J. River Media Center includes several servers.
Library Server, formerly called Media Server, can serve a media collection on one PC, so it can be played with another copy of MC on another PC anywhere on the Internet.
Tivo Server can serve MC's library to a TiVo.
UPnP Server can serve MC's library to a UPnP device, sometimes called a Media Receiver.
Remote Server is a small web server built into MC, and allows MC to be controlled from a web browser running on another PC.
The first three servers are located in MC's tree, under Services and Plug-ins, and that is where they are configured.
Remote Server is configured in MC's Options under Startup.
Media Server is now a small program that runs in the background and can start up any of the first three servers when needed. It will appear in the lower right corner of the desktop and it will show up in the task manager as Media Center.