Fat client
Encyclopedia
A fat client is a computer (client
) in client–server architecture or networks that typically provides rich functionality independent of the central server
. Originally known as just a "client" or "thick client" the name is contrasted to thin client
, which describes a computer heavily dependent on a server's applications.
A fat client still requires at least periodic connection to a network or central server, but is often characterised by the ability to perform many functions without that connection. In contrast, a thin client generally does as little processing as possible and relies on accessing the server each time input data needs to be processed or validated.
.
The characteristics of the user interface often force the decision on a designer. For instance, a drawing package could choose to download an initial image from a server and allow all edits to be made locally, returning the revised drawing to the server upon completion. This would require a thick client and might be characterised by a long time to start and stop (while a whole complex drawing was transferred) but quick to edit.
Conversely, a thin client could download just the visible parts of the drawing at the beginning and send each change back to the server to update the drawing. This might be characterised by a short start-up time, but a tediously slow editing process.
VDUs, and thick clients were generally not used until the increase in PC usage. The original driving force for thin client computing was often cost; at a time when CRT terminals and PCs were relatively expensive, the thin-client–server architecture enabled the ability to deploy the desktop computing experience to many users. As PC prices decreased, combined with a drop in software licensing costs, thick client–server architectures became more attractive. For users, the thick client device provided a more-responsive platform and often an improved Graphical User Interface (GUI)
than could be achieved in a thin client environment. In more recent years, the Internet has tended to drive the thin client model despite the prodigious processing power that a modern PC has available.
applications, for example the X Window System
, Citrix products and Microsoft
's Terminal Services
, which effectively allow applications to run on a centrally-hosted virtual PC and copy keystrokes and screen images between the local PC and the virtual PC. Ironically, these ultra-thin clients are often used to make available complex or data-hungry applications which have been implemented as thick clients but where the true client is hosted very near to the network server.
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....
) in client–server architecture or networks that typically provides rich functionality independent of the central server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
. Originally known as just a "client" or "thick client" the name is contrasted to thin client
Thin client
A thin client is a computer or a computer program which depends heavily on some other computer to fulfill its traditional computational roles. This stands in contrast to the traditional fat client, a computer designed to take on these roles by itself...
, which describes a computer heavily dependent on a server's applications.
A fat client still requires at least periodic connection to a network or central server, but is often characterised by the ability to perform many functions without that connection. In contrast, a thin client generally does as little processing as possible and relies on accessing the server each time input data needs to be processed or validated.
Introduction
In designing a client–server application, a decision is to be made as to which parts of the task should be executed on the client, and which on the server. This decision can crucially affect the cost of clients and servers, the robustness and security of the application as a whole, and the flexibility of the design to later modification or portingPorting
In computer science, porting is the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed...
.
The characteristics of the user interface often force the decision on a designer. For instance, a drawing package could choose to download an initial image from a server and allow all edits to be made locally, returning the revised drawing to the server upon completion. This would require a thick client and might be characterised by a long time to start and stop (while a whole complex drawing was transferred) but quick to edit.
Conversely, a thin client could download just the visible parts of the drawing at the beginning and send each change back to the server to update the drawing. This might be characterised by a short start-up time, but a tediously slow editing process.
History
The original server clients were simple text display terminals including WyseWyse
Wyse Technology is an American company that is a leading manufacturer in Cloud Client Computing. Products include thin client hardware and software as well as desktop virtualization. Other products include cloud software-supporting desktop computers, laptops, and mobile devices...
VDUs, and thick clients were generally not used until the increase in PC usage. The original driving force for thin client computing was often cost; at a time when CRT terminals and PCs were relatively expensive, the thin-client–server architecture enabled the ability to deploy the desktop computing experience to many users. As PC prices decreased, combined with a drop in software licensing costs, thick client–server architectures became more attractive. For users, the thick client device provided a more-responsive platform and often an improved Graphical User Interface (GUI)
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
than could be achieved in a thin client environment. In more recent years, the Internet has tended to drive the thin client model despite the prodigious processing power that a modern PC has available.
Centrally hosted thick client applications
Probably the thinnest clients (sometimes called "Ultra Thin") are remote desktopRemote Desktop
Remote Desktop may refer to:* Remote desktop software** Apple Remote Desktop** Remote Desktop Services** Remote Desktop Protocol* Desktop sharing...
applications, for example the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
, Citrix products and Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's Terminal Services
Terminal Services
Remote Desktop Services in Windows Server 2008 R2, formerly known as Terminal Services in Windows Server 2008 and previous versions, is one of the components of Microsoft Windows that allows a user to access applications and data on a remote computer over a network, using the Remote Desktop...
, which effectively allow applications to run on a centrally-hosted virtual PC and copy keystrokes and screen images between the local PC and the virtual PC. Ironically, these ultra-thin clients are often used to make available complex or data-hungry applications which have been implemented as thick clients but where the true client is hosted very near to the network server.
Advantages of thick clients
- Fewer server requirements. A thick client server does not require as high a level of performance as a thin client server (since the thick clients themselves do much of the application processing). This results in drastically cheaper servers.
- Offline working. Thick clients have advantages in that a constant connection to the central server is often not required.
- Better multimedia performance. Thick clients have advantages in multimedia-rich applications that would be bandwidth intensive if fully served. For example, thick clients are well suited for video gaming.
- More flexibility. On some operating systems software products are designed for personal computers that have their own local resources. Running this software in a thin client environment can be difficult.
- Using existing infrastructure. As many people now have very fast local PCs, they already have the infrastructure to run thick clients at no extra cost.
- Higher server capacity. The more work that is carried out by the client, the less the server needs to do, increasing the number of users each server can support.