public access unix system:

The Super Dimension Fortress

The Super Dimension Fortress is a networked community of free software
authors, teachers, students, researchers, hobbyists, enthusiasts and
the blind.... Our mission is to provide remotely accessible computing facilities for
the advancement of public education, cultural enrichment, scientific
research and recreation.... The SDF community is made up of caring, highly skilled people who
operate behind the scenes to maintain a non-commercial INTERNET.