ICT

What is a network?

A computer network is a number of computers linked together to allow them to share resources. Networked computers can share hardwarehardware: the physical components of a computer, softwaresoftware: a general term used to describe an application or a program and datadata: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information.

Most computer networks have at least one server. A server is a powerful computer that provides one or more services to a network and its users. For example, file storage and emailemail: electronic mail - a message written or typed on a computer and sent electronically rather than by post.

LANs and WANs

There are two main types of network:

  1. Local Area Network (LAN)
  2. Wide Area Network (WAN)

LAN

A LAN covers a small area such as one site or building, eg a school or a college.

Shows multiple workstations connected in a circle, including a server.

LAN - Local Area Network

WAN

A WAN covers a large geographical area. Most WANs are made from several LANs connected together.

Shows a WAN, made from several smaller networks, which could be local area networks (LAN). Each of the smaller networks has it's own server and multiple workstations connected.

WAN - Wide Area Network

  • The InternetInternet: a global network connecting millions of computers is a WAN.
  • A network of bank cash dispensers is a WAN.
  • A school network is usually a LAN.
  • LANs are often connected to WANs, for example a school network could be connected to the Internet.
  • WANs can be connected together using the Internet, leased lines or satellite links.

Advantages and disadvantages of networks

Advantages

  • Sharing devices such as printers saves money.
  • Site (softwaresoftware: a general term used to describe an application or a program) licences are likely to be cheaper than buying several standalone licences.
  • Files can easily be shared between users.
  • Networknetwork: a group of interconnected computers users can communicate by emailemail: electronic mail - a message written or typed on a computer and sent electronically rather than by post and instant messengerinstant messenger: an application that allows users to send instant messages (text) to one another.
  • Security is good - users cannot see other users' files unlike on stand-alone machines.
  • Datadata: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information is easy to backupbackup: to copy data onto a separate storage device in case the original device should fail, be damaged or the data stored on it get corrupted as all the data is stored on the file serverfile server: a networked computer that provides large amounts of shared storage, it can be accessed by workstations on the same network.

Disadvantages

  • Purchasing the network cabling and file servers can be expensive.
  • Managing a large network is complicated, requires training and a network manager usually needs to be employed.
  • If the file server breaks down the files on the file server become inaccessible. Email might still work if it is on a separate server. The computers can still be used but are isolated.
  • Virusesvirus: a small program written to cause harm to a computer can spread to other computers throughout a computer network.
  • There is a danger of hackinghacking: to gain unauthorised access to a computer, particularly with wide area networks. Security procedures are needed to prevent such abuse, eg a firewallfirewall: an application that prevents unauthorised connections to and from the Internet.

Sample question on networks

Question

A school with 20 stand alone PCs is considering networking them together and adding a file server.

Consider four possible benefits of doing this.

toggle answer

Answer
  1. All 20 computers will be able to print to a single printer. Without the networknetwork: a group of interconnected computers you would need 20 printers, or each student would have to wait until the computer with the printer attached was free.
  2. All 20 computers will be able to share an Internet connectionInternet connection: a computer's or another internet-enabled device's connection to the Internet, giving all the students access to the InternetInternet: a global network connecting millions of computers.
  3. Students can have their own space on the file serverfile server: a networked computer that provides large amounts of shared storage, it can be accessed by workstations on the same network, improving security when compared to storing the files locally on each computer.
  4. The file server can be backed up to tape every night keeping the students' documents safe.

Examiner's comments:

This answer would get full marks as 4 benefits are described.

Make sure you list the correct number of points asked for - this question asked for four benefits. You would have been given only 2 marks if you'd only listed two benefits, eg security and the ability to share a printer.

A benefit always offers an advantage of somekind. For example, the ability to share a single printer is a benefit because only one printer needs to be purchased, this saves the school money.

Now try a Test Bite

Back to Revision Bite