This server is maintained by Dan Drake. If you'd like an account on the notebook server (see the "about" page for the differences between those two servers), you'll need to email me: dra...@kaist.edu. You can also email me if there are any problems with the servers or have questions.
Looking for a Korean version of the Sage notebook? 한글판을 찾고있는 거죠? http://math1.skku.ac.kr 방문해요.
This server runs Ubuntu Linux, which I recommend. Try it today!