<programming> A common form of distributed system in which software is split between server tasks and client tasks. A client sends requests to a server, according to some protocol, asking for information or action, and the server responds. This is analogous to a customer (client) who sends an order (request) on an order form to a supplier (server) who despatches the goods and an invoice (response). The order form and invoice are part of the "protocol" used to communicate in this case. There may be either one centralised server or several distributed ones. This model allows clients and servers to be placed independently on nodes in a network, possibly on different hardware and operating systems appropriate to their function, e.g. fast server/cheap client. Examples are the name-server/name-resolver relationship in DNS, the file-server/file-client relationship in NFS and the screen server/client application split in the {X Window System}. Usenet newsgroup: news:comp.client-server. ["The Essential Client/Server Survival Guide", 2nd edition, 1996]. (1998-01-25)

client-server

client-server

Client-server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate over a computer network on separate hardware, but both client and server may reside in the same system.

Client Server Runtime Subsystem, or csrss.exe, is a component of the Windows NT family of operating systems that provides the user mode side of the Win32 subsystem and is included in Windows NT 3.

In computing, a client is a piece of computer hardware 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.

In computing, a server is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called "clients". This architecture is called the client–server model.

<networking> Opposite of "thin client". (1996-12-08)

In computer networking, a rich client (also called heavy, fat or thick client) is a computer (a "client" in client–server network architecture) that typically provides rich functionality independent of the central server. This kind of computer was originally known as just a "client" or "thick client," in contrast with "thin client", which describes a computer heavily dependent on a server's applications.

In computer networking, a thin client is a simple (low-performance) computer that has been optimized for establishing a remote connection with a server-based computing environment. They are sometimes known as network computers, or in their simplest form as zero clients. The server does most of the work, which can include launching software programs, performing calculations, and storing data. This contrasts with a rich client or a conventional personal computer; the former is also intended for working in a client–server model but has significant local processing power, while the latter aims to perform its function mostly locally.

Thin clients occur as components of a broader computing infrastructure, where many clients share their computations with a server or server farm. The server-side infrastructure uses cloud computing software such as application virtualization, hosted shared desktop (HSD) or desktop virtualization (VDI). This combination forms what is known as a cloud-based system, where desktop resources are centralized at one or more data centers. The benefits of centralization are hardware resource optimization, reduced software maintenance, and improved security.

• Example of hardware resource optimization: Cabling, bussing and I/O can be minimized while idle memory and processing power can be applied to user sessions that most need it.
• Example of reduced software maintenance: Software patching and operating system (OS) migrations can be applied, tested and activated for all users in one instance to accelerate roll-out and improve administrative efficiency.
• Example of improved security: Software assets are centralized and easily fire-walled, monitored and protected. Sensitive data is uncompromised in cases of desktop loss or theft.

Thin client hardware generally supports common peripherals, such as keyboards, mice, monitors, jacks for sound peripherals, and open ports for USB devices (e.g., printer, flash drive, webcam). Some thin clients include (legacy) serial or parallel ports to support older devices, such as receipt printers, scales or time clocks. Thin client software typically consists of a graphical user interface (GUI), cloud access agents (e.g., RDP, ICA, PCoIP), a local web browser, terminal emulators (in some cases), and a basic set of local utilities.