LTSP is a collection of software that turns a normal GNU/Linux installation into a terminal server. This allows low-powered, low-cost thin-clients (or legacy hardware already in possession) to be used as terminals to the thin-client server. It requires only a PXE capable network interface, which many thin-clients and PCs have built-in already. This means that you need absolutely no physical storage media (hard disk, compact-flash, etc.) for your thin-client to boot to LTSP.
The process of booting a thin-client to an LTSP server is as follows:
• Thin-clients boot via a protocol called PXE (Pre-eXecution Environment)
• PXE requests an IP address from a local DHCP server
• The DHCP server passes additional parameters to the thin-client and downloads a Linux file system image via TFTP into a RAM disk on the client itself.
• The thin-client then boots the downloaded GNU/Linux image, detects hardware, and connects to the LTSP server’s X session (normally handled by LDM).
• From here, all operations such as authenticating your username and password, launching applications, and viewing websites are actually handled on the LTSP server rather than the thin-client. The LTSP server transfers all graphical information to the thin-client over the network. This allows very low powered thin-clients to utilize the power of the server for all operations. It also allows for large client deployments with reduced overall resource utilization, as 50thin-clients all running the popular OpenOffice suite under different sessions generally only require enough RAM for a single instance of OpenOffice (excluding per-user configuration which is minimal).