What is Terminal Server/Terminal Services on a Windows platform?

Question

I'm currently reading the MSDN description of some Windows APIs, such as WTSEnumerateSessions for instance, and it has words, such as

... is used ... on a Terminal Server

and

... requires running Terminal Services

But there seems to be no explanation of what all that "terminal" stuff is and how can I make sure that it is actually running.

Can I be sure that every Windows XP SP3, Vista and Windows 7 machine has those terminal services running?

Answer 1

Terminal Services is the component of Windows that allows remote desktop sessions. Generally, you have a Windows Server that is running the Terminal Services role. Clients, whether it be a windows 7 box, or a thin client, connect to the terminal server using the RDP protocol.

WTSEnumerateSessions is meant to be run on such a server and returns a enumerated list of client sessions.

Windows XP, Vista, and 7 all have the ability to host remote desktop sessions, however it is not as powerful as the actual Terminal Services (now called Remote Desktop Services in Windows Server 2008 R2) role.