WEEK 2 & 3

Subject: Information and Computer Technology�

Term: 1st Term

Class: Primary 6

Topic: Computer networks

Behavioral Objectives:

At the end of the lesson, Pupils should be able to:

�i). Define computer net- computer net-

�ii). List the types of computer

�INSTRUCTIONAL MATERIALS:

A functional computer system

Reference Materials

Lagos state scheme of work,

Online information

Relevant materials

Pupils textbook

Behavioral Objectives: pupils are familiar with the topic in their previous classes.

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CONTENT

A computer network

A computer network is a group of two or more computers connected together so that they can share resources like hardware, software and data. Computers in a network can communicate with one another.

Computer network is the interconnection of computers and other telecommunication devices together for the purpose of sharing resources. There sources that can be shared in such interconnections include: files and folders, programs, printers, hard disk, processor etc.

When computers are interconnected through a central computer, communication link between users become easier. This could enable them to exchange information freely between each other, and also allow a common use of components.�

In a network environment, when there is a centrally located computer to which all other computers are connected, it is called HOSTCOMPUTER or SERVER. The other computers connected to such a computer are called TERMINALS or WORKSTATION.

IMPORTANCE OF COMPUTER NETWORK

Computer network is important for the following reasons.

1. It enables users to access files or programs from another computer without carrying disk.
2. It enable computer to print documents on a printer attached to another computer
3. It enables users to be able to send messages by using electronic mail (E-mail).
4. It can make users to gain easy access to the internet.

Types of hardware for computer network

There are three types of hardware needed for computer network for the purpose of data communication. They are:

1. Central processor.

There must be computer otherwise called the HOST Computer that must have a central processor.

2. Terminals or work stations.

These are the other computers that are connected to a server or central computer.

3. Communication channels

Communication channels refer to things that could link different systems together. Examples are: cables, telephones, satellite stations, etc.

Types of networks

The two types of computer networks are:

1 Local Area Networks (LAN); and

2 Wide Area Networks (WAN)

Local Area Networks

LAN consists of a collection of microcomputers that� can share peripherals and information. They can also communicate with each other on the network.

Microcomputers in a LAN are usually in the same building or a school. Each microcomputer in a LAN can work both as an independent personal computer running its own software and as a workstation. A LAN has a network server. This runs the network operating system which allows resources to be shared with other computers on the network. Each� computer on a LAN is known as a client. The devices shared by a LAN are printers, hard disk drives, disk drives, CD-ROM drives, modems and fax machines.

Advantages of a LAN

1������ Software and data files can be shared by many users.

2 It is usually cheaper to buy one copy of a software application and pay the license fee for several machines, than to buy individual packages for each computer.

3 Users can work together on a single document from different parts of the network (though not at the same time).

4 Users can communicate with other users on the network using e-mail.

Wide Area Networks (WANs)

A WAN connects networks across a large geographical area such as a city, state or country. Information can be transmitted using special high-speed telephone lines, microwave links, satellite links or a combination of all these. WANs are used in universities, research centers, companies and banks, so that information can be shared across a country or across many countries.

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Metropolitan Area Network (MAN)

This type of network is mostly used by Radio and Television stations. In this case, computers are interconnected within a wider geographical location such as within a town, city or state for the purpose of data communication.

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ASSESSMENT AND EVALUATION

i). Define computer net- computer net-

�ii). List the types of computer

WRAP-UP (CONCLUSION): Teacher goes over the topic once again for better understanding

Activity

1 What is the difference between a server and a client in a LAN.

2 Mention 5 organizations where LANs are used.

3 Mention 5 organizations where WANs are used.