Servers

In some small networks, every machine is equally likely to have a resource that another machine needs to use.

For example a small home network may be set up like this:

There are files stored on each computer. One machine is linked to the scanner, whilst another is linked to a printer. The game machine is linked to the internet, which all three machines can use.

This is fine for small networks as the number of requests to use a resource is not going to be too high.

Printer Server.

But now imagine there are a dozen computers on the network and each one needs to print out a document every few minutes. The machine that is connected to the printer is going to be tied up most of the time.

In this case it makes sense to allocate a machine exclusively to service printer requests. This machine is called a 'printer server'

File server.

Consider a network of a dozen computers. There could be thousands of files scattered across each machine. Two problems arise:

a) how do you find the file you need?

b) how do you back up your data to keep it safe?

The solution is to keep all your files on one computer. This machine is called the 'file server'.

Advantages:

	Files are simple to find
	Files are easily shared
	User computers can be switched off without any problem of a file becoming unavailable.
	Data is easily backed up.

Database server.

Many companies rely on a central store of information to run their operations. Information such as sales and stock data is usually kept in a database.

Very often a machine will be dedicated to run a specific database. This machine is called a 'database server'

Advantages:

	All data is available from anywhere in the network
	A specially designed computer can be selected to run the database e.g lots of memory.
	Database is easily backed up.

Other kinds of server.

A server is any machine that provides a service for other users on the network.

Common services include:

	Email server
	Internet Proxy server
	Intranet server.

The email server will provide all the usual facilities such as address books, spam filtering and so on.

Quite often, staff want to use the same website over and over again. The Internet Proxy server will store a local copy of often-used web pages to speed up access and to reduce bandwidth consumption (which costs money).

Many companies run their own private internal web services. This is called an Intranet and is run from the Intranet server.