Server System

A server is a system (software and suitable computer hardware) that responds to requests across a computer network to provide, or help to provide, a network service. Servers can be run on a dedicated computer, which is also often referred to as "the server", but many networked computers are capable of hosting servers. In many cases, a computer can provide several services and have several servers running. Servers operate within a client-server architecture, servers are computer programs running to serve the requests of other programs, the clients. Thus, the server performs some task on behalf of clients.

The clients typically connect to the server through the network but may run on the same computer. In the context of Internet Protocol (IP) networking, a server is a program that operates as a socket listener.[1] Servers often provide essential services across a network, either to private users inside a large organization or to public users via the Internet. Typical computing servers are database server, file server, mail server, print server, web server, gaming server, or some other kind of server. Numerous systems use this client / server networking model including Web sites and email services. An alternative model, peer-to-peer networking enables all computers to act as either a server or client as needed.

Operating System for Server.
Server-oriented operating systems tend to have certain features that make them more suitable for the server environment, such as GUI not available or optional ability to reconfigure and update both hardware and software to some extent without restart, advanced backup facilities to permit regular and frequent online backups of critical data, transparent data transfer between different volumes or devices, flexible and advanced networking capabilities, automation capabilities such as daemons in UNIX and services in Windows tight system security, with advanced user, resource, data, and memory protection. Server-oriented operating systems can, in many cases, interact with hardware sensors to detect conditions such as overheating, processor and disk failure, and consequently alert an operator or take remedial measures themselves. Because servers must supply a restricted range of services to perhaps many users while a desktop computer must carry out a wide range of functions required by its user, the requirements of an operating system for a server are different from those of a desktop machine. While it is possible for an operating system to make a machine both provide services and respond quickly to the requirements of a user, it is common to use different operating systems on servers and desktop machines. Some operating systems are supplied in both server and desktop versions with similar user interface. Windows and Mac OS X server operating systems are deployed on a minority of servers, as are other proprietary mainframe operating systems, such as z/OS. The dominant operating systems among servers are UNIX-based open source distributions, such as those based on Linux and FreeBSD.[citation needed] The rise of the microprocessor-based server was facilitated by the development of Unix to run on the x86 microprocessor architecture. The Microsoft Windows family of operating systems also runs on x86 hardware and, since Windows NT, have been available in versions suitable for server use. While the role of server and desktop operating systems remains distinct, improvements in the reliability of both hardware and operating systems have blurred the distinction between the two classes. Today, many desktop and server operating systems share similar code bases, differing mostly in configuration. The shift towards web applications and middleware platforms has also lessened the demand for specialist application servers.