1. LO3 – Understand Business IT Systems
3.1 – Types of Servers

2. Providing a central, common file storage area
Types of servers
Servers are special, powerful computers that provide services’ to the client computers on the network. These services might include:
Providing a central, common file storage area
Sharing hardware such as printers
Controlling who can or can’t have access the network
Sharing Internet connections
Servers are built to be very reliable. This means that they are much more expensive that normal computers.
The server is a key device within a client-server network. There may be only one server on the network, for example in a simple office set-up. Or there may be dozens on the network of a large corporation.
A server is a fairly powerful computer dedicated to provide some service to the client computers.
A client server network has a powerful computer known as a server which provides all of the services required on the network. These can include directing traffic around the network, managing disk drives and network peripherals such as printers and scanners.
The 'client' part of the network are the workstations that people log onto in order to use the network facilities.
This is the type of network most often used in middle to large organisations. In larger set-ups there may be several servers on the network, each one dedicated to a task or service. For instance there could be:
A print server which handles all of the print jobs required by network users
An server which provides a centralised service for all network users
File servers. There may be several file servers to provide plenty of storage capacity
An authentication server which handles all log-in and security measures
A web server to provide an internal intranet service
A client-Server Network
More information here

3. File Server

4. A file server will store and manage files on the network.
Normally the file server will be mapped to a drive letter such as "W:" so as far as you are concerned it is just the same as using your hard disk. You are able to create, copy, move, delete and rename files.
The server administrator often sets up a storage space for your own private use where your own files are kept. They may also set up a shared area, where the files can be seen and used by anyone in your shared group.
Most file servers will have a quota system in place to prevent someone or some department hogging more storage than they should have.
The file server administrator is also able to set the permission levels for each file and folder. For instance there may be a set of files that can only be read - no one can over-write or delete them.Your own files will be set to read-write.
There could be many file servers on a large network, perhaps each one dedicated to a specific department within the company for instance a 'Finance' file server and a 'Production' file server.

5. Database Server

6. Database
Some application servers may have a specialised role as database servers which manage databases with multiple users. These servers are database-architecture independent – the server will manage all activities, whether it is a relational database, flat file or object-oriented.
A database server is a computer system that provides other computers with services related to accessing and retrieving data from a database. Access to the database server may occur via a "front end" running locally a user's machine or "back end" running on the database server itself, accessed by remote shell. After the information within the database is retrieved it is outputted to the user requesting the data.
Web Server
This handles the delivery of web pages and files linked to those web pages. A web server can sit on an Intranet so it remains private to those users. Or it can be connected to the Internet, in which case it will be handling one or more domain names.

7. Print Server

8. A print server is dedicated to handling and managing printing to a networked printer.
The print server does this by using a 'print queue' storage area sometimes called the print spooler.
As each client sends a 'print job' to the network printer it gets stored in the printer queue ready for its turn to get printed. If the owner of the job changes their mind, they are able to delete it from the spooler. The administrator is also able to manage the print spooler. For example a job may have a problem such as permanently waiting for 'letter' sized paper to be loaded into the printer when there isn't any. This stops all the jobs behind it and so the admin will delete it from the queue.

9. Application Server

10. Application Server - Installing an application on a single computer can take a long time. And if there are dozens of client computers then it will take a very long time. A more efficient approach in these circumstances is to deploy an application server.
An application server allows client computers to run licenced applications without needing to be installed locally.
Web Server - This handles the delivery of web pages and files linked to those web pages. A web server can sit on an Intranet so it remains private to those users. Or it can be connected to the Internet, in which case it will be handling one or more domain names.

11. Mail Server

12. Mail Server - Email today is a fundamental part of most organisations
Mail Server - today is a fundamental part of most organisations. The simplest approach is to use an online service for services. This will work, but an alternative is to deploy an server on the network. This will manage all aspects of - sending, receiving and storing s
For instance each employee can have a proper business address such as
Departments can be given a shared address such as that sales staff then manage.
With an server it is also simple to send broadcast message to every employee from senior management such as how the company is doing
Hypervisor - This is software written for a particular processor which manages different operating systems or copies of the same operating system on a single computer or computer system. It manages resources such as the processor, memory and devices so that each operating system not only receives the resources it needs but also prevents it clashing with the other operating systems.