A server a piece of computer hardware or software that gives other programs or devices, known as "clients," access to functionality. The client–server model is the name given to this architecture. Servers can perform computation for a client or share data or resources among multiple clients, two examples of functions that are referred to as services. A single client can use multiple servers same time and a single server can serve multiple clients at same time. A client process may connect to a server on a different device through a network or run on the same device. web servers, database servers, file servers, mail servers, game servers, print servers and application servers are all common types of servers.

The request response model is usually used to implement client server systems . A client sends a request to the server which takes some action and responds to the client with a result or acknowledgment typically. When a computer is called server-class hardware, it means that it is made to run servers. This frequently implies that it is more powerful and dependable than standard personal computers. on the other hand, large computing clusters may be made up of numerous relatively straightforward server components that can be replaced.