He uploaded the Oregon Trail game into the organization's time-sharing network by retyping it, copied from a printout of the 1971 BASIC code. In 1974, the Minnesota Educational Computing Consortium (MECC), a state-funded organization that developed educational software for the classroom, hired Rawitsch.
When the next semester ended, Rawitsch printed out a copy of the source code and deleted it from the minicomputer. Although the minicomputer's teletype and paper tape terminals that predate display screens were awkward to children, the game was immediately popular, and he made it available to users of the minicomputer time-sharing network owned by Minneapolis Public Schools. The game that would be later named The Oregon Trail debuted to Rawitsch's class on December 3, 1971. These are the original core gameplay concepts which have endured in every subsequent version: initial supply purchase occasional food hunting occasional supply purchase at forts inventory management of supplies variable travel speed depending upon conditions frequent misfortunes and game over upon death or successfully reaching Oregon. Rawitsch recruited two friends and fellow student teachers, Paul Dillenberger and Bill Heinemann, to help. He used HP Time-Shared BASIC running on a HP 2100 minicomputer to write a computer program to help teach the subject. In 1971, Don Rawitsch, a senior at Carleton College in Northfield, Minnesota, taught an 8th grade history class as a student teacher.