The World's Oldest Computer Operating Systems: Shift Ranking of July 28
July 28, 2014
1. LEO I (1951) / 2. DYSEAC (1954) / 2. MIT's Tape Director (1954) / 4. General Motors Operating System for IBM 701 (1955) / 5. GM-NAA I/O (1956) / Source: Computer History Museum. CA
