it applications theory slideshows by mark kelly mckinnon secondary college vceit.com by mark kelly...
TRANSCRIPT
IT Applications Theory SlideshowsIT Applications Theory Slideshows
By Mark KellyMcKinnon Secondary College
Vceit.com
By Mark [email protected]
Vceit.com
Roles of hardware and software componentsRoles of hardware and software components
Version 2
Information SystemsInformation System components:• Hardware• Software• Procedures• People• Data
Usually systems are computersMay be specialised e.g. railway ticket machines
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
HARDWARE
Unofficial ICT Hardware Categories
• Input• Output• Processing• Storage• Communication
Input DevicesLet users enter data into an information system.• Keyboard, keypad• Mouse, touchpad• Bar code reader• Touch screen• Data tablet• Scanner, camera• Voice recognition
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!
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– Designed for GUI OS– Ball mouse superseded by optical– RSI concerns– Trackball = stationary upside-down mouse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
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
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
Input Devices• Data tablet
– Far better than a mouse for art– Works like a pen– Pressure-sensitive
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)
Voicerecognition
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
Voicerecognition
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
Output devices 1Display the results of processing.• Monitor
– CRT– LCD, TFT– Plasma– Data projector
CRT monitor
• Now extinct!
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
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
Data Projector• Very portable• Very large display• Struggles in brightly lit rooms• Colours are often dull• Excellent for group presentations• Lamps fail with age
Output devices 2• Printer
– Laser– Inkjet– Thermal– Dot matrix, Impact
• Speakers• Indicators, LEDs
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
Laser Printers 2
• Very high resolution (dots per inch)
• Print is waterproof (unlike inkjet)
• Same mechanicals as a photocopier
Inkjet Printers• Cheap to buy, very expensive to replace ink• Line-by-line printing
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
Thermal Printers
• Not good for archive documents – paper blackens over time
• Often used for bar coding boxes,Point Of Sale (POS) terminals
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…
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
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
Processing HardwareConverts data to information• CPU
– RISC, CISC– Multicore
• GPU
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
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
CPU• Speed also can be measured in FLOPS
– Floating Point Operations per Second
• Benchmarks – standardised tests to measure CPU and whole-system performance.
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
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.
Storage hardwareStores & retrieves data and software.• Hard disk• Solid state disk• Flash RAM, RAM, ROM• CD, DVD • Tape, floppy disk
Hard Disk Drive• ‘HDD’• Magnetic storage• Multiple aluminium platters stacked on a
spindle• Average HDD platters 3½” (inches)• Laptop platters 2½”• MP3 players 1”
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.
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
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
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
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
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
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.
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
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
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
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
CD vs DVDDiscType
Basespeed(Mbit/s)
Max speed(Mbit/s)
“X factor”
CD 1.17 65 56xDVD 10.55 211 20xBlu-Ray 36.00 432 12x
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
Tape & Floppy Disk
• DAT (Digital Audio Tape) commonly used for backup in corporate networks
• Floppy disks – slow, low capacity, unreliable, expensive. EXTINCT.
Communication hardwareSends and receives data within and between
systems• Modem
– Dialup (analogue)– ADSL– Cable internet
• 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
• Switches, hubs• Repeaters, bridges• Routers• Wireless Access Points• File Servers• Network Interface Cards• More details in the Networks-Hardware PPT.
Communication hardware
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
Stuff in the box• The case (chassis)• Motherboard• Power supply• Memory• Graphics card• Expansion slots• Ports
Motherboard• Motherboard – the main circuit
board to which all the system components connect
• Slots for– Memory– CPU– Expansion cards
• 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
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
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)
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
Graphics Card
• Has a private data pipeline to the CPU for greater speed
• Expensive, powerful• Outputs:
– VGA (analogue)– DVI (digital)– HDMI
Graphics card• Some cards have 2 VGA or DVI sockets to run
two monitors• The operating system splits the display across
both monitors
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)
SlotsGENERAL PURPOSEOldest – ISA and EISANewer – PCINewest – PCI Express
VIDEO CARDSOlder – AGP
Ports – where things plug inAlso may find:• PC Card (PCMCIA)• SD card slot• ESATA (high speed
hard disk port)• HDMI (digitial
video + audio)• DVI video• Firewire
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!
SOFTWARE
Software categories
• System software– Operating system– Network operating system
• Application software• Utilities
System Software• Operating system (OS)
– Provides services to allow software to run– Allocates memory to programs– Controls multitasking– Controls hard disks and storage
OS
– Commands the graphics card– Manages printing– Enables security– Negotiates with external hardware– Supports network and internet connectivity
• Microsoft Windows• Linux• Mac OS• #70
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
NOS
– Issues IP addresses for internet access– Caches downloads– Manages printers– Does backups
• Microsoft Windows Server 2008• Novell Netware (extinct)• #72
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
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)
By Mark [email protected]
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