Royal Latin School

Spec Coverage: a) Explain the advantages of networking stand-alone computers into a local area network e) Describe the differences between a local area network and a wide area network such as the internet 

Local Area Network (LAN)  When the computers are fairly close to one another say, in a single office or two buildings that are separated by a road, they can be joined together either by cables or wireless means.  These computers then form a Local Area Network (LAN).  Once the computers are connected together into a LAN, many people (users) can share and use the same resources at the same time. They can share files, software, hard disks and peripherals such as a printer or CD-ROM. Users can also use the LAN to communicate with each other by . Data can be transmitted very quickly between networked computers.  To log onto a LAN, you usually need a user name and password. The user name identifies you to the file server so that it can 'serve' you the correct files. The password ensures that the user name really does belong to you.

a – explain the advantages of networking stand- alone computers into a local area network

Network computers?  A computer connected to a network is known as a 'work-station' Sharing hardware peripherals  At home, your computer might be connected to its own printer and scanner. This works well as you are the only person who will be using them. Much of the time though, they probably aren't being used and just lie idle. A computer which isn't connected to a network is known as a 'stand-alone'

a – explain the advantages of networking stand-alone computers into a local area network  In a school or an office, it would cost a lot of money for every computer to have its own printer and for the majority of the time, like your printer at home, it wouldn't be used.  By joining computers together to form a network, they are able to share one printer. This means that more money can be spent buying a better quality printer and that the printer is being used much more of the time.

a – explain the advantages of networking stand-alone computers into a local area network Sharing files  Networks allow you to share files with other users. You might have a folder at school called the 'shared area' or something similar. This is often where teachers might put documents or resources that they want you to use during the lesson. All students can open these resources and save them to their own area, but they usually can't alter the original copies in the shared area.  In many organisations, some workers might have permission to alter the documents in the shared area. This means that they can work collaboratively on a project or document and each person can update it as required.

a – explain the advantages of networking stand-alone computers into a local area network Sharing printers and other peripheral devices is a great reason for networking computers. However, there are plenty of other reasons. Log onto a workstation  At home, when you save your work, its usually saved onto the hard disk of the computer that you are actually working on. When you want to access this document again, you can only open it by using the same computer. If you try to use your brother's computer in the next room, you usually won't be able to see the document.  Instead, in a networked workstation situation everyone's work is saved on a file server. When you log onto the network, you type in your user name and password. Your user name tells the network who you are and the file server finds your files and makes them available to you.

Advantages cont. Central backups  You know how important it is to backup your files regularly. Imagine how much work it would be for the network manager if they had to backup every students' work individually each day. Computer networks make this an easy task. All of the files and folders can be backed up centrally from the file server each evening after the school closes. Installation of software  Most schools have hundreds of computers. It would be a very time consuming task if the network manager had to install a new piece of software onto every computer on the network. Instead, a lot of software can be installed centrally just once and then made available to each workstation.  This also means that software licences can be checked to ensure that all of the software installed on the network is a legal copy.

Advantages Cont. Virus checks  Anti-virus software can also be run centrally and can check every workstation on the network at the same time. Security  If you had to save your documents onto one of the computer's hard drives in the school, not only would you be tied to always having to log onto that computer, it would mean that anyone else going onto that computer could also see all of your work and perhaps alter, delete or copy it. With a network, each person can only see their own files and folders, so this helps to keep your work safe.

Advantages Cont.  Networks can be managed. This means a network manager is able through the network software to control who can access the network, when they can access it, and what files and software and hardware they are allowed to use.  An audit trail of each user can be built up so that projects can be more efficiently costed, for example, by keeping track of what printouts are done in connection with what project.  Users, knowing that their activities are being monitored, will also be encouraged to stay on- task and not waste the organisation's time!

Disadvantages of Networking Viruses  If a virus is introduced to the network, either intentionally or unintentionally, it will rapidly spread around all of the workstations and could start to cause havoc to peoples' files or to the efficient working of the network. Network failure  If the file server fails then no-one on the network can access any files or folders. This means that nobody can do any work. For an organisation, this would be extremely costly and disruptive.  If a cable, hub or switch on the network fails, this would mean that any computers connected to that part of the network couldn't be used to access network resources. They could still be used as individual, stand-alone machines.

Disadvantages Cont. Slow service  As more users log onto the network and request files, send things to be printed and open more software applications, the network can start to slow down. There is only a limited amount of bandwidth and the more data that is travelling around the network, the slower things become. Cost  Building a network isn't cheap. Every machine has to be connected to the network either by physical cables or perhaps by wireless technology. Every workstation needs a network interface card to enable it to be connected to the network. Other hardware such as hubs, switches and routers are often needed.

Disadvantages Cont. Expert support required  Networks need constant monitoring to ensure that the performance is maintained and that all of the components are working properly. This requires specialist staff such as network managers and technicians who will spend all of their time ensuring that the network works efficiently whenever you need to use it. These staff add a large cost to running a network, but without them, things would start to fail.

Wide Area Network (WAN) Many modern companies have offices, shops or factories in various locations around the country, and for large corporations, across the world. Even though staff work in different places, they often need to be able to access the same information no matter where they are. It would not be possible to connect computers in different buildings together using the LAN cables. Imagine how many roads would need to be dug up to lay cables between a building in London and one in Birmingham. Computers on LANs in one building can be connected to computers on LANs in another building usually through the telephone system, often using a modem. They can also be connected via fibre optic cables, microwave links or satellite. By linking LANs together, the network is no longer local to one building, it is now spread over a wide area. It is known as a Wide Area Network (WAN).