IT Applications Theory SlideshowsIT Applications Theory Slideshows

By Mark KellyMcKinnon Secondary College

Vceit.com

By Mark Kellymark@vceit.com

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– Designed for GUI OS– Ball mouse superseded by optical– RSI concerns– Trackball = stationary upside-down mouse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 Kellymark@vceit.comvceit.com

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IT APPLICATIONS SLIDESHOWS