Server

• A server computer, sometimes called an enterprise server, is a computer system that provides essential services across a network.
• It provide services to private users inside a large organization or to public users in the internet.
• The type of services provided by a server computer depends on the type of server computer that is used.
• Servers come in all sizes from x86-based PCs to IBM mainframes.
• In large companies, servers often reside in racks in the datacenter, and all access is via their network connections

Types of server computer
1)Application server 

• An application server is a server that is designed for or dedicated to running specific applications.
• At its most basic, an application server might be used to run one application.
• Another possibility is that an application server is used to run certain kinds of applications.
• For example, a large company might have several word processing or spreadsheet or desktop publishing programs, and all of those applications might reside on one server.
• Another kind of application server is one that runs an operating system. This is more old-fashioned, but it is still used.

2) Web server

• Web servers are computers on the internet that host websites, serving pages to viewers upon request.
• Every web server has a unique address so that other computers connected to the internet know where to find it on the vast network.
• The more powerful the server, the faster it can serve up website pages.
• Slower, smaller servers may result in frustrating lag time for viewers.
• High traffic can also slow servers that are not powerful enough to handle high volumes of data exchange

 

3) E-mail server

• An e-mail server is a computer within in a network that works as a virtual post office.
• It usually consists of:

1)A storage area where e-mail is stored for local users

2)A set of user definable rules which determine how the mail server should react to the destination of a specific message

3) A database of user accounts that the mail server recognizes and will deal with locally

4)Communications modules which are the components that actually handle the transfer of messages to and from other mail servers and email clients.

  

4) Mainframe/High-end server


• A mainframe server is a very large and powerful server used to control a large portion of a enterprise.

• Mainframes are sometimes called "Enterprise Servers" or "Super Computers."

• Mainframe servers include an array of CPU's, memory, and disk drives.

• Companies like IBM, Sun Microsystems, HP, SGI, and Cray produce some of the most powerful mainframe computers on the planet.

• Most of these machines run some type of proprietary Operating System. For instance, the Cray SV1 system runs an OS called UNICOS.


• It is used as:

1) A file server for a very large organization (this usually means the government or government contracted organizations).

2) Large universities and research organizations also use mainframes for various projects.

3) Cancer researchers use clusters of IBM servers to perform linear algebra and other mathematical operations needed to complete research.

4) Sun Microsystems lease their enterprise servers to certain groups such as animators and graphics producers to perform rendering.


•While prices vary, and used mainframes are significantly cheaper, they run from around $5,000 (around RM20,000) to well in the millions.

5) Midframe/Midrange server

• Midrange server refers to computers that are more powerful and capable than personal computers but less powerful and capable than mainframe server.

• Midrange server have been sold to small to medium-sized businesses as their main computer and to larger enterprises for branch or department-level operations.

• Makers of popular midrange server lines include Hewlett-Packard, IBM, and Sun Microsystems.