inexpensive • Thin, circular plastic disk with magnetic coating • Like recording tape

  21. Hard Disks • 1 or more rigid metal platters (disks) with magnetic metal oxide coating • Spin continuously • 5,400-7,200 rpm • Capacity • 10-200 GB • 1 GB = 1 billion bytes

  22. Compact Disks - CDs • CD –ROM • Read only • 650 MB • CD-R • Recordable • One time only • CD-RW • Rewritable • Acts like floppy disk • DVD-ROM • 4.7 – 17 GB

  23. Computer Software • System Software • Application Software

  24. System Software • Programs to control the operation of the computer equipment • BIOS • Operating system • Windows • GUI

  25. Application Software • Programs that tell the computer how to produce information • Business • Quicken – QuickBooks • Scientific • Analytical instrument control and data output • Educational • Tutorials – Grades – Registration – Quizzes • Personal • Word processing – spreadsheet – presentation graphics – database – communications – electronic mail - games

  26. Networks • A collection of computer and devices connected via communications media • Cables • Telephone lines • Modems • Wireless • Etc. • LAN

  27. Networks • LAN • A network that connects computers in a limited geographical area • School • Laboratory • Local business • Group of buildings

  28. Networks • WAN • A network that covers a large geographical area • District offices • International offices

  29. The Internet • World’s largest Network • Millions of computers • Over 360 million users • World wide • Reasons for using • Sending messages (e-mail) • Accessing information • Shopping • Meeting or conversing • Entertainment • Games • Magazines • Vacation planning guides

  30. The World Wide Web • One segment of the Internet • Contains billions of documents • Web pages • Web site • Collection of related web pages • Viewed using Web Browser • IE -Netscape

  31. URL • Uniform Resource Locator • Unique address of every web site (web page) Protocol HyperText Transfer Protocol Domain Name World Wide Web host computer ID page name

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