The PLATO system went through many revisions over a period of decades. The first system was programmed on the ILLIAC I system. The ILLIAC I measured ten feet high, two feet wide, and eight and a half feet tall and weighed about five tons. It utilized 2,800 vacuum tubes. In the 1970's a touch screen interface was utilized on a much smaller form factor, featuring a monochromatic orange display. Content was created with the TUTOR programming language, which was used to create thousands of hours of lesson material.
The early PLATO systems were used to teach K-12 as well as college courses near Urbana-Champaign, and eventually systems were sold to educational systems all over the world.