INFORMATION TECHNOLOGY

Term usage in information technology
A server is simply a computer that provides services or resources to other computers.[2]
Server is an adjective in the term server operating system. A server operating system is intended or better enabled to run server applications. The differences between the server version and the workstation version of an operating system vary. Sometimes the difference can be the removal of an arbitrary limit due to licensing, as in the case of Windows 2000, or it can be the addition of bundled applications as in Mac OS X Server. Some server applications (e.g. Microsoft IIS) impose arbitrary limits on the number of HTTP connections they will accept, depending on whether they are running under a server operating system or not.
A server computer (often called server for short) is a computer system that has been designated for running a specific server application. A computer that is designated for only one server application is often named for that application. For example, when the software Apache HTTP Server is used as the web server for a company's website, the computer running Apache is also called the web server. Server applications can be divided among server computers over an extreme range, depending upon the workload. Every server application can run concurrently on a single computer under light loading, but multiple server computers may be required for each application under a heavy load. Under medium loading, it is common to use one server computer per server application, in order to limit the amount of damage caused by failure of any single server computer or security breach of any single server application. Any server computer can also be used as a workstation, but it is avoided in practice, again to contain risk.
Server or server computer is also a designation for computer models intended for use in running server applications, often under heavy workloads, unattended, for an extended period of time. While any workstation computer can run server operating systems and server applications, a server computer usually has special features intended to make it more suitable. These features can include a faster CPU, faster and more plentiful RAM, and larger hard drives, but these traits are shared with high-end desktops. More obvious distinctions include redundancy in power supplies, network connections, and storage devices as well as modular design. Blade servers are an example of the latter and are often used in server farms.
The name server or server appliance also applies to network-connected computer appliances or "appliance hardware" that provide specific services for other clients on the network. Though the appliance is a server computer, loaded with a server operating system and running a server application, the user need not configure any of it — it is a black box that does a specific job. The simplest servers are most often sold as appliances, like switches, routers, gateways, and print servers.