Transcript IT Applications Theory Slideshows

IT Applications Theory Slideshows
Roles of hardware and
software components
Version 2
By Mark Kelly
Information Systems
Information System components:
• Hardware
• Software
• Procedures
• People
• Data
Usually systems are computers
May be specialised e.g. railway ticket machines
Hardware? Software?
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Hardware is physical
E.g. a monitor
Can be touched, seen, picked up, kicked
Hardware needs software to operate
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Software is programming instructions
E.g. Adobe Photoshop
Recorded as electronic binary signals
Controls hardware’s behaviour
HARDWARE
Unofficial ICT Hardware Categories
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Input
Output
Processing
Storage
Communication
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
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– Ball mouse superseded by optical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)
• 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
Voice
recognition
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• 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
Voice
recognition
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Output devices 1
Display the results of processing.
• Monitor
– CRT
– LCD, TFT
– Plasma
– Data projector
CRT monitor
• Now extinct!
LCD monitors
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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
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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
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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
• Speakers
Other output devices
– 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 Hardware
Converts 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 powerful
than a normal PC.
Storage hardware
Stores & 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
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
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
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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
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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 DVD
Disc
Type
CD
DVD
Blu-Ray
Base
speed
(Mbit/s)
1.17
10.55
36.00
Max
speed
(Mbit/s)
65
211
432
“X factor”
56x
20x
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 hardware
Sends and receives data within and between
systems
• Modem
– Dialup (analogue)
– ADSL
– Cable internet
Communication hardware
• 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
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Switches, hubs
Repeaters, bridges
Routers
Wireless Access Points
File Servers
Network Interface Cards
More details in the Networks-Hardware PPT.
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
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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
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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)
Slots
GENERAL PURPOSE
Oldest – ISA and EISA
Newer – PCI
Newest – PCI Express
VIDEO CARDS
Older – AGP
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
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
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#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
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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)
IT APPLICATIONS SLIDESHOWS
By Mark Kelly
[email protected]
vceit.com
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