1 / 75

IT Applications Theory Slideshows

IT Applications Theory Slideshows. IT Applications Theory Slideshows. Roles of hardware and software components. Roles of hardware and software components. By Mark Kelly mark@vceit.com Vceit.com. Version 2. By Mark Kelly McKinnon Secondary College Vceit.com. Information Systems.

Télécharger la présentation

IT Applications Theory Slideshows

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. IT Applications Theory Slideshows IT Applications Theory Slideshows Roles of hardware and software components Roles of hardware and software components By Mark Kelly mark@vceit.com Vceit.com Version 2 By Mark Kelly McKinnon Secondary College Vceit.com

  2. Information Systems Information System components: • Hardware • Software • Procedures • People • Data Usually systems are computers May be specialised e.g. railway ticket machines

  3. Hardware? Software? • Hardware is physical • E.g. a monitor • Can be touched, seen, picked up, kicked • Hardware needs software to operate • Software is programming instructions • E.g. Adobe Photoshop • Recorded as electronic binary signals • Controls hardware’s behaviour


  5. Unofficial ICT Hardware Categories • Input • Output • Processing • Storage • Communication

  6. Input Devices Let users enter data into an information system. • Keyboard, keypad • Mouse, touchpad • Bar code reader • Touch screen • Data tablet • Scanner, camera • Voice recognition

  7. Input Devices • Keyboard, keypad • QWERTY layout. Designed to be as inefficient as possible to stop fast typists jamming the early typewriters • Dvorak – more efficient key layout puts most commonly used keys on the home row. Rare!

  8. Input Devices • Mouse, trackball • Designed for GUI OS • Ball mouse superseded by optical • RSI concerns • Trackball = stationary upside-down mouse • Touchpad • When mice are impractical • On laptops

  9. Input Devices • Bar code reader • Reads bar codes – converts them to numbers • Common in supermarkets, libraries, parts warehouses etc • Much faster and more accurate than hand-typing product codes

  10. Input Devices • Touch screen • Touch sensitive • Tablet computers • iPhone • Railway ticket machines • Information kiosks • Bank ATMs • Easy for public to use • Can mimic any sort of interface: buttons are only images

  11. Input Devices • Data tablet • Far better than a mouse for art • Works like a pen • Pressure-sensitive

  12. Input Devices • Scanner, digital camera • Digitisesanalogue documents or pictures • Scans page like a photocopier • Use OCR (Optical Character Recognition) to interpret and digitise printed text • Resolution determines how detailed the resulting digital image is. • 1200 dpi resolution = 1200 dots per inch (2.54cm)

  13. Voicerecognition1 • Modern form of dictation • Requires complex programming to recognise voices accurately • Users need to train software to get used to their accent • Not useful in noisy environments, e.g. offices

  14. Voicerecognition2 • Not good for sensitive material – would be overheard! • May be useful if hands-free data entry needed • May be quicker data entry for poor typists

  15. Output devices 1 Display the results of processing. • Monitor • CRT • LCD, TFT • Plasma • Data projector

  16. CRT monitor • Now extinct!

  17. LCD monitors • LCD = Liquid Crystal Display • Thin, saves desk space • Lighter than CRT • Less power consumption than CRT • Getting cheaper • Refresh rates getting better • Blacks often just grey • Colour richness not as good as CRT

  18. Plasma • Very power-hungry • Cheap for very large displays (e.g. >40 inches) • Better blacks than LCD • Faster refresh than LCD • Good for public notice boards 150” (375cm) plasma display

  19. Data Projector • Very portable • Very large display • Struggles in brightly lit rooms • Colours are often dull • Excellent for group presentations • Lamps fail with age

  20. Output devices 2 • Printer • Laser • Inkjet • Thermal • Dot matrix, Impact • Speakers • Indicators, LEDs

  21. Laser Printers 1 • Black and white or colour • Expensive to buy, cheaper to run than inkjet • Fast printing • Prints whole page at a time, not line by line like inkjet

  22. Laser Printers 2 • Very high resolution (dots per inch) • Print is waterproof (unlike inkjet) • Same mechanicals as a photocopier

  23. Inkjet Printers • Cheap to buy, very expensive to replace ink • Line-by-line printing

  24. Thermal Printers • Low power requirements • Low to medium resolution • Can be battery powered - good for portable printing e.g. parking tickets • Uses heat-sensitive paper, usually on a roll

  25. Thermal Printers • Not good for archive documents – paper blackens over time • Often used for bar coding boxes,Point Of Sale (POS) terminals

  26. Dot matrix printers • Alias impact printer • In the print head are pins arranged in a matrix • They shoot out to hit an inked ribbon which is pushed against the paper leaving dots on it • Noisy! Slow! • Low resolution! Expensive ribbons… • but…

  27. Dot matrix printers • The only printer type that strikes the paper… • Only they can produce duplicates with pressure-sensitive paper • E.g. supermarket receipts - two or three copies (white customer copy, yellow shop copy) in only one print operation

  28. Other output devices • Speakers • Can use sound to give system alerts & information • Needed for playing audiovisual multimedia • Screen-recorded tutorials use voice-overs • Indicators, LEDs • Caps Lock, NumLock, hard disk activity, “power on” light etc • Watches, digital clocks • Car instrumentation

  29. Processing Hardware Converts data to information • CPU • RISC, CISC • Multicore • GPU

  30. CPU • Central Processing Unit • Most are CISC (Complex Instruction Set Computer) • Lots of inbuilt commands • Some are RISC (Reduced Instruction Set Computer) • Fewer inbuilt commands, simpler design • Smaller size, less power, less heat

  31. CPU • Many now have 2 or more cores – equivalent of multiple CPUs for extra processing power • Speed measured in hertz (cycles per second) • The more the hertz, the more work gets done in a fixed time • Usually measured in gigahertz • 2 to 4 GHz common nowadays

  32. CPU • Speed also can be measured in FLOPS • Floating Point Operations per Second • Benchmarks – standardised tests to measure CPU and whole-system performance.

  33. GPU • Graphics Processor Unit • A video card’s processor – much more powerful than a CPU (300%) • Needs power to shift huge quantities of data to the monitor

  34. GPU • Needs power to process complex video data (especially for gaming) • Now being used to help the CPU do processing • See nVidia’s Tesla – a GPU PC! 120 times more powerfulthan a normal PC.

  35. Storage hardware Stores & retrieves data and software. • Hard disk • Solid state disk • Flash RAM, RAM, ROM • CD, DVD • Tape, floppy disk

  36. Hard Disk Drive • ‘HDD’ • Magnetic storage • Multiple aluminium platters stacked on a spindle • Average HDD platters 3½” (inches) • Laptop platters 2½” • MP3 players 1”

  37. Hard Disks • Read/write heads move across top and bottom of each platter • Spin at 5,400, 7,000 or 10,000 rpm • Head floats on a cushion of air a couple of molecules distance from the platter A hard disk drive head resting on the disk platter.

  38. HDD • Very fast storage & retrieval • Very large capacity - 1.5 Terabytes • 1,500 gigabytes • Very cheap per megabyte • Must be handled gently • Draw quite a lot of current, reducing battery life

  39. SolidStateDisk • SSD • Permanent storage in Flash RAM • No moving parts – rugged & portable • Draw less current than HDD – longer battery life • Speed can be better than HDD • Expensive ($AU) • 128G SSD = $650 (2010) $235 (2011) • 1000G HDD = $77 (2011) • Small capacity compared to HDD

  40. USB Flash Drives • NAND memory • Normal RAM (Random Access Memory) loses its memory contents when power is turned off • Normal ROM (Read Only Memory) has its contents burnt at the factory and they cannot be changed later

  41. USB Flash Drives • Flash RAM can be rewritten like RAM but its contents are retained when power is lost. • Completely replaced floppy disks • Limited life – 1 million read/write cycles • 10 year data retention

  42. USB Flash drives • Small, light, rugged (sealed, no moving parts) • Cheap ones can be rather slow • Typical capacity from 64M to 64G. • Easily lost or left behind - possible security issues • Some USB Flash drives can be encrypted

  43. CD, DVD • Compact Disk – capacity about 700M • Digital Versatile Disk – about 4.7G (4700M) • Come in writeable and rewriteable forms • Writeable (CD-R, DVD-R) can be burnt (written to) once only – contents become permanent • Rewriteable (CD-RW, DVD-RW) can be erased and re-burnt several times.

  44. CD, DVD • Aluminium layer embedded in a 5¼” polycarbonate plastic disc • Laser burns data digitally as pits • Data also read by laser beam • Continuous, spiral datatrack extends from innermost to the outermost track, covering the entire disc surface

  45. CD, DVD • Sensitive to scratches, heat • Immune to magnetic effects • Not “perpetual storage” as originally believed. • Disks degrade over time, become unreadable • Gold disks seem to last longer The laser lens in a CD drive

  46. DVD • DVD media come in 3 types: • DVD-R • DVD+R • DVD-RAM • Also come in single/double layer versions • Most burners can write all 3 formats • Most players can play all 3 formats

  47. Blu-ray • Uses blue laser rather than red • Narrower beam can write more data in the same space • Compare writing with a thick red crayon and a sharp blue pencil

  48. CD vs DVD

  49. Tape & Floppy Disk • Magnetic storage – data can be damaged by magnetic fields; data can fade over time until it becomes unreadable • Read/write head rubs on the media surface – eventually wear off the magnetic coating

  50. Tape & Floppy Disk • DAT (Digital Audio Tape) commonly used for backup in corporate networks • Floppy disks – slow, low capacity, unreliable, expensive. EXTINCT.

More Related