Linux Terminal Server Project
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Linux Terminal Server Project (LTSP) is a free and open source add-on package for Linux that allows many people to simultaneously use the same computer. Applications run on the server with a terminal known as a thin client (also known as an X terminal) handling input and output. Generally, they are low-powered, lack a hard disk and are quieter than desktop computers because they do not have any moving parts.
This technology is becoming popular in schools as it allows the school to provide pupils access to computers without purchasing or upgrading expensive desktop machines. If the school does not have enough computers, new thin client machines are less costly than standard computers. If the school does have enough computers but they are a few years old, they may be able to extend the useful life of obsolescent computers by converting them into thin clients, since even a relatively slow CPU can deliver excellent performance as a thin client. Some examples of distributions using LTSP are AbulÉdu, the Cutter project, Deworks, Edubuntu, K12LTSP and Skolelinux.
In addition to the possibility of getting more performance for less money by getting one high-end server and turning their existing computers into thin clients, an educational institution may also gain more control over how their students are using computing resources by switching to a thin client configuration.
The founder and project leader of LTSP is Jim McQuillan, and LTSP is distributed under the terms of the GNU General Public License[1].
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[edit] The LTSP client boot process
On the LTSP server a chroot environment is set up with a minimal Linux operating system and X environment.
When a client[2] boots[3] from a local boot device (like a harddisk, CD-ROM or USB disk), it loads a small Linux kernel from that device which initializes the system and all of the peripherals that it recognizes. When configured for network booting (with mechanisms like Etherboot, Preboot Execution Environment (PXE) or NetBoot) the client first requests its own IP address and the IP address for the LTSP server via DHCP and loads the Linux kernel from a preconfigured Linux image on the LTSP server via the Trivial File Transfer Protocol (TFTP) service running on the LTSP server.
During this process the client makes a (new) DHCP request for the IP address of the LTSP server and the path to its chroot environment. When this information is retrieved, the client mounts the path on its root filesystem via the Network File System (NFS) service running on the LTSP server.
The client loads Linux from the NFS mounted root filesystem and finally starts the X windowing system. The client connects to the XDMCP login manager on the LTSP server. In case of the newer MueKow (LTSP 5) setup, the client first builds an SSH tunnel to the LTSP server's X environment, through which it will start the LDM login manager (on the LTSP server). From this point forward, all programs are started on the LTSP server, but displayed and operated from the client.
| Purpose | LTSP 4 | LTSP 5 (MueKow) |
|---|---|---|
| GUI Export | XDMCP | ssh -X |
| Remote login (X display manager) | KDM/GDM | LTSP Display Manager (LDM) |
| Distribution method | LTSP tarball | Native distribution |
| Authenticating server | XDMCP server | SSH server |
[edit] Massive deployment with MILLE-Xterm
The MILLE Project is funded by Canadian public agencies and school districts in the province of Quebec. MILLE means Modèle d'Infrastructure Logiciel Libre en Éducation (Free Software Infrastructure Model for Education) and is targeted at educational institutions. It is composed of four subprojects: a portal (based on uportal), an open-source middleware stack, a CD with free software for Windows/Mac and, finally, MILLE-XTERM. The base kernel of MILLE-XTERM is LTSP. The MILLE-XTERM provides a scalable infrastructure for massive X-Terminal deployment.
[edit] See also
- Terminal server
- Diskless Remote Boot in Linux: similar booting system that can use local hardware resources
- RULE Project
- VT100
- NX technology
- Time-sharing
- Multiseat
[edit] External links
- Official site
- K12 LTSP
- Edubuntu (search for 'LTSP' or 'thin client')
- LTSP Brazilian site
- The Cutter project
- Mille-Xterm: A solution based on LTSP including some more features like a loadbalancer, a configurator (in French)
- MILLE-Xterm Wiki
- An example of LTSP in action, providing an educational resource
- A Portuguese project dealing with LTSP usage in the classroom
- Medusa - (Edubuntu-based) LTSP at San Francisco State University
- Brazilian project using LTSP (in portuguese)
- Ubuntu Thin Client Howto (detailed)
- A collection of Ubuntu LTSP documentation
- Édutice: A LTSP / FreeNX / Mandriva based thin client / server solution (in French)
[edit] References
- ^ "LTSP homepage". "It's distributed under the GNU General Public License, meaning it's free and always will be."
- ^ Any networked computer capable of running Linux
- ^ James A. McQuillan. Chapter 1.1 from the LTSP 4.1 manual: The steps that the workstation will go through.
- ^ Jonathan Carter (and others). Ubuntu LTSP Tour: Technical differences (between LTSP 4 and 5)
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