thin client

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.

<networking> A simple client program or hardware device which relies on most of the function of the system being in the server. Gopher clients, for example, are very thin; they are stateless and are not required to know how to interpret and display objects much more complex than menus and plain text. Gopher servers, on the other hand, can search databases and provide gateways to other services. By the mid-1990s, the model of decentralised computing where each user has his own full-featured and independent microcomputer, seemed to have displaced a centralised model in which multiple users use thin clients (e.g. {dumb terminals}) to work on a shared minicomputer or mainframe server. Networked personal computers typically operate as "fat clients", often providing everything except some file storage and printing locally. By 1996, reintroduction of thin clients is being proposed, especially for LAN-type environments (see the {cycle of reincarnation}). The main expected benefit of this is ease of maintenance: with fat clients, especially those suffering from the poor networking support of Microsoft {operating systems}, installing a new application for everyone is likely to mean having to physically go to every user's workstation to install the application, or having to modify client-side configuration options; whereas with thin clients the maintenance tasks are centralised on the server and so need only be done once. Also, by virtue of their simplicity, thin clients generally have fewer hardware demands, and are less open to being screwed up by ambitious lusers. Never one to miss a bandwagon, Microsoft bought up {Insignia Solutions, Inc.}'s "NTRIGUE" Windows remote-access product and combined it with Windows NT version 4 to allow thin clients (either hardware or software) to communicate with applications running under on a server machine under {Windows Terminal Server} in the same way as X had done for Unix decades before. (1999-02-01)