thinclient computing.ppt (Size: 555 KB / Downloads: 284)
A thin client network is a server based network in which the processing is done by the server rather than by the individual client machine's.
The term thin is derived from the small or Ëœthinâ„¢ amount of processing done on the client and this is opposed to a Ëœfatâ„¢ client where most of the processing is carried out on the client machine.
Traditionally the thin client network architecture was typified by a powerful server connected to a series of Ëœdumb terminalsâ„¢ with limited functionality ,A thin client is a computer or a computer program which depends heavily on some other computer (its server) 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. The exact roles assumed by the server may vary, from providing data persistence (for example, for diskless nodes) to actual information processing on the client's behalf.
Thin clients occur as components of a broader computer infrastructure, where many clients share their computations with the same server. As such, thin client infrastructures can be viewed as the amortization of some computing service across several user-interfaces. This is desirable in contexts where individual fat clients have much more functionality or power than the infrastructure either requires or uses. This can be contrasted, for example, with grid computing.,
The next period of computing was typified by the use of simple I/O (input/output) terminals. These terminals were comprised of a keyboard for input and a text based CRT display for the computer output.
A completely different approached arose with advent of low cost microprocessors and the rise of the Personal Computer.
The Graphical User Interface (GUI)
The GUI was first commercialized on personal computers, the ideal platform since all of the processing power was dedicated to only one user at a time.
True Client/Server Computing- sharing compute power
Beyond the simple file sharing arrangement of early PC networks, other more powerful architectures arose. The next development was the effort to merge the best of both worlds into an environment of co-operative processing.
Working of thin client network
One or more computers to operate as a server. These computers tend to be of a much higher specification and more powerful than the other computers on the network.
An Operating System that supports Thin Client computing, e.g. Windows 2003 Server, Windows NT Terminal Server Edition (NT TSE), Linux, UNIX, Mac OS 9/ Mac OS X.
Centralised server software.
remote client management.
Where are thin client networks used
Organizations with multiple sites.
Schools, colleges, libraries, etcÂ¦
Installation and upgrading is easier.
Monitoring is easier.
Difficult to introduce viruses.
Prevent data loss.
Administrator control :
Only administrator can control.
Ease of upgrade/reduction of downtime :
Easily add another terminal to the network .
Hardware cost :
Energy saving :
Thin client terminals use considerably less energy than PCs because they perform very little processing on the client machine.
Facilitates Ëœhot-deskingâ„¢ or working across various sites.
Lack of disk drives
It is not possible to use floppy disks or CDs on the client machine with a true thin client solution.
Poor multimedia performance
Graphics intensive applications or multimedia programs are not suitable.
More bandwidth leads to slow processing.
Some models in thin clients
Types of thin client network
Ultra thin client
The user has a keyboard, mouse and a monitor.
No hard disk.
No memory cards.
Windows Based Terminals (WBT)
There are terminals which are designed to complement the Windows operating system and Windows products.
These are two types
Those with Windows Based Terminal Standard where the Windows environment is displayed on the desktop.
Two protocols namely RDP and ICA
Those which use a proprietary client operating environment with support for Citrix ICA to display Windows applications (eg Linux with Tarantella).
In built internet browser.
An emerging technology is the blade server which is sometimes referred to as a high-density server and is typically used for clustering.
protocols related to thin client networks
Citrix ICA protocol :
Independent Computing Architecture (ICA) is a proprietary protocol for an application server system, designed by Citrix Systems.
The protocol lays down a specification for passing data between server and clients, but is not bound to any one platform.
ICA client software is also built into various thin client platforms.
Remote Desktop Protocol(RDP)
It is a client-server protocol that allows a client device to connect to a Microsoft Terminal Server.
32-bit color support. 8-, 15-, 16-, and 24-bit color are also supported.
Remote Programs: Application publishing with client-side file type associations.
The Performance of Remote Display Mechanisms for
The growing popularity for thin client systems makes us to determine the factors that govern with performance of thin client architectures.
To choose the thin client computing model, we should measure the performance of the six popular thin client platforms.
Citric meta frame
Microsoft terminal services
Caching and compression.
Caching and Compression
If we apply the run-length encoding (RLE) data compression algorithm to the above hypothetical scan line, we get the following:
ICA and RDP both employ run-length encoding compression and cache fonts and bitmaps in memory and on disk at the client.
AIP also employs local client caching of display objects
VNC has RLE compression built-in with its display encoding format and employs a very simple form of on-screen caching
Characteristics of thin client platforms
Conclusion and future work
These results show that thin-client systems can provide good performance for web and multimedia applications in LAN environments.
With these experiments, we have analyzed various design choices underlying current thin-client systems.
Conclusions regarding thin-client system design.
First, higher-level graphics display primitives are not always more bandwidth efficient than lower-level display encoding primitives.
Second, display caching and compression are techniques which should be used with care as they can help or hurt thin-client performance.