TOPIC 6.4: NETWORKING

NETWORKS

• A network is a series of computer systems that are linked together so that they are able to share computing power or storage facilities.
• The link may be between computers in the same building or between computers in different parts of the country or even in different parts of the world.
• All the common data such as the disk. A dedicated file server monitors and controls the network and while it is performing this important task, it is not available to be used as a normal workstation.

LOCAL AREA NETWORKS

• Local area networks (LANs) are confined to a small area. Usually this small area is within a single building although it need not be confined to just a single office.
• Sometimes LANs spread through several buildings on the same site.
• Messages can be sent between the terminals and this is very useful for sending memos between offices.

WIDE AREA NETWORKS

• Wide area networks (WANs) cover a wide geographical area.
• For instance, banks and building societies have their main computers situated in one place with connections made by telephone wires to all the various branches.
• Using WANs, computers may be linked together in different countries using satellites, microwaves or telecommunication links.
• In practice, LANs are often connected to WANs via a special gateway.
• Using a gateway any computer system can be accessed provided that it is connected to one of the many communication systems in use.

ADVANTAGES OF NETWORKING

1. Expensive peripheral devices such as laser printers and scanners can be shared between users.

2. Messages can be sent between users on the same site with LANs or anywhere in the world with WANs.

3. All users can access the same files on this avoids having to duplicate information.

4. Network software can be purchased which is often cheaper than buying an individual package for each machine.

5. It is possible to access data or programs from any terminal or workstation.

6. Data and software can be stored centrally, which makes them easier to maintain and back up.

7. Users can easily be prevented from accessing those files that are not needed for their job. This means that someone in the accounts department would not, for instance, be able to access the personnel files.

DISADVANTAGES OF NETWORKING

1. If a WAN is used, sophisticated equipment is needed and the rental of telecommunication links makes it very expensive.

2. A loss in the ability to transmit data for even a short time can cause havoc, with tasks having to be performed manually.

3. File security is more important with networks, especially if they are connected to the public telephone system. for instance, if a virus were to get onto a network then it could affect all the networked terminals.

4. Wiring can be expensive both to buy and to install. Wiring has to be sunk to avoid it trailing across a floor where it would be dangerous.

5. In a type of network called a file-server network all the programs and data is stored on a main computer called a server. If this server breaks down, the whole network becomes unusable.

6. Networks are temperamental; they need an experienced person (a network manager) to keep them running successfully. Network managers are usually well paid and this adds to the cost of network.

RESOURCE:

S.Doyle, [Information Systems for you, 3rd. Edition], Nelson Thornes Ltd., 2001.