Thin Client
From Schoolforge-UK
Thin Client or Terminal Services is a technique used in a network setting were services are moved from the desktop to a server. Since the rise of the personal computer in office and educational settings, it is common to have each desktop workstation being a powerful computer with copious disk space, processing power and memory to run applications. Such workstations are networked together and commonly share file and print servers. Before this became the common topology, the norm was simple character terminals (occasionally graphics) connected to central servers that performed processing and provided storage. Thin Client is effectively a return to that topology but allowing for modern Graphics User Interfaces.
Advantages of Thin Client include:
- Large savings in capital cost and administration are possible
- Desktops can be less powerful, older computers, clients are often available for many different platforms including mobile devices and machines with no local discs (remote boot).
- Much easier administration as centralised on server, including simplified backup, updates and ability to restrict access
- No complicated update 'push' process
- Less power means lower running costs and 'greener'
- Lower repair costs
However:
- More powerful servers are needed
- More network traffic generated (100Base-T minimum)
- Cannot operate standalone or if connection broken
The common Thin Client standards and implementations are:
- LTSP Linux Terminal Services – based on the X Windows system (X11)
- Remote Desktop (RDP) Microsoft Windows system based on Citrix Metaframe technology
- VNC
- No Machine's NX Technology, works over low bandwidth
- ndiyo ultra thin client
- Web – yes HTML web applications are a form of Thin Client.
Due to some forward thinking in the early days of Unix development, Terminal Services is effectively built in. The X Windows system is used for Linux programs that have a GUI and this expects that the display/keyboard/mouse can be on another machine (the display server). LTSP provides a little packaging of X Windows to get things going. Contrast that with Windows where programs can assume direct access to all local hardware; still the Remote Desktop technology provides a very usable solution.
Linux Distributions with LTSP out of the box
Accessibility can be an issue with Thin Client though sound is now better support by LTSP solutions. Many Accessibility Aids and Assistive technology tools assume MS Windows and the lack of standard APIs means patchy support. See Assistive_Technology_with_Terminal_Servers project and the [www.oatsoft.org. OATSoft site].
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