Input and Output Devices

Input Devices

Ways of putting data INTO a computer

Keyboard

Mouse

Microphone

Scanner

Keyboards

Normal

Concept

Ergonomic

Keyboards

Advantages

Fast data entry

Proven technology

Easy to use

Disadvantages

Can be difficult for people with disabilities

Relatively slow

Big

Numeric Keypads

Keypads to enter numbers

Used at ATMs, POS

Advantages

Small and easy to use

Disadvantages

Keys may be too small for some people

No text entry

Mice

Used to point at stuff on screen

Cordless, optical mice are normal now

Advantages

Easy and intuitive to use

Disadvantages

Can be difficult for people with poor motor skills

Tracker Ball

Advantages

Easier to use than normal mouse with poor motor skills

More accurate positioning of screen pointer

Disadvantages

Not standard issue – Training may be required

Bigger than a normal mouse

Joystick

Advantages

Intuitive control

Uses 3 dimensions

Disadvantages

Cant do the job of a mouse

Touch Screens

Advantages

Don’t need a mouse

Very easy to use

Disadvantages

Limited options

RSI

Need to be cleaned regularly

Magnetic Stripe Readers

Reads the black stripe on a credit card

Advantages

Fast Data entry – Faster than typing

Secure – no-one can see the data

Disadvantages

Black Stripe needs to be undamaged

Card needs to be near card reader

Smart Card Reader

Different from stripe reader

Card does not get swiped

Reads a chip in the car

Advantages

Can be used instead of money

Disadvantages

More difficult to replace

Input Devices(2)

Chip and Pin Readers

Owner has to enter a secret number

Advantages

More secure – signatures are easy to copy

Disadvantages

Must not let anyone know the PIN

Scanners

Scan documents – produce a digital copy

Advantages

Images can be stored in the computer

Can email the images

Disadvantages

Trade-off between quality and file size

Barcode Readers

Instead of typing the number – read the stripes

Advantages

Much faster – more accurate than typing the number

Disadvantages

Expensive to buy the equipment.

OMR devices

Optical Mark Recognition

Advantages

Can mark multiple choice exam papers quickly

Disadvantages

Forms need to be carefully designed

Forms need to be filled in accurately

OCR Readers

Optical Character Recognition – Cheques, Passports

Advantages

Can scan a whole paper document and create a Word document – much quicker than typing

Disadvantages

Cant read handwriting

90% accurate

MICR Devices

Magnetic Ink Character Recognition

Used to process Cheques

Advantages

Error free, no handwriting

Disadvantages

Can only read certain characters

Digital Camera

Advantages

Easier to use than traditional cameras

Cheaper – no film to process

Do it all at home

Disadvantage

Requires ICT skills

Loss of artistry

Webcams

Advantages

Cheap

Allow easy access to internet communications

Disadvantages

Security

Poor picture

Microphones

Used to record sound

Advantages

They can enable you to record sound

Disadvantages

They don’t make ice-cream

Sensors

Smoke, heat, pressure, humidity, speed……

Advantages

More accurate than a person taking the reading

24X7

Safer than manually reading the temperature at the bottom of an erupting volcano

Disadvantages

Bad sensor – bad results

Graphics Tablet

Advantages

Makes computer drawing easier

More accurate than a mouse

Disadvantages

Expensive

Light Pen

You can point to stuff on a monitor

Advantages

You can point to stuff on a monitor

Disadvantages

Software can be slow – lag

Not accurate

Old technology

Output devices

Output devices Screen or monitor

Printer

Speakers

Multimedia projector

Plotter

Control device (e.g., robot arm, motor, light, etc.)

Screens/monitors

LCD (liquid crystal display)

CRT (cathode ray tube)

Used to output information that is not needed permanently

CRT Monitors

Cathode Ray Tube monitors

Advantages

Better image than TFT

Wider viewing angle

Disadvantages

Very heavy

Use more power

TFT Monitors

Thin-film transistor Monitors.

Advantages

Thinner

Less energy than CRT

Disadvantages

Poorer image than CRT

Multimedia Projector

Can project computer output on a large screen.

Advantages

Can project computer output on a large screen.

Disadvantages

Expensive to buy

Fuzzy image

Difficult setup

Printers Used to output

information as hard copy (i.e. printed on paper)

Ink-jet printers – cheap to buy but expensive to run

Laser printers – more expensive to buy but cheaper to run

Dot matrix printers – ideal for multi-part printouts

Laser Printers

Fast, high quality, high volume print.

Advantages

Fast, high quality, high volume

Disadvantages

Expensive to buy

Inkjet Printers

Advantages

Cheap alternative to a laser printer with high quality

Disadvantages

Slower than Laser printer

3D Inkjet Printer

Uses inkjet technology to create 3D models.

Advantages

Save a lot of money creating prototypes

Disadvantages

Expensive to buy

Dot Matrix Printer

Advantages

Can be used in dusty environments

Uses continuous stationery

Disadvantages

Poor print quality

Very noisy

Speakers Used to output the sound/music

after processing/storage by the computer

Plotters Used to output scale drawings (e.g., maps

and plans)

Can print on much larger paper (e.g., A0)

Used by architects, engineers, patternmakers, etc.

AdvantagesVery large, very highest quality outputDisadvantagesVery expensive to buyVery, very slow

Actuators Used to control devices

Can turn devices such as switches, motors, pumps, etc., on and off

They respond to signals sent by the computer

Motors, buzzers, heaters and lights/lamps

Motors:

Used to turn valves

Can turn watering systems on/off

Can close/open windows

Can turn drums of washing machines

Motors, buzzers, heaters and lights/lamps

Buzzers:

Act as warning signs

Used to tell when a process has finished

Washing machines make a buzz when they have finished

Motors, buzzers, heaters and lights/lampsHeaters:

Can be controlled bysignals from a computer

Can be found in cookers, washing machines,dishwashers,greenhouses, etc.

Motors, buzzers, heaters and lights/lampsLights/lamps:

Can be used with sensors to turn lights on when light level falls

Can be used to provide artificial light in greenhouses

STORAGE DEVICESAND MEDIA

Storage Devices

Methods of access

Serial access (like a cassette tape)

Start at the beginning and read until you find your data.

Direct Access(cd or dvd)

Go straight to your data

Backup Storage Media

Magnetic

Optical

Solid State

ROM and RAM Used to hold data

(program instructions and data it is currently processing)

Stored in chips

Contents of memory are available immediately

Two types ROM and RAM

ROM (Read Only Memory)

Non volatile – does not lose contents when power is turned off

Contents cannot be altered by the user

Used to hold instructions needed to start the computer (i.e. the boot program)

RAM (Random Access Memory)

Temporary – the contents are continually changing

Volatile – loses contents when power is turned off

Contents can be altered by the user (i.e. it is read/write)

Stores data while the power is supplied

Backing/secondary storage devices and media

Used for the storage of data and programs not needed instantly by the computer

Used to take backups (i.e. copies) for security purposes

Data is usually backed up on Magnetic Tape or CD or DVD

Memory stick/pen drives/USB drives Small and portable

Large storage for size

Very reliable

Can easily be lost

Slow transfer rate\

Connections can wear out

Magnetic fixed hard disk drives

Advantages

Very high storage capacity

Very high access speed

Very high transfer rate (i.e. speed of reading/copying data)

Most computers come with one

Disadvantages

Easily Damaged and not portable

Portable hard drivesAdvantages

Can be removed from the computer

Useful for backup copies

Useful for transferring files between computers

Usually attached via a USB port

Disadvantages

Easily Damaged

Magnetic tapesAdvantages

Used for backing up large amounts of data

Huge storage capacity

Takes time for data to be found on a tape so not much use except for backup

Disadvantages

Serial Access (slow)

Easily Damaged

Optical drives Use removable media (i.e. CD or

DVD)

Can be used for backups

DVD used for films

CD used for music or software

Blu-ray used as an alternative to DVD as it has a much larger storage capacity

CD drives/mediaCD ROM(Compact disk read only memory):

used mainly for transfer of software

data can only be read

storage capacity of 700 Mb

data transfer speeds lower than for a hard diskCD RW (CD Rewritable):

allows data to be stored over and over again

smaller transfer rate than a hard drive

not as robust as a hard drive

CD drives/media continued

CD R (CD Recordable) Can only be recorded onto once Can be used for archive versions of data

DVD drives/mediaDVD-ROM

Can only be read

Higher storage capacity compared to CDs

Used for movies, multimedia programs, etc.

Drives can also read CDs

DVD drives/mediaDVD RAM Allows repeated storage like hard disk Fast transfer rate Quite expensive compared with other

methods

DVD R Can only be recorded onto once Ideal for TV recordings where you do not

want to record over them

DVD drives/media continuedDVD+RW Are read/write Sometimes called DVD

burners Ideal for data that needs

continual updating

Storage Devices

Blu-Ray Discs

Advantages Much higher storage capacity than DVD Used to store high definition video

Disadvantages

Expensive

Need Blu Ray drive to read them

Storage Devices

DVD-RAM

Advantages

Allow reading and writing SIMULTANEOUSLY

Used in satellite recorders

Disadvantages

Relatively expensive

Not as compatible as DVD

Solid state backingstorage/memory

Is the smallest form of memory

No moving parts so very robust

Flash memory card drives and cards

Thin cards used in digital cameras

Can be used in MP3 players

Storage Devices

Flash Memory Cards

EEPROMs – Electrically Eraseable Programmable Read Only Memory

Advantages

Very small so very portable

Robust

Disadvantages

Expensive

Solid state backingstorage/memory

Consists of:

Memory sticks/pen drives

Flash memory cards

Computernetworks

What is a computer network?

A network is two or more computers that are linked together so that they are able to share resources.

Resources which can beshared include

Hardware - printers, scanners, storage, etc.

Software – need only be installed on one computer

Data (e.g. database files)

An Internet connection

Network Types

LAN – Local Area Network

Inside a building

WAN – Wide Area Network

Between countries

LANs and WANs

Local area networks:

Confined to a small area

Usually located in a singlebuilding

Use cable, wireless, infra-redand microwave links which are usually owned by the organization

Less expensive to build as equipment is owned by the organization so no rental of lines and equipment needed

Wide area networks:

• Cover a wide geographical area (e.g. between cities, countries and even continents) in lots of different buildings, etc.

• Uses more expensive telecommunication links that are supplied by telecommunication companies

• More expensive to build as sophisticated communication systems are used and rental of lines and equipment needed

WLAN Stands for wireless local

area network

Is a LAN where all the devices on the network communicate wirelessly

Advantages

A network without wires

Disadvantages

Security (viruses, hackers)

Interference

Wi Fi

Connecting without wires to a network

e.g. In a café

Bluetooth (mobile phone)

WAN via a wireless router

Network topology Is the way the devices are

arranged in a network

In a wired network, it shows how the computers are connected together

In a wireless network it shows how the computers communicate with each other

Network topologiesThe three main network topologies are:

Ring

Bus

Star

Tree

The Ring Topologies

Advantages

Easy to set up

Fast

Disadvantages

Any fault and whole network is dead

The bus topology A backbone cable is usually

used

Advantages

A small amount of cable is needed

Simple to install

Easy to add extra devices

Disadvantages

Slow for larger networks

Reliance on the backbone cable

The star topology Uses a central connection point

This can be a server or a hub/switch

Advantages

Easy to add extra computers without disturbing the network

Disadvantages

They use a lot of wire

They depend on the centraldevice

Fault tolerant

The tree topology Combines bus and star

topologies

Advantages

Good for widely spread networks

Disadvantages

If a bus cable failed, the computers in a single star could still communicate

Not suitable for small networks as it uses too much cable

Network Devices

Modems (modulate demodulate)

Translates analog to digital, digital to analog

Used to connect computers to networks across dial-up(not digital) telephone lines

Networks

Network Traffic

All data in a network is sent as PACKETS.

All communication is broken down to packets.

Each packet contains a source address, destination address and the data.

All network devices in the world have a unique MAC address.

Network devicesA hub:

is used to join computers in a network

allows the connection of cables

allows the sharing of files and Internet access

Network Devices

Network Hubs

Connect multiple devices to one network connection

HUBNETWORKCONNECTION

SERVER

A hub has no intelligence

Network devicesA switch:

is a similar device to a hub but more intelligent

can look at a packet of data to decide where it should go

reduces the number of packets of data on a network which speeds the network up

Network Devices

Network Switch

Connect multiple devices to one network connection

SwitchNETWORKCONNECTION

SERVER

A switch has intelligence

Network devicesA router:

can be wired or wireless

is used to join several networks together

is often used to connect several computers in the home to the Internet

Network devices A network interface

card:

prepares data for sending over the network

sends the data

controls the flow of data

Network Devices

Network Bridge

Makes a connection between two LANs.

Packets are sent to the relevant LAN

All devices on each LAN see all packets.

Accounts HUB

Marketing HUB

Sales HUB

Router

Only relevant packets are routed to each device.

HTTP Proxy Servers

Server between the internet and a LAN.

All internet traffic goes through the Proxy Server.

Emails and web searches are filtered

Performs virus checking

Proxy Server

The Internet

All QP Computers

Authentication

Ensuring only authorised people access the network Username/passwords

Biometrics

Digital signatures

This is a special code used to check that electronic media (e.g. Emails) are really from the person they say they are from

Encryption

Data being transported across a network is encrypted at the source and decrypted at the destination using a key. Hackers cannot steal the data.

Encrypt data using key

Encrypted Data

Decrypt using same key.

Methods of Communication

Network Communcation

Networking computers and other devices allow improved communication between people using services such as:

1.Fax

2.Email

3.Teleconferencing/Video Conferencing

Fax

A fax machine scans paper documents and converts them into digital format.

The digital version is then converted into analogue format and sent over an ordinary telephone line to another fax machine.

The fax machine at the receiving end converts the analogue information back into digital format and reproduces an exact hard copy of the original document.

Fax – advantages…

Unlike emails, faxes do not spread viruses

Faxes cannot be hacked

Faxed signed documents are legally acceptable.

Fax - disadvantages…

Faxes are usually printed in areas that are accessible by others

Printer jams waste time

The receivers fax machine might not be on or out of paper

Information sent is a hard copy and therefore cannot be editted.

E-mail Used to send messages from one computer to

another

Can be sent between computers on a local area network (LAN) or between computers on the Internet

Email – advantages… Some advantages of e-mail:

Arrives at its destination in at most a few hours

Send and receive e-mail anywhere in the world, at any time

One e-mail message can be sent to a group of people

Registered e-mail can be sent

Can be cheaper than sending mail through the post

Can attach a file

E-mail - disadvantages Some workers receive

so many e-mails that they are unable to answer them all

Computer viruses are often sent by e-mail

Can send junk mail just as with conventional post

Video/Tele Conferencing

The use of a computer to send sound and video images from one computer to another in real time.

Video/Tele Conferencing

• Input/Output Devices needed:• Microphones to capture speech• Headphones or speakers to hear the speech• A web cam is needed to capture images of

themselves• A monitor/screen is used to view the video

images

Advantages of Videoconferencing

You can communicate with other people over long distances and see them as well as hear them

Videoconferencing is more personal than just a telephone call

Businesses can use videoconferencing to hold meetings in which many people can be involved

There is less need for people to travel

Disadvantages of videoconferencing

The hardware and software needed are very expensive

Not many people have videoconferencing systems

ISDN lines are needed which are expensive to set-up and use

There is no substitute for a face-to-face meeting.

Data types

Data types Logical/Boolean

Alphanumeric/text

Numeric (real and integer)

Date

A database is made up of tables

Tables are made up from records

Records are made up from fields

Fields have different data types

Data typesLogical/Boolean:

Can have only one of two values

Examples include: true/false, 1 or 0, Yes or No

Alphanumeric text:

Alphanumeric refers to letters, numbers and all other characters you see on the keyboard

Text is just the letters on the keyboard

Data types

Numeric (real and integer)

Real numbers contain numbers after the decimal point

Integers are whole numbers which can be positive, negative or zero

Data typesDates:

There are lots of different ways of representing a date

Examples include:dd/mm/yy,mm/dd/yy,yyyy-mm-dd

Some important database terms

Field – an item of data. Surname would be a field.

Record – the detail relating to a single thing or person. A record consists of fields.

File – a collection of related records.

Table – used to hold data with each row (other than the first) representing a record and the columns representing fields.

More important termsKey field:

A piece of data in a database that is unique to a particular record

In a school database a pupil number would be unique and therefore could be used as the key field

Tables Consist of rows

and columns

The first row contains the field names

Following rows contain the records

Columns contain database fields

Relational databases Data is stored in

more than one table

Tables are linked

Most commercial databases are relational databases

Foreign key is a field of one table which is also the key field of another

The problems with flat-file systems

Data redundancy – data is duplicated so more data needs to be entered than is needed

When a record is deleted then lots of data which may still be useful is deleted

The advantages of relational databases

Time is saved by not having to type as much data

Entering less data means fewer typing errors

Data redundancy is reduced

Systems analysis and designVALIDATION AND VERIFICATION

Valid data Data that is valid is allowable

Valid data has to obey certain rules

Data can be incorrect yet still be valid

Data can be valid and incorrect

Example:

A person has a date of birth 19/12/87

A user enters it incorrectly as 19/12/78

Both are valid as dates

Yet one is incorrect

Two techniques for reducing errors

Verification

Validation

Verification Checks that errors are not

introduced by the user during typing

Checks data entered is the same as on a source document (e.g., order form, application form, etc.)

Two methods of verification

Visual comparison – checking what has been typed in against the source of the data

Double entry of data – two people enter the same data – only if both sets of data are the same will it be accepted

Validation checks include

Data type checks – is data entered the right type for the field (e.g., letters are not entered into a numeric field)?

Presence checks – has a field been left empty?

Length and format checks – is data of the right length and the right combination of characters for a field (e.g., code FF019J has length 6 characters with first two letters, the next three numbers and the last a letter)?

Boolean checks – data is either: True or False, Y or N

Consistency checks – checks to see if the data in one field is consistent with the data in another field

Check digits

Added to important numbers such as bank account numbers, International Standard Book Numbers (ISBNs).

Added at the end of the block of digits

Used in a calculation using all the digits to check that all the digits have been entered correctly

Keeping data safeand secure

Software copyright theftCopyright is the right given to

software developers to protect them against having their work copied.

Software copyright Software being copied or given to

others

Using the name of copyrighted software without permission

Using the software on a network of more computers than you have paid for

Software being copied, amended and then passed off as your own

Computer viruses Install anti-virus software

Do not open email fileattachments unless youknow who they are from

Do not allow anyone toattach portable drivesor memory sticks withoutscanning them for viruses first

Do not load illegal games/software/music as these often contain viruses

Keeping data safe and secure

Passwords and usernames/user-IDs

Levels of access: only certain staff can access very personal details (e.g., medical records)

Firewalls – to prevent hackers

Encryption – to prevent unauthorized access

Use of anti-virus software – to ensure viruses do not enter the computer system

Keeping hackers out Hacking is the process of

accessing a computer system without permission

Most hackers use the Internet to hack into networks

http://us.fotolia.com/id/6457669

Protecting against hackers using a firewall

Looks at the data coming in from the Internet (i.e. the grey arrows)

If it is allowable it lets it through (i.e. the green arrows)

If not it is rejected by the firewall (i.e. the red wall shown here)

In this way it stops hackers

Protecting data from unauthorized access

Use usernames (user-IDs) and passwords

Use encryption when data is stored or transmitted (e.g. over the Internet)

Users must remember to log off when away from their computer

Protecting data from unauthorized accessUse physical methods to prevent access to computers or computer room such as:

Keypads to gain access to rooms

Biometric access to rooms and computers using fingerprinting or retinal scanning

Encryption Scrambles data

before sending or storing data

Used when banking or credit card details are sent over the Internet

If data is intercepted or stolen, it cannot be understood

The Effects of Using ICT

Social Divide

On one side – those who have the technology

On the other side – those who do not

Employment

Technology leads to unemployment ?

Robots can do many dangerous manual tasks:

Paint sprayingAssembly line construction

Employment

Technology creates unemployment?

Automated Warehouse

No people

Employment

Technology causes unemployment?

Printing was slow, highly skilled and used very nasty chemicals.

Employment

Technology causes unemployment?

Now printing uses software requiring no special skills and uses no nasty chemicals

Employment

Technology creates jobs

People are needed to design, build and program the robots

Printers re-train to use publishing software

Software and hardware needs to be designed and created to run the automated warehouse

There is always a net gain of jobs when new technology is introduced.

Effects of introducing new technology

Retraining to use the new technology – e.g. printers

Machines now do the dirty, unpleasant and dangerous jobs

Skilled jobs become unskilled – e.g. printers

Fewer repetitive, manual jobs

Advantages to Companies

Reduced labour costs

Higher productivity – robots don’t need breaks

Greater consistency in the quality of work – e.g. every car is the same

Microprocessor

What are Microprocessors?

Microprocessors in the Home

Microprocessors in the Workplace

Microprocessors in Everyday Life

Advantages

More leisure time as the devices do the work

People can meet other people while the dishwasher is on

People are becoming more technology-aware

DVD players are plugged into the internet

Disadvantages

People become too dependent on technology

TV dinners – unhealthy, convenience food

People become lazy

Society becomes more wasteful of energy

Technology illiterate people get left behind

Information from the Internet

Can you trust it?

NO!

Quality of Internet Information

ReliabilityUndesirability of certain

websitesSecurity issues (personal

and national)Other issues

Reliability of Information

Web info is more up-to-date than books and can be easily updated

Search engines, e.g.

Make it very easy to find information

However….

Information on the Internet can be:

Unreliable

Inaccurate

Not up-to-date

Biased

As there is no checking process.

Undesirability of certain websites

There is always a risk of coming across undesirable websites

Some weblinks may take you to undesirable websites

Security risks are high

Who decides what is undesirable?

Security Issues

Viruses

Phishing – Fraud by email – tempting you to go to a website and give away personal information

Phishing Example

Pharming

Fraud where users are re-directed to a fraudulent website usually by a virus.

Panix - In January of 2005, someone fraudulently changed the DNS address for the domain panix.com, a New York State Internet service provider.

Ebay (Germany) - In September 2004, a teenager in Germany managed to hijack the domain for eBay.de.

SPAM

Unsolicited email

We all get them. Get rich quick, get a green card, Viagra etc………………….

Some ISPs filter them out. Some mail systems have facilities to do your own filtering.

SpywareSoftware which gathers information from your computer.

Like a virus but its purpose is to steal credit card details, email lists or use webcams and broadcast on the internet.

Cookies

Not biscuits

When I log onto the Amazon website it displays my name. A cookie is used.

Amazon creates a cookie on my machine which the website reads from.

Is a “Cookie” spyware??

Use of Cookies

Cookies are very small

Websites use them to display targeted advertising e.g. latest Blu-Ray discs

Cookies enable a website to know if you have used their website before.

Cookies are easily removed from your computer.

If a website can create a cookie, it can create anything.

Effect of ICT on Society

Employment Over the years, the introduction of ICT

has affected employment. Key areas are:

Manufacturing

Warehousing

Other labour intensive areas

Manufacturing Many tasks in manufacturing have now been

automated with robots that are controlled by computers.

For example, most cars are now mostly constructed using robots. The robots can screw and weld parts together, lift heavy objects easily and paint the car body.

Warehousing

This is where items on an order list can be collected automatically by special robots. The humans then just have to send the order to the customer.

Labour Intensive Work Other work can also be done by

machines. A good example is printing newspapers and magazines. This used to be a very manual job but can now be automated with machines.

Advantages of using Robots and other Machines

Productivity is increased – this means that more work can be done in a shorter time

You don’t have to pay the robot wages

They do not need to take breaks

There is also less chance of human errors

The work is consistent – the quality is always the same

It is safer to use robots for dangerous heavy work

Disadvantages of robots and other machines

Robots and large manufacturing machines are expensive to buy in the first place

De-skilled workforce – since some of the highly skilled jobs are now done by robots and other machines, the jobs that are left for people to do require less skills and qualifications

Increased unemployment

Online shopping and banking

What is it? This is where you visit a special website (like

Amazon) in order to buy items. You search for the item you like, click ‘buy’ and then enter your delivery address and your credit card details. After a short time the item you bought is delivered to your house.

Online shopping and banking

Advantages You don’t have to leave your house to do it so

you save time and money travelling

There are a wide range of products because you can get them from all over the world

The products are cheaper because the company selling them does not have to pay for a shop, so they save money on rent, heating, lighting, staff etc

You can shop at any time because the website is available 24/7

Online shopping and banking Disadvantages

Fraud – it is possible (although unlikely) that your credit card details could be stolen and then used by someone else to buy other things. It is unlikely because on most websites the information is encrypted which means that it is converted to a special code that only the customers computer can understand

Online shopping and banking

Disadvantages You might become lazy or lonely because of a

lack of social interaction with other people

There could be an increase in the health risks associated with using computers

You cannot try out the product before you buy it

You have to have a computer and internet connection

Online Banking What is it?

This is a service provided by banks to allow people to work with their bank accounts using an internet website.

Because they deal with money and personal details, online bank websites need to be secure so they are always encrypted. Also, users have to put in a username, password and often another secret code to log in.

Online Banking Advantages

Online banks have the same type of advantages as online shops like no need to travel, saves time and fuel etc

It is also available 24/7

You can get up-to-the-minute information about your account

Online Banking Disadvantages

Same type of disadvantages as with online shopping

Security is particularly important as the website deals with lots of money and so extra login details are normally required etc

Effects on BusinessCustomers using online shopping and

banking also has an effect on businesses and companies. They can save on the costs of staff and

buildings for their shops/branches

Over the internet they have access to more customers

They do have to pay to set the online sites up

They might have to employ or train more staff to do other jobs like deliveries and fixing the website

The effects of using ICTINTERNET SHOPPING

Internet/online shopping and searching for products on websites

Many people search for and order services and products using the Internet

Online stores have databases of their goods and services which you can access

You can browse or search for a specific thing

Internet/online shopping Purchasing goods and services using

the Internet

Customers browse online catalogues

They add goods to their virtual shopping basket/trolley

They go to the checkout

They then enter their card (debit or credit) details and other details, which are encrypted for security reasons

Advantages of online shopping to customers

Disadvantages of online shopping to customers

Advantages of online shopping to the store

Disadvantages of online shopping to the store

Online booking services Low cost airlines and ease of

booking mean many people book flights and hotels direct

Can get impartial reports from others about resorts and hotels

Can book car rental

Advantages of booking online

Book from the comfort of your home

More time to look for holidays than when at a travel agent

Make savings when booking direct because no travel agent commission to pay

Read reports of people who have been on the same holiday that we intend to book

Arrange our own travel and accommodation

Find out about the resort before you go

Disadvantages of booking online

You have to enter credit/debit card details and these may not be kept safe

People could hack into the site and know you were away and burgle your house

There is no personal service like at a high street travel agent

You could easily enter the wrong information and book the wrong flights

Verification of bookings You are responsible for

entering booking details

You need to carefully verify data entered

This is done by a visual check (i.e., proof reading)

http://www.fotolia.com/id/14190586

Verification of a bookingNeed to check:

Credit card number entered is correct by comparing it again with the number on the actual card

Card expiry date

All the fields that should have data in them contain data

All the name and address details are correct – this is particularly important with flight tickets where the name on the passport has to match the name on the ticket

Passport numbers against the numbers on the actual passports

Internet Developments

Social Networking

A social network site allows you to post messages, upload pictures and stories on to your own personal page. This is then viewed by friends, family and colleagues.

Blogs

A Blog is a shortened form of the words Web Log.

A blog is a web site that is intended to offer and opinion or stories of what is happening to the author.

They started out

as personal diaries.

Wikis

Wikis are software that allow users to create and edit web pages. They are often known as web pages with an edit button.

Wikis should be treated with caution as anyone can edit them. One famous one is Wikipedia.

Digital Media Sharing Websites

Digital Media Sharing Websites allow you to upload and share videos on host websites.

An example of this is Youtube

Folksonomies

A way of adding a tag or classification to data of a particular type.

For example http://www.delicious.com/?view=hotlist

Expert Systems

What are they? An expert system is a computer system

that has been programmed with the knowledge of real human experts. It can then be given a situation and it can use logic to apply the knowledge as if it were a real expert.

For example, a computer chess game is a type of expert system. It has been programmed with moves that real chess players have made and it can use the rules of the game to choose the best move to make when it is it’s turn.

Examples Diagnosing illness (the system acts like a doctor

and has the knowledge of expert doctors programmed into it)

Mineral prospecting – this means looking for oil and other minerals like chalk, limestone and other rocky type things. Experts like geologists are used to program the system. The system can then help people to decide where to dig in order to find oil quickly.

Examples Other diagnosis like finding faults with car

engines or circuit boards (the system has the knowledge of mechanics and electronic engineers)

Chess games

Calculating tax – tax experts are used to program the system to help people to work out how much money they owe the government in tax

Why do we have them?

We have expert systems to help us. For example, knowledge that experts have can be saved in the system to be used even when they are not available (perhaps the experts are in a different place or even dead).

Why do we have them? They can save time – a doctor might be

able to diagnose an illness quicker because he or she can use the expert system to help. This would be quicker than looking up in a book.

They can also help people to do jobs in which they are not an expert. For example you might be able to find out what is wrong with your car by using an expert system.

How do they work? Expert systems follow these steps when they are

working: The ES asks the user questions about the problem.

These questions appear on the screen and the user types in the answers. This is the USER INTERFACE. The questions are about the symptoms of the problem.

The ES uses the answers. An INFERENCE ENGINE searches the KNOWLEDGE BASE using the RULE BASE.

The ES then suggests possible answer to the problem.

How do they work? For example, with diagnosing a fault

with a car, the user will type in things that the car does or does not do like ‘Does the car start?’

The ES will use the answers to the questions to perform its searches and then come up with a list of possible or suggested faults with the car.

Some Disadvantages It might be expensive to set up because it is

complicated and you need to get the real expert opinions.

It is not a person and so does not have common sense. This means that the person reading the suggestions (output) needs to check the answers are sensible in the situation.

You might need to be trained to use it, which could be expensive.

The ways in which ICT is used: Expert systems

Expert systems An ICT system that thinks and

behaves like a human expert in a certain field

These are systems that can be used to mimic a human expert

They use artificial intelligence to make decisions based on answers to questions

Components Knowledge base – set of knowledge

about a particular field/subject

Inference engine – a set of rules on which the decisions made by the system are based - these rules are applied to the knowledge base

User interface – the way the expert system communicates with the user - it presents the user with questions and allows them to type in the answers

Applications of expert systems

Doctors – for medical diagnosis

Geologists – to help them find the best place to look for minerals or oil

Accountants – for giving tax advice to individuals/companies

Car engine fault diagnosis

Medical diagnosis Enables a doctor to make an

accurate diagnosis

Gives a doctor the the knowledge and decision-making ability of a consultant in the field

Enables a patient to be put on the correct treatment without delay

Prospecting for minerals/oil Can take geological

information from maps to create the knowledge base

Use knowledge base and apply the rules in the inference engine to it

The user can enter locations using the user interface

The expert system will suggest the most likely places where minerals/oil could be found

Giving tax advice to companies/individuals Tax is complex

Companies and individuals want to legally minimize the tax they pay

Expert systems ask a series of question to arrive at an expert decision

Advantages and disadvantagesof expert systems

Advantages

Fewer mistakes – they do not forget things

Less time to train – human experts take a long time to train

More expertise than a single expert – systems based on expertise of many experts

Always asks the questions that a human expert may forget to ask

Cheaper – don’t have the wage costs of a human expert

Disadvantages

Fewer mistakes – they do not forget things

Less time to train – human experts take a long time to train

More expertise than a single expert – systems based on expertise of many experts

Always asks the questions that a human expert may forget to ask

Cheaper – don’t have the wage costs of a human expert

Systems analysis and designVALIDATION AND VERIFICATION

Valid data Data that is valid is allowable

Valid data has to obey certain rules

Data can be incorrect yet still be valid

Data can be valid and incorrect

Example:

A person has a date of birth 19/12/87

A user enters it incorrectly as 19/12/78

Both are valid as dates

Yet one is incorrect

Two techniques for reducing errors

Verification

Validation

Verification Checks that errors are not

introduced by the user during typing

Checks data entered is the same as on a source document (e.g., order form, application form, etc.)

Two methods of verification

Visual comparison – checking what has been typed in against the source of the data

Double entry of data – two people enter the same data – only if both sets of data are the same will it be accepted

Validation checks include

Data type checks – is data entered the right type for the field (e.g., letters are not entered into a numeric field)?

Presence checks – has a field been left empty?

Length and format checks – is data of the right length and the right combination of characters for a field (e.g., code FF019J has length 6 characters with first two letters, the next three numbers and the last a letter)?

Boolean checks – data is either: True or False, Y or N

Consistency checks – checks to see if the data in one field is consistent with the data in another field

Check digits

Added to important numbers such as bank account numbers, International Standard Book Numbers (ISBNs).

Added at the end of the block of digits

Used in a calculation using all the digits to check that all the digits have been entered correctly

Systems Analysis

We Are Learning To

Explore the different stages of the Systems Lifecycle

Identify and describe in detail what happens at each of the different stages.

Systems Analysis What is it?

Systems Analysis and Design is the process we use in business to make sure that when we do a new project for a customer we deliver the correct thing at the end.

To do this we have to: investigate the problem

ask the customer questions

design the solution to the problem using the answers to the questions and the investigation to help us get it right

In ICT we are talking about designing new computer programs or systems.

The process involves several different stages.

Analysis

This is where we (the systems analyst) do two things. We find out exactly how the old or

existing system works. This is because we can’t replace it with a new system if we don’t know how the old one works.

We find out how the customer wants to improve on their existing system. Normally someone who wants to buy a new computer system is in some way unhappy with the old one.

Analysis

How do we do this? There are 4 ways that we perform analysis, they

are Observation, Questionnaires, Interviews and Looking at existing documents. We need to know about all of these.

Analysis

Observation – This is where the systems analyst simply watches people doing their work using the old system.

Advantages You can see exactly what is going on

It does not cost much money

The information is reliable

Disadvantages Some staff don’t like being watched and so they might be

uncomfortable. This means that they might not do everything in the normal way.

Analysis Questionnaires – This is where the systems analyst

creates a list of questions about the old system and gives them to many employees to answer.

Advantages Making questionnaires does not cost much money

The questions can be answered quite quickly: many people can give you their answers all at the same time.

The people answering the questions may not need to give their names (they are anonymous)

A computer can be used to check the answers

Disadvantages People might not take them seriously and give silly answers or not give in the

papers at all (if it is anonymous)

The questions are fixed – if you were with the person answering, you might think of another question to ask them based on their answer. With a questionnaire you cannot ask new questions like this

Analysis

Interviews – This is where the analyst has a face to face conversation with the customer to ask them about the old system and the way it works.

Advantages You can ask extra questions based on the answers given – the questions are

flexible

You can ask questions that have much longer answers than on a questionnaire to give in depth knowledge

Disadvantages It takes a long time as the analyst has to sit with each person individually

This makes it expensive too as it takes up a lot of the analyst’s time

Obviously, the person being interviewed cannot be anonymous

Analysis

Looking at existing paperwork – this is where the systems analyst collects examples of all the different printouts that come from the old system and then looks at them very closely.

Advantages There is some information that can only be collected in this way

It also gives the analyst information about how many prints the system produces

Disadvantages For looking in detail to be done properly, a lot of time must be taken

This means that it can be quite an expensive method of doing analysis

Design

This is where the person doing the design (could be the systems analyst or could be a new person - the system designer it depends on the size of the project), takes the results of the analysis and designs a new way of solving the problem. There are many things that need to be designed.

Data capture forms

Screen layouts for input screens

Output forms and reports

System Flow Charts

Design

Data capture forms

These are the paper forms that are used to gather the data that is to be input into the new system

Design

Screen layouts for input screens

These are the designs of the screen displays that users of the system will see and use

Design

Output forms and reports

When the computer is asked for information by the user, the screen display it shows is called an output form, and the way this form looks has to be designed.

The users can also ask the computer for printed output and these are called reports. The layout of the reports (i.e. The columns that are shown, the width of the columns, the column titles, the colour of the writing etc) all have to be designed.

Design

System Flow Charts

This is a description of how the system will work that uses special flow chart symbols (or shapes). Part of a flow chart might look like this:

Design

Select the hardware that is needed

The designer will also have to decide which type of computers will be needed for the new system. He or she will need to say how large the hard disks will need to be, how much memory the computer will need, how big the screen will be, the type of processors the computers will need etc.

Design

Select any software that is needed

As well as writing new programs (or applications) some projects can be completed by using software that already exists.

For example a person who needed to do the accounts for their business could use a spreadsheet package. So selecting software is also something a designer might do. Also doing the new project might mean the a new operating system is required (e.g. a newer version of Windows).

Design Design the test plan

Every type of computer system will need to be tested to check that it works properly.

To do the testing properly to make sure everything is tested, there must be a plan that says which tests are needed and what we expect the result to be.

For each of the tests, the designer has to decide on which data is to be typed in as part of the test.

There are 3 types of test data: Normal

Extreme

Abnormal

Design Design the test plan

Normal – Normal data is data that we expect the system to allow. For example, if there were a box to type in the year group, any number between 1 and 13 should be allowed. If any of these values is not allowed then the test has failed.

Extreme – Extreme data is the two values at the upper and lower limits of the range so in the example of year groups, the extreme data would be 1 and 13. They should be allowed by the system.

Abnormal – Abnormal data is data that the system should not allow at all. In our example any number greater than 13 or less than 1 should not be allowed. The number 25 would be abnormal data in this case and should be rejected by the system.

Design

Verification and Validation Rules Another thing the designer must design is the verification

and validation rules.

These are the checks that the system uses on the data that is entered.

The tests in the above section are designed to test whether the validation rules are working properly.

Design

Verification and Validation Rules Validation

This is where the computer checks to see if the data that is entered is valid.

Valid means that the data is allowable and sensible.

IT CANNOT CHECK THAT THE DATA IS CORRECT, because it doesn’t already know the correct values.

There are many types of validation rule (see sheet), but the main ones are Length Check, Range Check and Presence Check.

Design

Verification and Validation Rules Verification

This is a process that can be used to check if information is correct when it is entered into a computer system. There are two ways of doing this:

Double entry – this is where the computer asks the user to enter the same data twice. The computer compares the two and if they are the same it says the data is correct or incorrect.

Visual Check – often data entered into a computer is copied from somewhere else like a piece of paper, for example an application form on paper will be copied into a computer system. A visual check is where a person compares the information on the original paper with the information that has been entered. When errors are spotted they are corrected.

Development

This is where the system that has been designed is made. Computer programmers (the people that write programs) will create any databases that are needed, the screen layouts, the reports, all the calculations and the verification and validation routines.

Testing

Once the development (or parts of the development) is finished, they will be tested using the test plan that was designed in the design stage.

Sometimes when the system is very large, it will be tested in smaller pieces before being put together.

Otherwise the tests would be very long and confusing.

Implementation

This is where the completed and tested system is finally given to the customer.

There are 4 ways of doing this: Direct

Parallel

Pilot

Phased.

Each of them has their own advantages and disadvantages (see sheet).

This is sometimes called changeover as the customer has to change over from the old system to the new one.