Super Dimension Fortress (SDF, also known as freeshell.org) is a non-profit public access UNIX shell provider on the Internet. It has been in continual operation since 1987 as a non-profit social club. The name is derived from the Japanese anime series Super Dimension Fortress Macross; the original SDF server was a Bulletin board system created by Ted Uhlemann for fellow Japanese anime fans. From its BBS roots, which have been well documented as part of the BBS: The Documentary project, SDF has grown into a feature-rich provider serving members around the world. More information...
According to PR-model, sdf.org is ranked 285,170th in multilingual Wikipedia, in particular this website is ranked 169,360th in English Wikipedia.
The website is placed before isetetu.co.jp and after dialprod.com in the BestRef global ranking of the most important sources of Wikipedia.