A SEMINAR REPORT SUBMITTED ON THIN CLIENT COMPUTING
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Introduction
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 thin amount of processing done on the client and this is opposed to a fat 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 dumb terminals with limited functionality
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History
Early Computers
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.
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Personal Computer
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.
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Client/Server Architecture
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.
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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.
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Where are thin client networks used? Organizations with multiple sites. Remote working. Public places. Schools, colleges, libraries, etc
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Advantages
Manageability :
Installation and upgrading is easier. Monitoring is easier.
Security :
Difficult to introduce viruses. Prevent data loss.
Administrator control :
Only administrator can control.
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Ease of upgrade/reduction of downtime :
Easily add another terminal to the network . Faulty units.
Hardware cost :
less expensive
Energy saving :
Thin client terminals use considerably less energy than PCs because they perform very little processing on the client machine. Facilitates hot-desking or working across various sites.
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Disadvantages
Lack of disk drives
It is not possible to use floppy disks or CDs on the client machine with a true thin client solution.
Graphics intensive applications or multimedia programs are not suitable.
Poor multimedia performance
Bandwidth issues:
More bandwidth leads to slow processing.
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Some models in thin clients
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Types of thin client network
Ultra thin client
The user has a keyboard, mouse and a monitor. No hard disk. No memory cards.
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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).
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Internet terminals
In built internet browser.
Blade PC architecture
An emerging technology is the blade server which is sometimes referred to as a high-density server and is typically used for clustering.
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protocols related to thin client networks
Citrix ICA protocol :
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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.
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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.
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Architecture
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The Performance of Remote Display Mechanisms for Thin-Client Computing
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. Namely
Citric meta frame Microsoft terminal services Sun Ray Tarantella VNC X
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Performance measures
Web performance. Video performance. Caching and compression.
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Caching and Compression
Disk caching Memory catching
RLE
WWWWBWWWBBBWWWWWWWWWWWWWWWWWWWW WWWWBWWWWWWWWWWWWWW
If we apply the run-length encoding (RLE) data compression algorithm to the above hypothetical scan line, we get the following:
4W1B4W3B24W1B14W
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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
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Characteristics of thin client platforms
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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.
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Thank You
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