In computing, a client is a piece of

computer hardware Computer hardware includes the physical parts of a computer, such as the computer case, case, central processing unit (CPU), Random-access memory, random access memory (RAM), Computer monitor, monitor, Computer mouse, mouse, Computer keyboard, ...

or software that accesses a service made available by a server as part of the client–server model of computer networks. The server is often (but not always) on another computer system, in which case the client accesses the service by way of a network. A client is a computer or a program that, as part of its operation, relies on sending a request to another program or a computer hardware or software that accesses a service made available by a server (which may or may not be located on another computer). For example, web browsers are clients that connect to

web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...

s and retrieve web pages for display. Email clients retrieve email from mail servers. Online chat uses a variety of clients, which vary on the chat protocol being used.

Multiplayer video game A multiplayer video game is a video game in which more than one person can play in the same game environment at the same time, either locally on the same computing system (couch co-op), on different computing systems via a local area network, or ...

s or online video games may run as a client on each computer. The term "client" may also be applied to computers or devices that run the client software or users that use the client software. A client is part of a client–server model, which is still used today. Clients and servers may be computer programs run on the same machine and connect via inter-process communication techniques. Combined with Internet sockets, programs may connect to a service operating on a possibly remote system through the Internet protocol suite. Servers wait for potential clients to initiate connections that they may accept. The term was first applied to

device A device is usually a constructed tool. Device may also refer to: Technology Computing * Device, a colloquial term encompassing desktops, laptops, tablets, smartphones, etc. * Device file, an interface of a device driver * Peripheral, any devi ...

s that were not capable of running their own stand-alone programs, but could interact with remote computers via a network. These computer terminals were clients of the time-sharing

mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...

Types

In one classification, client computers and devices are either thick clients, thin clients, or diskless nodes.

Thick

A ''thick client'', also known as a ''rich client'' or ''fat client'', is a client that performs the bulk of any data processing operations itself, and does not necessarily rely on the server. The personal computer is a common example of a fat client, because of its relatively large set of features and capabilities and its light reliance upon a server. For example, a computer running an art program (such as Krita or

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) that ultimately shares the result of its work on a network is a thick client. A computer that runs almost entirely as a standalone machine save to send or receive files via a network is by a standard called a workstation.

Thin

A ''thin client'' is a minimal sort of client. Thin ''clients'' use the resources of the host computer. A thin client generally only presents processed data provided by an

application server An application server is a server that hosts applications or software that delivers a business application through a communication protocol. An application server framework is a service layer model. It includes software components available to a ...

, which performs the bulk of any required data processing. A device using web application (such as Office Web Apps) is a thin client.

Diskless node

A ''diskless node'' is a mixture of the above two client models. Similar to a fat client, it processes locally, but relies on the server for storing persistent data. This approach offers features from both the fat client (multimedia support, high performance) and the thin client (high manageability, flexibility). A device running an online version of the video game Diablo III is an example of diskless node.

References

{{Download managers Peer-to-peer computing