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  1. 1. IT Fundamentals 1. INPUT Much conversion of language occurs in a computer system (English) DATA INPUT DEVICE (binary) CPU (binary) OUTPUT DEVICE INFO (English) Input/ Output
  2. 2. IT Fundamentals Two types of input : Data and Instructions
  3. 3. IT Fundamentals Input Devices <ul><li>Provides: </li></ul><ul><ul><li>entry of data </li></ul></ul><ul><ul><li>Conversion into data format </li></ul></ul><ul><li>Most obvious = human + KEYBOARD </li></ul>Human data entry is called non-direct input. Machines make better input devices. DIRECT ENTRY , or SOURCE DATA AUTOMATION . Need to be: Accurate, reliable and easy to use, fast Human and keyboard is the most used input device
  4. 4. IT Fundamentals Examples of Direct Entry Input Devices - flat bed or hand-held - Similar to a photocopier - Reads page as a grid of dots - stores data as a &quot;picture&quot; MICR : Used with cheques Scanners
  5. 5. IT Fundamentals Examples of Direct Entry Input Devices Barcode Readers: Sit-in-the-Counter type - Reads standard or customised barcodes - Can also purchase software to print barcodes.
  6. 6. IT Fundamentals Input Types a. Data Collection Devices: Stocktake devices Automatic counters Web Cams Video camera whose output displays on a web page Digital Camera
  7. 7. IT Fundamentals Other Input Devices a. <ul><li>Sensors </li></ul><ul><li>Encode a physical event into data </li></ul>Pointing Devices Mouse
  8. 8. IT Fundamentals Other Input Devices TouchPad Pointing Stick Light Pen <ul><li>Trackball </li></ul><ul><li>Similar to mouse </li></ul><ul><li>Joystick </li></ul><ul><li>games </li></ul><ul><li>Touch screens </li></ul><ul><li>screen 'divided' into areas </li></ul><ul><li>area selected by touch </li></ul><ul><li>easy to use </li></ul><ul><li>cannot have areas too small </li></ul><ul><li>screens get dirty (many uses) </li></ul>
  9. 9. IT Fundamentals Voice Input <ul><li>Voice Input </li></ul><ul><li>hands free </li></ul><ul><li>trained for each voice </li></ul>
  10. 10. IT Fundamentals Output Four common type of output are text, graphics, audio and video.
  11. 11. IT Fundamentals Output Output Devices Digital signals from computer are converted into human readable form. Hard Copy - printer - plotter Soft Copy - screen - voice Printers <ul><li>Impact printers </li></ul><ul><li>Impact a solid image of a character onto an inked ribbon up against the paper. </li></ul><ul><li>Non-impact printers </li></ul><ul><li>no physical contact between paper and printing device </li></ul><ul><li>dot matrix concept used to form characters </li></ul>
  12. 12. IT Fundamentals Output <ul><li>Ink jet </li></ul><ul><li>quiet </li></ul><ul><li>Thermal </li></ul><ul><li>special paper </li></ul><ul><li>expensive to run </li></ul>
  13. 13. IT Fundamentals Output <ul><li>Laser </li></ul><ul><li>high speed, high quality </li></ul><ul><li>page printers </li></ul><ul><li>need enough memory to hold an entire page </li></ul><ul><li>600 to 2400 dpi </li></ul>
  14. 14. IT Fundamentals Output <ul><li>CRT Monitors </li></ul><ul><li>Raster scan technology </li></ul><ul><li>An electron beam moves back and forward across the back of the screen </li></ul><ul><li>This causes dots on the front of the screen to glow, producing an image </li></ul><ul><li>Available in various sizes 15 – 22 inches </li></ul><ul><li>Flat and curved screens </li></ul><ul><li>Resolution </li></ul><ul><li>Increase pixels/screen </li></ul><ul><li>Increase resolution (better image) </li></ul><ul><li>CRT monitors ( 1280 X 1024 pixels) </li></ul>
  15. 15. IT Fundamentals Output LCD Monitors <ul><li>Contains liquid crystals between 2 sheets of material </li></ul><ul><li>An electric current passes through the crystals causing them to twist, block light waves and create an image. </li></ul><ul><li>Uses less than one third the power of a CRT monitor </li></ul><ul><li>Lightweight and compact (mobile users) </li></ul><ul><li>Gas Plasma Monitors </li></ul><ul><li>A layer of gas instead of liquid crystals </li></ul>
  16. 16. IT Fundamentals Other Output Devices Data Projectors <ul><li>Fax Machine </li></ul><ul><li>Transmits and receives documents over the telephone line </li></ul><ul><li>Multifunction devices </li></ul><ul><li>Printer, scanner, copy machine and fax machine all in one </li></ul>
  17. 17. IT Fundamentals SECONDARY STORAGE Control Unit works on programs/data in RAM POWER OFF ... RAM OFF Bye Bye Assignment However blocks of memory can be saved/read on secondary storage.
  18. 18. IT Fundamentals Secondary Storage Media and Devices Floppy Disks Hard Disks Tape and Tape drive Cartridge tape CD-ROM DVD ROM Magnetic-Optical drive PC Cards Smart Cards SECONDARY STORAGE
  19. 19. IT Fundamentals FLOPPY DISKS: <ul><li>Circular piece of plastic </li></ul><ul><li>Made up of tracks & sectors </li></ul><ul><li>512 bytes in each sector </li></ul>
  20. 20. IT Fundamentals Maintaining data stored on a disk <ul><li>Made up of platters, cylinders and sectors </li></ul><ul><li>head 'floats' on surface </li></ul><ul><li>capacities range up to 200+ GB </li></ul>HARD DISKS
  21. 21. IT Fundamentals <ul><li>OPTICAL STORAGE TECHNOLOGY </li></ul><ul><li>high capacity is ideal for storage of the very large sound, graphics and video files </li></ul><ul><li>when recording data, laser light burns pits on CD </li></ul><ul><li>when reading data, pits will not reflect light (binary bit 0) but lands will reflect light (binary bit 1) </li></ul><ul><li>CD-ROM (compact disk read-only memory)- 650 MB of information </li></ul><ul><li>DVD (digital video disk) - 4.7 GB – 17 GB </li></ul>Hard Disk Vs Floppy Disk
  22. 22. IT Fundamentals Optical Storage
  23. 23. IT Fundamentals Optical Storage
  24. 24. IT Fundamentals TAPE <ul><li>Thin ribbon of plastic </li></ul><ul><li>Sequential storage – mainly for backup </li></ul>
  25. 25. IT Fundamentals OTHER TYPES OF STORAGE DEVICES <ul><li>PC cards </li></ul><ul><ul><li>Small, credit card-sized cards that fit into PC Card expansion slots </li></ul></ul><ul><ul><li>Used for storage, communications and additional memory. </li></ul></ul><ul><ul><li>Most often used with portable computers </li></ul></ul><ul><ul><li>Can store more than 300 MB of data </li></ul></ul><ul><li>Smart Cards </li></ul><ul><li>Credit card-sized devices that contain a microprocessor </li></ul><ul><li>Microprocessor can store up to 8,000 bytes of information. </li></ul><ul><li>Examples of uses - prepaid telephone card, employee time card </li></ul><ul><li>USB Drive </li></ul><ul><li>Flash memory storage device that plugs in a USB port </li></ul><ul><li>Small and lightweight </li></ul>