The Hobbit monitoring software is used to monitor computer systems and ensure their proper function. Its modular structure allows Hobbit to be flexibly adapted to specific requirements. The software also has a web-based interface, which can be used to inspect the function of the objects to be monitored.
Hobbit is free software and runs on a whole range of unixoid operating system. For trademark reasons, in 2008 the project name was changed to Xymon.
You can find more information on the project page.