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IT Applications Theory Slideshows By Mark Kelly McKinnon Secondary College By Mark Kelly Roles of hardware and software.

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Presentation on theme: "IT Applications Theory Slideshows By Mark Kelly McKinnon Secondary College By Mark Kelly Roles of hardware and software."— Presentation transcript:

1 IT Applications Theory Slideshows By Mark Kelly McKinnon Secondary College By Mark Kelly Roles of hardware and software components Version 2

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8 Input Devices Mouse, trackball – Designed for GUI OS – Ball mouse superseded by optical – RSI concerns – Trackball = stationary upside-down mouse Touchpad – When mice are impractical – On laptops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 – Digitises analogue 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 Voice recognition 1 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 Voice recognition 2 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 powerful than 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 Solid State Disk 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 data track 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 Disc Type Base speed (Mbit/s) Max speed (Mbit/s) “X factor” CD1.176556x DVD10.5521120x Blu-Ray36.0043212x

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.

51 Communication hardware Sends and receives data within and between systems Modem – Dialup (analogue) – ADSL – Cable internet

52 Cabling – CAT6 – Fibre optic – (Coaxial – extinct except for broadband) – USB, Firewire Wireless – 802.11 wifi radio – Microwave (corporate level only) – Infrared (extinct in PCs) Communication hardware

53 Switches, hubs Repeaters, bridges Routers Wireless Access Points File Servers Network Interface Cards More details in the Networks-Hardware PPT. Communication hardware

54 Stuff in the box Case – protects internal components. Needs good ventilation to prevent overheating – Tower – Desktop – Laptop, notebook Power supply unit (PSU) – Supplies voltage to the devices inside the case – Fan to cool the case PSU

55 Stuff in the box The case (chassis) Motherboard Power supply Memory Graphics card Expansion slots Ports

56 Motherboard Motherboard – the main circuit board to which all the system components connect Slots for – Memory – CPU – Expansion cards

57 Computer’s startup data stored in BIOS (Basic Input Output System) Flash RAM chips Hard disk type Amount of RAM Operating preferences Security password etc

58 Memory RAM – Random Access Memory holds running programs, current calculations, user preferences etc – Average RAM now = 1 to 4 gigabytes – Comes in chips on a little circuit board – Dynamic memory contents continuously leaking, so must be refreshed many times per second

59 Memory ROM – Read Only Memory contains control software that is burnt in the factory and never changes (e.g. a hard disk’s controller software) ROM variants – PROM (Programmable ROM) – EPROM (Erasable Programmable ROM)

60 Graphics Card A.K.A. video card Sometimes built into motherboard Creates screen image data Has its own processor – GPU – more powerful than the main CPU

61 Graphics Card Has a private data pipeline to the CPU for greater speed Expensive, powerful Outputs: – VGA (analogue) – DVI (digital) – HDMI

62 Graphics card Some cards have 2 VGA or DVI sockets to run two monitors The operating system splits the display across both monitors

63 Expansion Cards Plug into the computer’s bus (data highway) and become part of the system Allow new or better components to be added – Graphics – Sound card – Network card – Specialist circuitry to control exotic peripherals (external equipment plugged into the system)

64 Slots GENERAL PURPOSE Oldest – ISA and EISA Newer – PCI Newest – PCI Express VIDEO CARDS Older – AGP

65 Ports – where things plug in Also may find: PC Card (PCMCIA) SD card slot ESATA (high speed hard disk port) HDMI (digitial video + audio) DVI video Firewire

66 Ports USB (Universal Serial Bus) ports now replace many older single-purpose ports such as: – Keyboard – Mouse – Modem (serial port) – Printer Especially on notebooks/netbooks where space for ports is very limited Low-powered USB devices can be powered by the port – no power adaptor needed!


68 Software categories System software – Operating system – Network operating system Application software Utilities

69 System Software Operating system (OS) – Provides services to allow software to run – Allocates memory to programs – Controls multitasking – Controls hard disks and storage

70 OS – Commands the graphics card – Manages printing – Enables security – Negotiates with external hardware – Supports network and internet connectivity Microsoft Windows Linux Mac OS #70

71 System Software Network Operating system (NOS) – Runs on a file server – Controls a network just as an OS controls a computer – Manages logins and security – Issues privileges to users (e.g. home directory, printer access) – #71

72 NOS – Issues IP addresses for internet access – Caches downloads – Manages printers – Does backups Microsoft Windows Server 2008 Novell Netware (extinct) #72

73 Application Software Lets users get work done Designed to run on a particular OS Needs to be ported if it’s to run on other OSs. Examples: – Microsoft Office – Word, Excel, Powerpoint etc – Filemaker Pro database – Adobe Photoshop – #73

74 Utilities Specialised software that extends the functionality of a system Usually are single-purpose tools, e.g. – Windows Defrag – Notepad – Nero DVD burner – DivX, MP3 player – Calculator – Character map – XN View picture viewer and processor (#74)

75 By Mark Kelly These slideshows may be freely used, modified or distributed by teachers and students anywhere on the planet (but not elsewhere). They may NOT be sold. They must NOT be redistributed if you modify them. IT APPLICATIONS SLIDESHOWS

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