ICT BLOGGER HOMEWORK EASTER

Networks

Networks can be made locally or gloabally. A  local network is called a LAN which stands for Locan Area Network.  A global network is called  WAN which stands for Wide Area Network
There are three types of network connections. Ring Bus and Star

A Bus Network






Advantages

The bus is simple, reliable in very small networks, easy to use, and easy to understand.

The bus requires the least amount of cable to connect the computers together and is therefore less expensive than other cabling arrangements.

It is easy to extend a bus. Two cables can be joined into one longer cable with a BNC barrel connector, making a longer cable and allowing more computers to join the network.

A repeater can also be used to extend a bus; a repeater boosts the signal and allows it to travel a longer distance.

Disadvantage

Only one computer at a time can send a message; therefore, the number of computers attached to a bus network can significantly affect the speed of the network. A computer must wait until the bus is free before it can transmit.




A Star Network

 

Each computer on a star network communicates with a central hub that resends the message either to all the computers (in abroadcast star network) or only to the destination computer (in a switched star network). The hub in a broadcast star network can be active or passive.

An active hub regenerates the electrical signal and sends it to all the computers connected to it. This type of hub is often called amultiport repeater.

Advantages

It is easy to modify and add new computers to a star network without disturbing the rest of the network. You simply run a new line from the computer to the central location and plug it into the hub. When the capacity of the central hub is exceeded, you can replace it with one that has a larger number of ports to plug lines into.

The center of a star network is a good place to diagnose network faults. Intelligent hubs (hubs with microprocessors that implement features in addition to repeating network signals) also provide for centralized monitoring and management of the network.

Single computer failures do not necessarily bring down the whole star network. The hub can detect a network fault and isolate the offending computer or network cable and allow the rest of the network to continue operating.

You can use several cable types in the same network with a hub that can accommodate multiple cable types.

 Disadvantages

If the central hub fails, the whole network fails to operate.

Many star networks require a device at the central point to rebroadcast or switch network traffic.

It costs more to cable a star network because all network cables must be pulled to one central point, requiring more cable than other networking topologies.

 A Ring Network




Every computer is connected to the next computer in the ring, and each retransmits what it receives from the previous computer. The messages flow around the ring in one direction. Since each computer retransmits what it receives, a ring is an active network and is not subject to the signal loss problems a bus experiences.



Advantages

Because every computer is given equal access to the token, no one computer can monopolize the network.

The fair sharing of the network allows the network to degrade gracefully (continue to function in a useful, if slower, manner rather than fail once capacity is exceeded) as more users are added.

Disadvantages

Failure of one computer on the ring can affect the whole network.

It is difficult to troubleshoot a ring network.

Adding or removing computers disrupts the network.

Generic Software

Generic software is software which many companies make an example of this is a word processor, a spread sheet sorftware and a powerpoint software.

Generic software include buttons and logos that can be easily recognised so that the use fo the button is clear even if the user has never used this specific software, an example of this would be the save icon as it is the same or very similar on all software.

Computer Misuse Act

Data stored electronically is easier to misuse; that software should not be copied without permission; the consequences of software piracy; that hacking can lead to corruption of data, either accidentally or on purpose.

Types of computer misuse

Misuse of computers and communications systems comes in several forms:

Hacking

Hacking is where an unauthorised person uses a network, Internet or modem connection to gain access past security passwords or other security to see data stored on another computer. Hackers sometimes use software hacking tools and often target, for example, particular sites on the Internet.

Data misuse and unauthorised transfer or copying

Copying and illegal transfer of data is very quick and easy using online computers and large storage devices such as hard disks, memory sticks and DVDs. Personal data, company research and written work, such as novels and textbooks, cannot be copied without the copyright holder's permission.

Copying and distributing copyrighted software, music and film

This includes copying music and movies with computer equipment and distributing it on the Internet without the copyright holder's permission. This is a widespread misuse of both computers and the Internet that breaks copyright regulations.

Email and chat room abuses

Internet services such as chat rooms and email have been the subject of many well-publicised cases of impersonation and deception where people who are online pretend to have a different identity. Chat rooms have been used to spread rumours about well known personalities. A growing area of abuse of the Internet is email spam, where millions of emails are sent to advertise both legal and illegal products and services.

Pornography

A lot of indecent material and pornography is available through the Internet and can be stored in electronic form. There have been several cases of material, which is classified as illegal, or which shows illegal acts, being found stored on computers followed by prosecutions for possession of the material.

Identity and financial abuses

This topic includes misuse of stolen or fictional credit card numbers to obtain goods or services on the Internet, and use of computers in financial frauds. These can range from complex well thought out deceptions to simple uses such as printing counterfeit money with colour printers.

Viruses

Viruses are relatively simple programs written by people and designed to cause nuisance or damage to computers or their files.

The Computer Misuse Act (1990)

This was passed by Parliament and made three new offences:

1. Accessing computer material without permission, eg looking at someone else's files.
2. Accessing computer material without permission with intent to commit further criminal offences, eg hacking into the bank's computer and wanting to increase the amount in your account.
3. Altering computer data without permission, eg writing a virus to destroy someone else's data, or actually changing the money in an account.

The Data Protection Act

This was introduced to regulate personal data. This helps to provide protection against the abuse of personal information. Find out more about the Data Protection Act.

Copyright

Copyright law

This provides protection to the owners of the copyright and covers the copying of written, musical, or film works using computers. FAST is the industry body which is against software theft. You can find out more about it in the Copyright section.
There have been cases where laws such as Copyright have been used to crack down on file sharing websites or individuals who store and illegally distribute copyrighted material, eg music. There is a massive problem with many people around the world obtaining copyrighted material illegally.

Weblogs + Social Networks

http://www.youtube.com/watch?v=6a_KF7TYKVc

What is social networking?

Social networking sites, while they include the ability to post written material to the web like blogs do, revolve much more around the ability of an individual to build a web "presence" and to create visible links with others in the network. What writing there is on a social networking site is often in computer slang, intended to be "different." These sites often allow the ability to place music, photo, and video content on the site, allowing the individual to showcase their likes and dislikes. A form of text messaging is often included as well, with a history of the messages appearing on the site. Again, all of the features of social networking sites are intended to create social interactions with others.