One of Linux's features that differentiates it from Windows is that Linux has long supported remote logins. By using a remote login protocol, you can log into a Linux computer and run almost any program you could run if you were sitting at the Linux machine's console. The computer you use to access Linux could itself be running Linux, or it could be running Windows, Mac OS, or just about any other OS. This feature can be a tremendous boon in many environments, because it enables you to devote a small number of Linux systems to running important but seldom-used or resource non-intensive software that's not available for Windows. Users can then log into Linux from their Windows systems. As a system administrator, you can use this same feature to remotely administer a Linux system from a nearby office or from the other side of the world. Although Linux leads Windows in the area of remote logins, remote access servers are also available for Windows, so you can use these tools to access a Windows system from another computer, too.
Chapter 10 and Chapter 11 describe two broad classes of remote login protocols: those that work only in text mode and those that handle GUI accesses. The emphasis in these chapters is on accessing Linux systems, but both also describe some Windows remote-access tools. The third chapter of this part, Chapter 12, describes a way to stretch your hardware dollars or extend the life of old computers, by turning them into dedicated remote login clients, or thin clients as they've come to be known. Linux can function as a thin client OS or as a remote server accessed by thin clients.