A2 ICT - Topic 2: The Internet

What is the Internet?

- Huge group of networks joined together and each of these networks consists of lots of smaller networks which means that the Internet consists of hardware

File Transfer Protocol (FTP)

- Used to transmit any type of file by a way in which the data is put into packages

- Can be used to download a file from a server via the Internet as well as uploading

- You are not limited by file size -> You can transfer big files whereas with emails you cannot

E-commerce

- Mainly used for buying goods like books and food shopping

Requirements needed to implement an interactive on-line shopping service - Trained staff for creating and maintaining website, electronic catalogue/database of stock, search facility, secure payment methods and database of customer orders

Advantages of E-commerce to Customers:

- 24/7 usage

- Don't need to travel

- Good for disabled people as it allows them to do their own shopping

Disadvantages of E-commerce to Customers:

- Can be cases of fraud

- Customers get worried about security with credit/debit cards

- Can't really see how good something is by a picture

Advantages of E-commerce to Businesses:

- Fewer staff are required, easy to change prices everyday, more cost-effective

Disadvantages of E-commerce to Businesses:

- Increased competition from abroad, delivery costs, reliance on third party delivery companies

On-line Databases:

- Users can access the same database

- Data is always up-to-date

- E-commerces systems use on-line databases which contain products, customer and order details

- Electronic data interchange is used by big retailers to automatically order goods from their suppliers

- The system performs ordering, checking and making payments, automatically without needing any paperwork

How to Access On-line Information

- Find way around the Internet via the URL (Uniform Resource Locator), following hyperlinks and using a search engine

How a Search Engine Works

- Lots of web pages stored

- Web browser called a web crawler or spider follows the links it can find and each webpage it comes across is analysed for content like key words. The index is stored in a database.

- Search engine examines the index for words and creates a list of webpages which match the closest

- The ones with greatest relevance will appear first

Web crawler -Program which automatically browses all webpages in a systematic manner and it does this so that it can produce an index that can be utilised by a search engine to allow quick searches

How webpages are added to search engine lists - Depends on search engine being used but generally a search engine will rank the webpages according to:

- most relevant match, most popular site, most authoritative site, ability of a company to pay for a higher ranking

Boolean Searches:

- Help save time as they narrow down a search

AND - If you type in 'USA AND flag' you will receive all the documents which contain both of the words -> Don't need to type the 'and'

OR -If you type in 'USA OR flag' you will receive all documents which contain the word USA, all the ones which contain the word flag and all the ones which contain both words

NOT - You can exclude information by using the word 'NOT'

Searching for an exact match - Put quotation marks to get an exact match, and if you want an actual quotation then you need to know the exact quote and put quotation marks around it

Choosing the information to use -Is it relevant for the purpose, is source reliable, is it accurate, is it unbiased, precise and appropriate for the intended audience?

Distributed Computing using the Internet:

- Can be used to solve the problem of analysing large amounts of data requiring lots of computer power which is very expensive

- Can be done using a few less powerful computers connected together using the Internet

- Some systems ask home users to contribute some of their computing resources

Advantages: Reduces cost, pass work to computers anywhere in the world via the Internet and improved performance

Disadvantages: Security problems

The SETI (Search for Extraterrestrial Intelligence project) - Purpose of it is to search for intelligent life outside the Earth and radio telescopes are used -> They pick up radio signals from outer space and if the signals were confined to a narrow range of frequencies then this would show extraterrestrial life -> Problems include background noise, and lots of computer power is required

Popular Power project: helping to develop flu vaccines - Helps to develop an influenza vaccine and the system made use of a computer model which modelled the human immune system and simulations were performed to see how different vaccines might perform -> Viruses mutate so vaccines may not work one year after

Cable access to the Internet:

Dialup Modem -Very slow and limits its use -> Uses a modem which changes digital signals into a series of sounds which are then passed along a telephone line and then the sound signal is changed back to a digital signal which the computer can understand at the other end

Broadband -Much faster so you can do more things like watching videos on-line and listening to on-line radio stations -> Advantages include that large multimedia files can be downloaded quickly, you can still use the phone whilst on-line and no time wasted trying to connect to the Internet -> Disadvantages include it's expensive and it may not be available in the area or country where you are

Mobile Access to the Internet - Laptops, PDAs and mobile phones can allow you to access e-mails and the Internet when you are travelling -> Advantages include you can do this anywhere, you can work more productively, you can work anywhere and you can make changes to plans easily -> Disadvantages include that you may feel you are never away from work, it can be expensive if accessed from a mobile phone, increased security risks, and there are several places where you cannot access these things